Engine Mechanical (h4so) Subaru Impreza WRX GD/GG рестайлинг 2

SPECIFICATION

ENGINE SPECIFICATION CHART

ENGINE SPECIFICATION CHART - US: UNDERSIZE OS: OVERSIZE

Exploded View Of Timing Belt With Torque Specifications. Scheme 41

Exploded View Of Cylinder Head And Camshaft With Torque Specifications. Scheme 42

Identifying Valve Rocker Assembly Components With Torque Specifications. Scheme 43

Identifying Cylinder Head And Valve Assembly Components. Scheme 44

Identifying Cylinder Block Components With Torque Specifications. Scheme 45

Identifying Crankshaft And Piston Components With Torque Specifications. Scheme 46

Identifying Engine Mounting Bracket And Front Cushion Rubber With Torque Specifications. Scheme 47

CAUTION

1. Wear work clothing, including a cap, protective goggles and protective shoes during operation.
2. Remove contamination including dirt and corrosion before removal, installation or disassembly.
3. Keep the disassembled parts in order and protect them from dust and dirt.
4. Before removal, installation or disassembly, be sure to clarify the failure. Avoid unnecessary removal, installation, disassembly and replacement.
5. Be careful not to burn yourself, because each part on the vehicle is hot after running.
6. Be sure to tighten fasteners including bolts and nuts to the specified torque.
7. Place shop jacks or rigid racks at the specified points.
8. Before disconnecting electrical connectors of sensors or units, be sure to disconnect the ground cable from battery.
9. All parts should be thoroughly cleaned, paying special attention to the engine oil passages, pistons and bearings.
10. Rotating parts and sliding parts such as piston, bearing and gear should be coated with oil prior to assembly.
11. Be careful not to let oil, grease or coolant contact the timing belt, clutch disc and flywheel.
12. All removed parts, if to be reused, should be reinstalled in the original positions and directions.
13. Bolts, nuts and washers should be replaced with new ones as required.
14. Even if necessary inspections have been made in advance, proceed with assembly work while making rechecks.
15. Remove or install the engine in an area where chain hoists, lifting devices, etc. are available for ready use.
16. Be sure not to damage coated surfaces of body panels with tools, or not to stain seats and windows with coolant or oil. Place a cover over fenders, as required, for protection.
17. Prior to starting work, prepare the following: Service tools, clean cloth, containers to catch coolant and oil, wire ropes, chain hoist, transmission jacks, etc.
18. Lift-up or lower the vehicle when necessary. Make sure to support the correct positions.

SPECIAL TOOL

SPECIAL TOOL ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS 18231AA010 CAM SPROCKET WRENCH Used for removing and installing cam sprocket. (LH side) CAM SPROCKET WRENCH (499207100) can also be used. 18482AA010 (Newly adopted tool) CARTRIDGE Troubleshooting for electrical system. 22771AA030 SUBARU SELECT MONITOR KIT Troubleshooting for electrical system. 498267800 CYLINDER HEAD TABLE Used for replacing valve guides. Used for removing and installing valve spring. 498277200 STOPPER SET Used for installing automatic transmission assembly to engine. 498457000 ENGINE STAND ADAPTER RH Used with ENGINE STAND (499817100). 498457100 ENGINE STAND ADAPTER LH Used with ENGINE STAND (499817100). 498497100 CRANKSHAFT STOPPER Used for stopping rotation of flywheel when loosening/tightening crank pulley bolt. 498747300 PISTON GUIDE Used for installing piston in cylinder. 498857100 VALVE OIL SEAL GUIDE Used for press-fitting of intake and exhaust valve guide oil seals. 499017100 PISTON PIN GUIDE Used for installing piston pin, piston and connecting rod. 499037100 CONNECTING ROD BUSHING REMOVER & INSTALLER Used for removing and installing connecting rod bushing. 499587200 CRANKSHAFT OIL SEAL INSTALLER Used for installing crankshaft oil seal. Used with CRANKSHAFT OIL SEAL GUIDE (499597100). 499587500 OIL SEAL INSTALLER Used for installing camshaft oil seal. Used with OIL SEAL GUIDE (499597000). 499587700 CAMSHAFT OIL SEAL INSTALLER Used for installing cylinder head plug. 499097700 PISTON PIN REMOVER ASSY Used for removing piston pin. 499207400 CAM SPROCKET WRENCH Used for removing and installing cam sprocket. (RH side) 499497000 TORX PLUS® Used for removing and installing camshaft cap. 499587100 OIL SEAL INSTALLER Used for installing oil pump oil seal. 499597000 OIL SEAL GUIDE Used for installing camshaft oil seal. Used with CAMSHAFT OIL SEAL INSTALLER (499587500). 499597100 CRANKSHAFT OIL SEAL GUIDE Used for installing crankshaft oil seal. Used with CRANKSHAFT OIL SEAL INSTALLER (499587200). 499718000 VALVE SPRING REMOVER Used for removing and installing valve spring. 499767200 VALVE GUIDE REMOVER Used for removing valve guides. 499767400 VALVE GUIDE REAMER Used for reaming valve guides. 499767700 VALVE GUIDE ADJUSTER Used for installing valve guides. (Intake side) 499767800 VALVE GUIDE ADJUSTER Used for installing valve guides. (Exhaust side) 499817100 ENGINE STAND Stand used for engine disassembly and assembly. Used with ENGINE STAND ADAPTER RH (498457000) & LH (498457100). 499977100 CRANK PULLEY WRENCH Used for stopping rotation of crank pulley when loosening/tightening crank pulley bolt. 18332AA000 OIL FILTER WRENCH Used for removing and installing oil filter. (Outer diameter: 68 mm (2.68 in)) 18332AA010 OIL FILTER WRENCH Used for removing and installing oil filter. (Outer diameter: 65 mm (2.56 in)) 499987500 CRANKSHAFT SOCKET Used for rotating crankshaft. 42099AE000 CONNECTOR REMOVER Used for removing quick connector. 18354AA000 VALVE ROCKER HOLDER Used for installing valve rocker assembly (Intake). (2 in one set) 18258AA000 SPRING INSTALLER Used for installing valve rocker assembly (Intake)

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GENERAL TOOL

GENERAL TOOL

PROCEDURE

It is possible to conduct the following service procedures with engine on the vehicle, however, the procedures described in this section are based on the condition that the engine is removed from the vehicle.

1. V-belt
2. Timing belt
3. Valve rocker assembly
4. Camshaft
5. Cylinder head

INSPECTION

Scheme 72

1. After warming-up the engine, turn the ignition switch to OFF.
2. Make sure that the battery is fully charged.
3. Release the fuel pressure. < Ref. to «RELEASING OF FUEL PRESSURE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so__releasing-of-fuel-pressure), PROCEDURE, Fuel. >
4. Remove all the spark plugs. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/ignition-system/#ignition-h4so-engine__removal), Spark Plug. >
5. Fully open the throttle valve.
6. Check the starter motor for satisfactory performance and operation.
7. Fix the compression gauge securely against the spark plug hole. NOTE: The screw of screw-in type compression gauge (put into cylinder head spark plug hole) should be less than 18 mm (0.71 in) long.
8. Crank the engine by means of the starter motor, and then read the maximum value on the gauge when the needle of gauge is steady. (Scheme 48): Checking Compression Of Engine Using Compression Gauge
9. Perform at least two measurements per cylinder, and make sure that the values are correct. Compression (350 rpm and fully open throttle): Standard: 1,020 - 1,275 kPa (10.4 - 13.0 kgf/cm 2, 148 - 185 psi) Difference between cylinders: 49 kPa (0.5 kgf/cm 2, 7 psi) or less

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1. Before checking the idle speed, check the following: Ensure the air cleaner element is free from clogging, ignition timing is correct, spark plugs are in good condition, and hoses are connected properly. Ensure the malfunction indicator light does not illuminate.
2. Idle the engine.
3. Stop the engine, and turn the ignition switch to OFF.
4. When using Subaru Select Monitor, refer to the following. < Ref. to «SPECIAL TOOL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__special-tool), PREPARATION TOOL, General Description. > Insert the cartridge to the Subaru Select Monitor. Connect the Subaru Select Monitor to data link connector. (Scheme 49): Locating Data Link Connector Turn the ignition switch to ON, and Subaru Select Monitor power switch to ON. Select {Each System Check} in the Main Menu. Select {Engine} in the Selection Menu. Select {Current Data Display & Save} in the Engine Control System Diagnosis. Select {Data Display} in the Data Display Menu. Start the engine, and read engine idle speed.
5. When using the tachometer (Secondary pick-up type): Attach the pick-up clip to No. 1 cylinder spark plug cord. Start the engine, and read engine idle speed. (Scheme 50): Checking Engine Idle Speed Using Tachometer NOTE: This ignition system provides simultaneous ignition for #1 and #2 plugs. It must be noted that some tachometers may register twice that of actual engine speed.
6. Check the idle speed when unloaded. (With headlights, heater fan, rear defroster, radiator fan, A/C, etc. OFF) Idle speed [No load and gears in "N" or "P" range]: MT model 650±100 rpm AT model 700±100 rpm
7. Check the idle speed when loaded. (Turn the A/C switch to "ON" and operate the compressor for at least one minute before measurement. Idle speed [A/C "ON" and gears in "N" or "P" range]: 850±100 rpm NOTE: Idle speed cannot be adjusted manually, because the idle speed is automatically adjusted. If the idle speed is out of specifications, refer to General Diagnosis Table under "Engine Control System". < Ref. to «BASIC DIAGNOSTIC PROCEDURE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/testing-diagnostics/#engine-controls-engine-diagnostics-h4so). >

1. Before checking the ignition timing, check the following: Ensure the air cleaner element is free from clogging, spark plugs are in good condition, and that hoses are connected properly. Ensure the malfunction indicator light does not illuminate.
2. Idle the engine.
3. Stop the engine, and turn the ignition switch to OFF.
4. When using Subaru Select Monitor, refer to the following. < Ref. to «SPECIAL TOOL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__special-tool), PREPARATION TOOL, General Description. > Insert the cartridge to the Subaru Select Monitor. Connect the Subaru Select Monitor to data link connector. (Scheme 51): Locating Data Link Connector Turn the ignition switch to ON, and Subaru Select Monitor power switch to ON. Select {Each System Check} in the Main Menu. Select {Engine} in the Selection Menu. Select {Current Data Display & Save} in the Engine Control System Diagnosis. Select {Data Display} in the Data Display Menu. Start the engine, and read the ignition timing by idle speed. Ignition timing [BTDC/rpm]: MT model 10°±8°/650 AT model 15°±8°/700 If the timing is not correct, check the ignition control system. < Ref. to «BASIC DIAGNOSTIC PROCEDURE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/testing-diagnostics/#engine-controls-engine-diagnostics-h4so). >

1. Idle the engine.
2. Disconnect the brake vacuum hose from the intake manifold, and then install the vacuum gauge.
3. Keep the engine at the idle speed, and read the vacuum gauge indication.

By observing the gauge needle movement, the internal condition of the engine can be diagnosed as described below.

Scheme 75

Vacuum pressure (at idling, A/C "OFF")

Less than -60.0 kPa (-450 mmHg, -17.72 inHg)

VACUUM GAUGE INDICATION CHART

Scheme 76

1. Disconnect the ground cable from battery.
2. Remove the generator from bracket. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/charging-system/#startingcharging-systems-h4so), Generator. >
3. Disconnect the connector from oil pressure switch.
4. Remove the pressure switch from cylinder block. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/lubrication-system/#lubrication-h4so-engine), Oil Pressure Switch. >
5. Connect the oil pressure gauge hose to cylinder block.
6. Connect the battery ground cable to battery.
7. Start the engine, and measure oil pressure. (Scheme 53): Checking Oil Pressure Using Pressure Gauge Oil pressure: Standard 98 kPa (1.0 kgf/cm 2, 14 psi) or more at 600 rpm 294 kPa (3.0 kgf/cm 2, 43 psi) or more at 5,000 rpm CAUTION: If the oil pressure is out of specification, check oil pump, oil filter and lubrication line. < Ref. to «INSPECTION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/lubrication-system/#lubrication-h4so-engine), Engine Lubrication System Trouble in General. > If the oil pressure warning light is turned to ON but oil pressure is within specification, replace the oil pressure switch. < Ref. to «INSPECTION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/lubrication-system/#lubrication-h4so-engine), Engine Lubrication System Trouble in General. > NOTE: The specified value is based on an engine oil temperature of 80°C (176°F).
8. After measuring the oil pressure, install the oil pressure switch. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/lubrication-system/#lubrication-h4so-engine), Oil Pressure Switch. > Tightening torque: 25 N.m (2.5 kgf-m, 18.4 ft-lb)

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1. Release the fuel pressure. < Ref. to «RELEASING OF FUEL PRESSURE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so__releasing-of-fuel-pressure), PROCEDURE, Fuel. >
2. Disconnect the fuel delivery hose from fuel damper, and connect a fuel pressure gauge. (Scheme 54): Checking Fuel Pressure Using Fuel Pressure Gauge
3. Connect the connector of fuel pump relay. (Scheme 55): Locating Fuel Pump Relay Connector
4. Start the engine.
5. After warming-up the engine, measure the fuel pressure. Fuel pressure: Standard: 339.5 - 360.5 kPa (3.5 - 3.7 kgf/cm 2, 49 - 52 psi) NOTE: The fuel pressure gauge registers 10 to 20 kPa (0.1 to 0.2 kgf/cm 2, 1 to 3 psi) higher than standard values during high-altitude operations.

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1. Set the vehicle on a lift.
2. Lift-up the vehicle.
3. Remove the under cover.
4. Lower the vehicle.
5. Disconnect the ground cable from battery.
6. Remove the timing belt cover (LH). (Scheme 56): Identifying Timing Belt Cover
7. Remove the fuel injector. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Fuel Injector. >
8. When inspecting #1 and #3 cylinders: Disconnect the spark plug cords from spark plugs RH side. < Ref. to «RH SIDE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/ignition-system/#ignition-h4so-engine__rh-side), REMOVAL, Spark Plug. > Disconnect the PCV hose from rocker cover (RH). Remove the bolts, then remove the rocker cover (RH).
9. When inspecting #2 and #4 cylinders: Disconnect the spark plug cords from spark plugs (LH Side). < Ref. to «LH SIDE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/ignition-system/#ignition-h4so-engine__lh-side), REMOVAL, Spark Plug. > Disconnect the PCV hose from rocker cover (LH). Remove the bolts, then remove the rocker cover (LH).
10. Set #1 cylinder piston to top dead center of compression stroke by rotating the crank pulley clockwise using the socket wrench. NOTE: When the arrow mark (A) on cam sprocket (LH) comes exactly to the top, #1 cylinder piston is brought to the top dead center of compression stroke. (Scheme 57): Identifying Arrow Mark On Cam Sprocket
11. Measure #1 cylinder valve clearance using thickness gauge. CAUTION: Insert the thickness gauge (A) in as horizontally as possible with respect to the valve stem end face. Measure the exhaust valve clearances while lifting-up the vehicle. Valve clearance (Standard): Intake: 0.20±0.04 mm (0.0079±0.0016 in) Exhaust: 0.25±0.04 mm (0.0098±0.0016 in) (Scheme 58): Measuring Exhaust Valve Clearances Using Thickness Gauge
12. If necessary, adjust the valve clearance. < Ref. to «ADJUSTMENT»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__adjustment), Valve Clearance. >
13. Measure the valve clearance in #3, #2 and #4 cylinder in the same measurement procedure as #1 cylinder. NOTE: Be sure to set the cylinder pistons to their respective top dead centers on compression stroke before measuring valve clearances. By rotating the crank pulley clockwise every 180° from the state that #1 cylinder piston is on the top dead center of compression stroke, #3, #2 and #4 cylinder pistons come to the top dead center of compression stroke in this order.
14. After inspection, install the related parts in the reverse order of removal.

ADJUSTMENT

Scheme 82

1. Set #1 cylinder piston to top dead center of compression stroke by rotating the crank pulley clockwise using the socket wrench. NOTE: When the arrow mark (A) on cam sprocket (LH) comes exactly to the top, #1 cylinder piston is brought to the top dead center of compression stroke. (Scheme 59): Identifying Arrow Mark On Cam Sprocket
2. Adjust the #1 cylinder valve clearance. Loosen the valve rocker nut and screw. Place a suitable thickness gauge. While noting the valve clearance, tighten the valve rocker adjusting screw. When the specified valve clearance is obtained, tighten the valve rocker nut. Tightening torque: 9.75 N.m (1.0 kgf-m, 7.2 ft-lb) CAUTION: Insert the thickness gauge in as horizontally as possible with respect to the valve stem end face. Adjust the exhaust valve clearances while lifting-up the vehicle. Valve clearance Intake: 0.20±0.04 mm (0.0079±0.0016 in) Exhaust: 0.25±0.04 mm (0.0098±0.0016 in) (Scheme 60): Adjusting Exhaust Valve Clearances
3. Adjust the valve clearance in #3, #2 and #4 cylinder in the same adjustment procedure as #1 cylinder. NOTE: Be sure to set the cylinder pistons to their respective top dead centers on compression stroke before adjusting valve clearances. By rotating the crank pulley clockwise every 180° from the state that #1 cylinder piston is on the top dead center of compression stroke, #3, #2 and #4 cylinder pistons come to the top dead center of compression stroke in this order.
4. Ensure the valve clearances of each cylinder are within specifications. If necessary, readjust the valve clearances.

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1. Set the vehicle on a lift.
2. Open the front hood fully and support with the front food stay.
3. Collect the refrigerant from A/C system. < Ref. to «PROCEDURE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/general-servicing-all-makes/#hvac-system-heater-ventilator-and-ac), Refrigerant Recovery Procedure. >
4. Release the fuel pressure. < Ref. to «RELEASING OF FUEL PRESSURE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so__releasing-of-fuel-pressure), PROCEDURE, Fuel. >
5. Disconnect the ground cable from battery.
6. Open the fuel filler flap lid and remove the fuel filler cap.
7. Remove the air intake duct, air cleaner case and air intake chamber. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#intake-induction-h4so-engine), Air Intake Duct. > < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#intake-induction-h4so-engine), Air Cleaner Case. > < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#intake-induction-h4so-engine), Air Intake Chamber. >
8. Remove the under cover.
9. Remove the radiator from vehicle. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/cooling-fan/#cooling-system-h4so), Radiator. >
10. Disconnect the A/C pressure hoses from A/C compressor.
11. Remove the air intake chamber stay. (Scheme 61): Identifying Air Intake Chamber Stay
12. Disconnect the following connectors and cables. Front oxygen (A/F) sensor connector Rear oxygen sensor connector (Scheme 62): Identifying Front Oxygen (A/F) Sensor Connector And Rear Oxygen Sensor Connector Engine ground cable (Scheme 63): Identifying Engine Ground Cable Engine harness connectors (Scheme 64): Identifying Engine Harness Connectors Generator connector and terminal (Scheme 65): Identifying Generator Connector And Terminal A/C compressor connectors (Scheme 66): Locating A/C Compressor Connectors Power steering switch connector (Scheme 67): Locating Power Steering Switch Connector
13. Disconnect the following hoses. Brake booster vacuum hose (Scheme 68): Locating Brake Booster Vacuum Hose Heater inlet and outlet hoses
14. Remove the power steering pump from bracket. Loosen the lock bolt and slider bolt, and then remove the front side V-belt. < Ref. to «FRONT SIDE BELT»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__front-side-belt), REMOVAL, V-belt. > Remove the pipe with bracket. (Scheme 69): Locating Heater Inlet And Outlet Hoses Bracket With Bolts Remove the bolts which install the power steering pump to bracket. (Scheme 70): Locating Power Steering Pump Bracket Bolts Remove the power steering tank from bracket by pulling it upward. (Scheme 71): Locating Power Steering Tank Bracket Move the power steering pump to the right side wheel apron to prevent it from falling. NOTE: Use a shop cloth not to scratch. (Scheme 72): Identifying Power Steering Pump
15. Remove the front and center exhaust pipe. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/exhaust/#exhaust-h4so-engine__removal), Front Exhaust Pipe. >
16. Remove the nuts which hold lower side of transmission to engine. (Scheme 73): Locating Lower Side Of Transmission To Engine Nuts Location
17. Remove the nuts which install front cushion rubber onto front crossmember. (Scheme 74): Locating Front Cushion Rubber Onto Front Crossmember Nuts
18. Remove the housing cover mounting bolts.
19. Separate the torque converter clutch from drive plate. (AT model) Lower the vehicle. Remove the service hole plug. Remove the bolts which hold torque converter clutch to drive plate. Remove all the bolts by rotating them in the direction of engine rotation little by little using a socket wrench. see scheme 35: Removing Housing Cover Mounting Bolts Using Socket Wrench
20. Remove the pitching stopper. (Scheme 75): Identifying Pitching Stopper
21. Disconnect the fuel delivery hose (A) and evaporation hose (B). < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Fuel Delivery & Evaporation Lines. > CAUTION: Catch fuel from the hose into container. Disconnect the hose with its end wrapped with cloth to prevent fuel from splashing. ST 42099AE000 CONNECTOR REMOVER (Scheme 76): Disconnecting Fuel Delivery Hose (A) And Evaporation Hose Using Connector Remover
22. Support the engine with a lifting device and wire ropes. (Scheme 77): Supporting Engine With Lifting Device And Wire Ropes
23. Support the transmission with a garage jack. CAUTION: Doing this is very important because the transmission lowers for its own weight. This work is also of great importance for facilitating reinstallation. (Scheme 78): Supporting Transmission With Garage Jack CAUTION: Before removing the engine away from transmission, check to be sure no work has been overlooked.
24. Separation of engine and transmission. Remove the starter. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/charging-system/#startingcharging-systems-h4so__removal), Starter. > Remove the bolts which hold upper side of transmission to engine. (Scheme 79): Locating Upper Side Of Transmission Bolts Location
25. Set the ST to converter case. (AT model) ST 498277200 STOPPER SET (Scheme 80): Setting ST To Converter Using Stopper Set Case ST 498277200 (At Model)
26. Remove the engine from vehicle. Slightly raise the engine. Raise the transmission with garage jack. Move the engine horizontally until main shaft is withdrawn from clutch cover. Slowly move the engine away from engine compartment. NOTE: Be careful not to damage adjacent parts or body panels with crank pulley, oil level gauge, etc.
27. Remove the front cushion rubbers.

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1. Install the front cushion rubbers. Tightening torque: 35 N.m (3.6 kgf-m, 25.8 ft-lb)
2. Position the engine in engine compartment and align it with transmission. NOTE: Be careful not to damage adjacent parts or body panels with crank pulley, oil level gauge, etc. (Scheme 81): Supporting Engine With Lifting Device And Wire Ropes
3. Apply a small amount of grease to splines of main shaft. (MT model)
4. Tighten the bolts which hold upper side of transmission to engine. Tightening torque: 50 N.m (5.1 kgf-m, 36.9 ft-lb) see scheme 43: Locating Upper Side Of Transmission To Engine Bolts Location
5. Remove the lifting device and wire ropes.
6. Remove the garage jack.
7. Install the pitching stopper. Tightening torque: T1: 50 N.m (5.1 kgf-m, 36.9 ft-lb) T2: 58 N.m (5.9 kgf-m, 42.8 ft-lb) (Scheme 82): Identifying Pitching Stopper
8. Remove the ST from converter case. (AT model) NOTE: Be careful not to drop the ST into the converter case when removing the ST. ST 498277200 STOPPER SET
9. Install the starter. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/charging-system/#startingcharging-systems-h4so__installation), Starter. >
10. Install the torque converter clutch to drive plate. (AT model) Tighten the bolts which hold torque converter clutch to drive plate. Tighten all the bolts by rotating them in the direction of engine rotation little by little using a socket wrench. CAUTION: Be careful not to drop bolts into the torque converter clutch housing. Tightening torque: 25 N.m (2.5 kgf-m, 18.4 ft-lb) (Scheme 83): Removing Housing Cover Mounting Bolts Using Socket Wrench Clog the service hole plug and prevent foreign matters from being mixed.
11. Install the power steering pump on bracket. Install the power steering tank to bracket. (Scheme 84): Locating Power Steering Tank Bracket Install the power steering pump on bracket, and tighten the bolts. Tightening torque: 22 N.m (2.2 kgf-m, 16 ft-lb) (Scheme 85): Locating Power Steering Pump Bracket Bolts Install the pipe with their bracket. (Scheme 86): Locating Heater Inlet And Outlet Hoses Bracket With Bolts Connect the power steering switch connector. (Scheme 87): Locating Power Steering Switch Connector Install the front side belt and adjust it. < Ref. to «FRONT SIDE BELT»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__front-side-belt), INSTALLATION, V-belt. >
12. Lift-up the vehicle.
13. Tighten the nuts which hold lower side of transmission to engine. Tightening torque: 50 N.m (5.1 kgf-m, 36.9 ft-lb) (Scheme 88): Locating Lower Side Of Transmission To Engine Nuts Location
14. Tighten the nuts which install the front cushion rubber onto crossmember. Tightening torque: 85 N.m (8.7 kgf-m, 63 ft-lb) NOTE: Make sure the front cushion rubber mounting bolts (A) and locator (B) are securely installed. (Scheme 89): Locating Front Cushion Rubber Mounting Bolts And Locator
15. Install the front and center exhaust pipe. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/exhaust/#exhaust-h4so-engine__installation), Front Exhaust Pipe. >
16. Lower the vehicle.
17. Connect the following hoses: Fuel delivery hose and evaporation hose Heater inlet and outlet hoses Brake booster vacuum hose
18. Connect the following connectors: Front oxygen (A/F) sensor connector Rear oxygen sensor connector Engine ground cable Tightening torque: 14 N.m (1.4 kgf-m, 10.1 ft-lb) Engine harness connectors Generator connector and terminal A/C compressor connector
19. Install the air intake chamber stay. Tightening torque: 16 N.m (1.6 kgf-m, 11.6 ft-lb)
20. Tighten the engine ground cable. Tightening torque: 14 N.m (1.4 kgf-m, 10.1 ft-lb)
21. Install the A/C pressure hoses. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/general-servicing-all-makes/#hvac-system-heater-ventilator-and-ac), Hose and Tube. >
22. Install the radiator to vehicle. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/cooling-fan/#cooling-system-h4so), Radiator. >
23. Install the air intake duct, air cleaner case and air intake chamber. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#intake-induction-h4so-engine), Air Intake Duct. > < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#intake-induction-h4so-engine), Air Cleaner Case. > < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#intake-induction-h4so-engine), Air Intake Chamber. >
24. Install the under cover.
25. Install the battery in the vehicle, and connect cables.
26. Fill engine coolant. < Ref. to «FILLING OF ENGINE COOLANT»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/cooling-fan/#cooling-system-h4so), REPLACEMENT, Engine Coolant. >
27. Check the ATF level and replenish it if necessary. < Ref. to «INSPECTION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/automatic-trans/#automatic-transmission__inspection), Automatic Transmission Fluid. >
28. Charge the A/C system with refrigerant. < Ref. to «PROCEDURE»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/general-servicing-all-makes/#hvac-system-heater-ventilator-and-ac), Refrigerant Charging Procedure. >
29. Remove the front hood stay, and close the front hood.
30. Take off the vehicle from a lift.

1. Check pipes, hoses, connectors and clamps are installed firmly.
2. Check that the engine coolant and ATF are at specified levels.
3. Start the engine, and make sure that no leaks of exhaust gas, engine coolant and fuel, noise and vibrations.

REMOVAL

1. Remove the engine assembly. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__removal) , Engine Assembly. >
2. Remove the engine mounting from engine assembly.

INSTALLATION

Install in the reverse order of removal.

Tightening torque

Engine mounting

35 N.m (3.6 kgf-m, 25.8 ft-lb)

Make sure that no crack or other damages do not exist.

Scheme 107

1. After removing the engine from the body, secure it in the ST shown below. ST1 498457000 ENGINE STAND ADAPTER RH ST2 498457100 ENGINE STAND ADAPTER LH ST3 499817100 ENGINE STAND (Scheme 90): Identifying Engine Stand Adapter RH (498457000) And Engine Stand Adapter LH (498457100)
2. In this section the procedures described under each index are all connected and stated in order. The procedure for overhauling of the engine will be completed when you go through all steps in the process. Therefore, in this section, to conduct the particular procedure within the flow of a section, you need to go back and conduct the procedure described previously in order to do that particular procedure.

Note. Perform the following procedures with the engine installed to the body.

Scheme 108

Scheme 109

1. Remove the V-belt covers. (Scheme 91): Identifying V-Belt Covers
2. Loosen the lock bolt (A).
3. Loosen the slider bolt (B).
4. Remove the front side belt (C). (Scheme 92): Locating Lock Bolt And Slider Bolt

Scheme 110

Scheme 111

1. Loosen the lock nut (A).
2. Loosen the slider bolt (B). (Scheme 93): Identifying Rear Side Belt Slider Bolt And Lock Nut
3. Remove the rear side belt.
4. Remove the belt tensioner. (Scheme 94): Identifying Belt Tensioner

Note. Wipe off any oil or water on the belt and pulley.

FRONT SIDE BELT

1. Install a V belt (C), and tighten the slider bolt so as to obtain the specified belt tension. < Ref. to «INSPECTION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Tighten the lock bolt (A).
3. Tighten the slider bolt (B). Tightening torque: Lock bolt (A): 25 N.m (2.5 kgf-m, 18.4 ft-lb) Slider bolt (B): 8 N.m (0.8 kgf-m, 5.9 ft-lb) (Scheme 95): Locating Front Side Belt Slider Bolt And Lock Bolt

REAR SIDE BELT

1. Install the belt tensioner.
2. Install a V belt, and tighten the slider bolt (B) so as to obtain the specified belt tension. < Ref. to «INSPECTION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
3. Tighten the lock nut (A). Tightening torque: Lock nut (A): 23 N.m (2.3 kgf-m, 17.0 ft-lb) (Scheme 96): Identifying Rear Side Belt Slider Bolt And Lock Nut

Scheme 112

Scheme 113

1. Replace the belts, if cracks, fraying or wear is found.
2. Remove the V-belt cover and reservoir tank. (with belt tension gauge)
3. Check the V-belt tension and adjust it if necessary by changing the generator installing position or idler pulley installing position. Belt tension (with belt tension gauge) When installing new parts: 618 - 755 N (63 - 77 kgf, 139 - 170 lbf) At inspection: 490 - 640 N (50 - 65 kgf, 110 - 144 lbf) When installing new parts: 740 - 880 N (75 - 90 kgf, 166 - 198 lbf) At inspection: 350 - 450 N (36 - 46 kgf, 79 - 101 lbf) (Scheme 97): View Of Pulley And Drive Belt Belt tension (without belt tension gauge) (A) When installing new parts: 7 - 9 mm (0.276 - 0.354 in) At inspection: 9 - 11 mm (0.354 - 0.433 in) (B) When installing new parts: 7.5 - 8.5 mm (0.295 - 0.335 in) At inspection: 9.0 - 10.0 mm (0.354 - 0.394 in) (Scheme 98): View Of Pulley And Drive Belt

Scheme 114

1. Remove the V-belts. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Remove the crank pulley bolt. To lock the crankshaft, use ST. ST 499977100 CRANK PULLEY WRENCH (Scheme 99): Removing Crank Pulley Bolt Using Crank Pulley Wrench (ST 499977100)
3. Remove the crank pulley.

1. Install the crank pulley.
2. Install the pulley bolt. To lock the crankshaft, use ST. ST 499977100 CRANK PULLEY WRENCH Clean the crankshaft thread using compressed air. Apply engine oil to the crank pulley bolt seat and thread. Tighten the bolts temporarily with tightening torque of 44 N.m (4.5 kgf-m, 33 ft-lb). Tighten the crank pulley bolts. Tightening torque: 180 N.m (18.4 kgf-m, 132.8 ft-lb) (Scheme 100): Removing Crank Pulley Bolt Using Crank Pulley Wrench (ST 499977100)
3. Confirm that the tightening angle of crank pulley bolt is 65° or more. If the tightening angle of crank pulley bolt is less than 65°, conduct the following procedures. Replace the crank pulley bolts and clean them. Crank pulley bolt: Part No. 12369AA011 Clean the crankshaft thread using compressed air. Apply engine oil to the crank pulley bolt seat and thread. Tighten the bolts temporarily with tightening torque of 44 N.m (4.5 kgf-m, 33 ft-lb). Tighten the crank pulley bolts keeping them in an angle between 65° and 75°. NOTE: Conduct the tightening procedures by confirming the turning angle of crank pulley bolt referring to the gauge indicated on timing belt cover.
4. Install the belt tensioner. (Scheme 101): Identifying Belt Tensioner
5. Install the V-belts. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >

1. Make sure the V-belt is not worn or otherwise damaged.
2. Check the tension of the belt. < Ref. to «INSPECTION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so) , V-belt. >

Scheme 115

1. Remove the V-belts. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
3. Remove the timing belt cover (LH).
4. Remove the front timing belt cover. (Scheme 102): Identifying Front Timing Belt Cover And Timing Belt Cover (LH)

Scheme 116

1. Install the front timing belt cover. Tightening torque: 5 N.m (0.5 kgf-m, 3.6 ft-lb)
2. Install the timing belt cover (LH). Tightening torque: 5 N.m (0.5 kgf-m, 3.6 ft-lb) (Scheme 103): Identifying Timing Belt Cover (LH)
3. Install the crank pulley. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
4. Install the V-belts. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >

Check the cover for damage.

Scheme 117

Scheme 118

Scheme 119

Scheme 120

Scheme 121

Scheme 122

Scheme 123

1. Remove the V-belts. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
3. Remove the timing belt cover. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
4. Remove the timing belt guide. (MT model) see scheme 66: Locating Timing Belt Guide (MT Model)
5. If the alignment mark or arrow mark (which indicates rotation direction) on timing belt fade away, put new marks before removing the timing belt as shown in procedures below. To turn crankshaft, use the ST: Align the mark (a) of sprocket to the cylinder block notch (b), and then ensure the right side cam sprocket mark (c), cam cap and cylinder head matching surface (d) or left side cam sprocket mark (e), timing belt cover notch (f) are properly adjusted. ST 499987500 CRANKSHAFT SOCKET see scheme 67: Turning Crankshaft Using ST (499987500) Crankshaft Socket (Scheme 104): Identifying Align Mark (A) Of Sprocket To Cylinder Block Notch Using white paint, put alignment marks or arrow marks on the timing belts in relation to the crank sprocket and cam sprockets. see scheme 69: Putting Alignment Marks Or Arrow Marks On Timing Belts Specified data: Z 7: Length of 46.8 teeth Z 2: Length of 43.7 teeth see scheme 70: Identifying Drive Belt Length
6. Remove the belt idler (No. 2). see scheme 71: Removing Belt Idler (No. 2)
7. Remove the belt idler No. 2.
8. Remove the timing belt. see scheme 72: Identifying Belt Idler No. 2 And Timing Belt

Scheme 124

Scheme 125

1. Remove the belt idler (No. 1) see scheme 73: Identifying Belt Idler (No. 1)
2. Remove the automatic belt tension adjuster assembly. (Scheme 105): Removing Automatic Belt Tension Adjuster Assembly

Scheme 126

Scheme 127

Scheme 128

1. Preparation for installation of automatic belt tension adjuster assembly. CAUTION: Always use a vertical type pressing tool to move the adjuster rod down. Do not use a lateral type vise. Push the adjuster rod vertically. Press-in the push adjuster rod gradually taking more than three minutes. Do not allow press pressure to exceed 9,807 N (1,000 kgf, 2,205 lbf). Press the adjuster rod as far as the end surface of the cylinder. Do not press the adjuster rod into cylinder. Doing so may damage the cylinder. Do not release the press pressure until stopper pin is completely inserted. Attach the automatic belt tension adjuster assembly to the vertical pressing tool. Slowly move the adjuster rod down with a pressure of more than 294 N (30 kgf, 66 lbf) until the adjuster rod is aligned with the stopper pin hole in the cylinder. (Scheme 106): Attaching Automatic Belt Tension Adjuster Assembly To Vertical Pressing Tool With a 2 mm (0.08 in) dia. stopper pin or a 2 mm (0.08 in) (nominal) dia. hex wrench inserted into the stopper pin hole in cylinder, secure the adjuster rod. (Scheme 107): Inserting Hex Wrench Into Stopper Pin Hole In Cylinder
2. Install the automatic belt tension adjuster assembly. Tightening torque: 39 N.m (4.0 kgf-m, 28.9 ft-lb) (Scheme 108): Identifying Automatic Belt Tension Adjuster Assembly
3. Install the belt idler (No. 1). Tightening torque: 39 N.m (4.0 kgf-m, 28.9 ft-lb) (Scheme 109): Identifying Belt Idler (No. 1)

Scheme 129

Scheme 130

Scheme 131

Scheme 132

Scheme 133

Scheme 134

1. Prepare for installation of automatic belt tension adjuster assembly. < Ref. to «AUTOMATIC BELT TENSION ADJUSTER ASSEMBLY AND BELT IDLER»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), INSTALLATION, Timing Belt. >
2. Installation of timing belt Turn the cam sprocket No. 2 using ST1, and turn the cam sprocket No. 1 using ST2 so that their alignment marks (A) come to top positions. ST1 18231AA010 CAM SPROCKET WRENCH NOTE: CAM SPROCKET WRENCH (499207100) can also be used. ST2 499207400 CAM SPROCKET WRENCH (Scheme 110): Identifying Alignment Marks On Cam Sprocket While aligning the alignment mark (B) on timing belt with the mark (A) on sprockets, position the timing belt properly. (Scheme 111): Identifying Aligning Alignment Mark (B) On Timing Belt
3. Install the belt idler (No. 2). Tightening torque: 39 N.m (4.0 kgf-m, 28.9 ft-lb) see scheme 81: Installing Belt Idler (No. 2)
4. After ensuring the marks on timing belt and cam sprockets are aligned, remove the stopper pin from belt tension adjuster. see scheme 82: Removing Stopper Pin From Belt Tension Adjuster
5. Install the timing belt guide. (MT model) Temporarily tighten the timing belt guide mounting bolts. (Scheme 112): Locating Timing Belt Guide Mounting Bolts Check and adjust the clearance between timing belt and timing belt guide by using thickness gauge. Clearance: 1.0±0.5 mm (0.039±0.020 in) (Scheme 113): Identifying Clearance Between Timing Belt And Timing Belt Guide Tighten the timing belt guide mounting bolts. Tightening torque: 9.75 N.m (1.0 kgf-m, 7.2 ft-lb) (Scheme 114): Tightening Timing Belt Guide Mounting Bolts
6. Install the timing belt cover. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
7. Install the crank pulley. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
8. Install the V-belts. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >

Scheme 135

1. Check the timing belt teeth for breaks, cracks and wear. If any fault is found, replace the belt.
2. Check the condition of the backside of belt. If cracks are found, replace the belt. CAUTION: Be careful not to let oil, grease or coolant contact the belt. Remove quickly and thoroughly if this happens. Do not bend the timing belt sharply. In radial diameter h: 60 mm (2.36 in) or more see scheme 86: Identifying Timing Belt Radial Diameter

Scheme 136

1. Visually check the oil seals for leaks, and rod ends for abnormal wear or scratches. If necessary, replace the automatic belt tension adjuster assembly. NOTE: Slight traces of oil at rod's oil seal does not indicate a problem.
2. Check that the adjuster rod does not move when a pressure of 294 N (30 kgf, 66 lbf) is applied to it. This is to check adjuster rod stiffness.
3. If the adjuster rod is not stiff and moves freely when applying 294 N (30 kgf, 66 lbf), check it using the following procedures: Slowly press the adjuster rod down to the end surface of the cylinder. Repeat this operation two to three times. With the adjuster rod moved all the way up, apply a pressure of 294 N (30 kgf, 66 lbf) to it. Check the adjuster rod stiffness. If the adjuster rod is not stiff and moves down, replace the automatic belt tension adjuster assembly with a new one. CAUTION: Always use a vertical type pressing tool to move the adjuster rod down. Do not use a lateral type vise. Push the adjuster rod vertically. Press the adjuster rod gradually taking more than three minutes. Do not allow press pressure to exceed 9,807 N (1,000 kgf, 2,205 lbf). Press the adjuster rod as far as the end surface of cylinder. Do not press the adjuster rod into cylinder. Doing so may damage the cylinder.
4. Measure the amount of rod protrusion beyond the body. If it is not within specifications, replace with a new one. Amount of rod protrusion H: 5.7±0.5 mm (0.224±0.020 in) see scheme 87: Measuring Amount Of Rod Protrusion

BELT TENSION PULLEY

1. Check the mating surfaces of timing belt and contact point of adjuster rod for abnormal wear or scratches. Replace the automatic belt tension adjuster assembly if faulty.
2. Check the belt tension pulley for smooth rotation. Replace if noise or excessive play occurs.
3. Check the belt tension pulley for grease leakage.

BELT IDLER

1. Check the belt idler for smooth rotation. Replace if noise or excessive play occurs.
2. Check the outer contacting surfaces of idler pulley for abnormal wear and scratches.
3. Check the belt idler for grease leakage.

Scheme 137

Scheme 138

1. Remove the V-belts. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
3. Remove the timing belt cover. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
4. Remove the timing belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
5. Remove the camshaft position sensor. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Camshaft Position Sensor. >
6. Remove the cam sprocket No. 2. To lock the camshaft, use ST. ST 18231AA010 CAM SPROCKET WRENCH NOTE: CAM SPROCKET WRENCH (499207100) can also be used. (Scheme 115): Removing Cam Sprocket No. 2 Using Cam Sprocket Wrench ST (18231AA010)
7. Remove the cam sprocket No. 1. To lock the camshaft, use ST. ST 499207400 CAM SPROCKET WRENCH (Scheme 116): Removing Cam Sprocket No. 1 Using Cam Sprocket Wrench ST (499207400)

1. Install the cam sprocket No. 1. To lock the camshaft, use ST. ST 499207400 CAM SPROCKET WRENCH Tightening torque: 78 N.m (8.0 kgf-m, 57.9 ft-lb) NOTE: Do not confuse left and right side cam sprockets during installation. Identify by indication of L or R. (Scheme 117): Installing Cam Sprocket No. 1 Using Cam Sprocket Wrench ST (499207400)
2. Install the cam sprocket No. 2. To lock the camshaft, use ST. ST 18231AA010 CAM SPROCKET WRENCH NOTE: CAM SPROCKET WRENCH (499207100) can also be used. Tightening torque: 78 N.m (8.0 kgf-m, 57.9 ft-lb) (Scheme 118): Installing Cam Sprocket No. 2 Using Cam Sprocket Wrench ST (18231AA010)
3. Install the camshaft position sensor. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Camshaft Position Sensor. >
4. Install the timing belt. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
5. Install the timing belt cover. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
6. Install the crank pulley. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
7. Install the V-belts. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >

1. Check the cam sprocket teeth for abnormal wear and scratches.
2. Make sure there is no free play between cam sprocket and key.
3. Check the cam sprocket protrusion used for sensor for damage and contamination of foreign matter.

Scheme 139

1. Remove the V-belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
3. Remove the timing belt cover. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
4. Remove the timing belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
5. Remove the crank sprocket. (Scheme 119): Identifying Crank Sprocket

1. Install the crank sprocket. (Scheme 120): Identifying Crank Sprocket
2. Install the timing belt. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
3. Install the timing belt cover. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
4. Install the crank pulley. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
5. Install the V-belts. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >

1. Check the crank sprocket teeth for abnormal wear and scratches.
2. Make sure there is no free play between crank sprocket and key.
3. Check the crank sprocket protrusion used for sensor for damage and contamination of foreign matter.

Scheme 140

Scheme 141

Scheme 142

Scheme 143

1. Remove the V-belts. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
3. Remove the timing belt cover. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
4. Remove the timing belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
5. Remove the cam sprocket. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
6. Disconnect the PCV hose and remove the rocker cover.
7. Remove the valve rocker assembly. Using ST, rotate the spring stopper in the arrow direction to remove it from adjuster pin. ST 18258AA000 SPRING INSTALLER (Scheme 121): Identifying Special Tool (Scheme 122): Rotating Spring Stopper Using Spring Installer ST (18258AA000) Remove the bolts (a) through (j) in alphabetical sequence. NOTE: Leave two or three threads of bolts (i) and (j) engaged in order to retain the valve rocker assembly. (Scheme 123): Identifying Alphabetical Sequence Of Bolts Remove the valve rocker assembly. NOTE: Set the ST in the position shown in the figure to remove the intake valve rocker assembly. ST 18354AA000 VALVE ROCKER HOLDER (Scheme 124): Identifying Valve Rocker Assembly

Scheme 144

Scheme 145

Scheme 146

Scheme 147

1. Install the valve rocker assembly. Temporarily tighten the bolts equally in alphabetical order. NOTE: Do not temporarily tighten the bolts (i) and (j). Set the ST in the position shown in the figure to install the intake valve rocker assembly. ST 18354AA000 VALVE ROCKER HOLDER (Scheme 125): Identifying Valve Rocker Assembly Tighten the bolts (a) through (h) to specified torque. Tightening torque: 25 N.m (2.5 kgf-m, 18.4 ft-lb) Tighten the bolts (i) through (j) to specified torque. Tightening torque: 8 N.m (0.8 kgf-m, 5.9 ft-lb) (Scheme 126): Identifying Alphabetical Sequence Of Bolts Using ST, rotate the spring stopper in the arrow direction to secure it to adjuster pin. ST 18258AA000 SPRING INSTALLER (Scheme 127): Identifying Special Tool (Scheme 128): Rotating Spring Stopper Using Spring Installer ST (18258AA000)
2. Adjust the valve clearance. < Ref. to «ADJUSTMENT»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__adjustment), Valve Clearance. >
3. Tighten the bolts of rocker cover and rocker cover gasket in alphabetical order shown in the figure, and connect the PCV hose. NOTE: Use new rocker cover gasket. Tighten bolts in two stages in alphabetical sequence as shown in the figure. Tightening torque: 1st 6.4 N.m (0.65 kgf-m, 4.7 ft-lb) 2nd 6.4 N.m (0.65 kgf-m, 4.7 ft-lb) RH side see scheme 102: Identifying Alphabetical Sequence Of Bolts - RH Side LH side (Scheme 129): Identifying Alphabetical Sequence Of Bolts - LH Side
4. Install the cam sprocket. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
5. Install the timing belt. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
6. Install the timing belt cover. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
7. Install the crank pulley. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
8. Install the V-belt. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >

DISASSEMBLY

Note. Intake valve rocker assembly can not be disassembled.

1. Remove the exhaust valve rocker arm from rocker shaft. NOTE: Keep all the removed parts in order for re-installing in their original positions.
2. Remove the nut and adjusting screw from valve rocker.

ASSEMBLY

Note. Intake valve rocker assembly can not be disassembled.

1. Install the adjusting screw and nut to exhaust valve rocker arm.
2. Insert the valve rocker arm into rocker shaft. NOTE: Valve rocker arms and rocker shaft have identification marks. Ensure the parts with same markings are properly assembled.

INTAKE VALVE ROCKER ASSEMBLY

1. If the roller or valve contact surface of valve rocker arm is worn or dented excessively, replace the valve rocker assembly.
2. Check that the valve rocker arm roller rotates smoothly. If not, replace the valve rocker assembly.

Scheme 148

Scheme 149

1. Measure the inner diameter of valve rocker arm and outer diameter of valve rocker shaft, and make sure the difference (oil clearance) between the two values. Clearance between arm and shaft: Standard: 0.020 - 0.054 mm (0.0008 - 0.0021 in) Limit: 0.10 mm (0.0039 in) (Scheme 130): Measuring Inner Diameter Of Valve Rocker Arm see scheme 105: Measuring Outer Diameter Of Valve Rocker Shaft
2. If the oil clearance exceeds the limit, replace the valve rocker arm or shaft, whichever shows greater amount of wear. Rocker arm inside diameter: 22.020 - 22.041 mm (0.8669 - 0.8678 in) Rocker shaft diameter: 21.987 - 22.000 mm (0.8656 - 0.8661 in)
3. If the cam or valve contact surface of valve rocker arm is worn or dented excessively, replace the valve rocker arm.
4. Check that the valve rocker arm roller rotates smoothly. If not, replace the valve rocker arm.

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

1. Remove the V-belts. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
3. Remove the timing belt cover. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
4. Remove the timing belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
5. Remove the cam sprocket. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
6. Remove the timing belt cover No. 2 (LH).
7. Remove the timing belt cover No. 2 (RH). NOTE: Do not damage or lose the seal rubber when removing the timing belt covers. (Scheme 131): Identifying Timing Belt Seal Cover
8. Remove the tensioner bracket. (Scheme 132): Identifying Tensioner Bracket
9. Remove the camshaft position sensor support. (LH side only)
10. Remove the oil level gauge guide. (LH side only)
11. Remove the valve rocker assembly. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Valve Rocker Assembly. >
12. Remove the camshaft cap. Remove the bolts (a) and (b) in alphabetical sequence. (Scheme 133): Identifying Alphabetical Sequence Of Bolts Equally loosen the bolts (c) through (j) all the way in alphabetical sequence. (Scheme 134): Identifying Alphabetical Loosening Sequence Of Bolts Remove the bolts (k) through (p) in alphabetical sequence using ST. ST 499497000 TORX PLUS® (Scheme 135): Identifying Alphabetical Removing Sequence Of Bolts Remove the camshaft cap.
13. Remove the camshaft.
14. Remove the oil seal.
15. Remove the plug from the rear side of camshaft.

Scheme 155

Scheme 156

Scheme 157

Scheme 158

Scheme 159

Scheme 160

Scheme 161

Scheme 162

Scheme 163

Scheme 164

1. Apply a coat of engine oil to camshaft journals and install the camshaft.
2. Install the camshaft cap. Apply liquid gasket to the mating surfaces of camshaft cap. Liquid gasket: THREE BOND 1280B (Part No. K0877YA018) (Scheme 136): Applying Liquid Gasket To Mating Surfaces Of Camshaft Cap NOTE: Apply a coat of liquid gasket of 3 mm (0.12 in) in diameter (A) along the edge (B) of camshaft cap (C) mating surface. Assemble them within 20 min. after applying liquid gasket. (Scheme 137): Identifying Area For Applying Liquid Gasket Temporarily tighten the bolts (a) through (d) in alphabetical sequence. (Scheme 138): Identifying Alphabetical Tighten Sequence Of Bolts Install the valve rocker assembly. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Valve Rocker Assembly. > Tighten the TORX® bolts (e) through (j) in alphabetical sequence using ST. ST 499497000 TORX PLUS® Tightening torque: 18 N.m (1.8 kgf-m, 13.3 ft-lb) see scheme 114: Identifying Torx Bolts Alphabetical Sequence Of Bolts Tighten the bolts (k) through (r) in alphabetical sequence. Tightening torque: 9.75 N.m (1.0 kgf-m, 7.2 ft-lb) see scheme 115: Identifying Alphabetical Tighten Sequence Of Bolts Tighten the bolts (s) and (t) in alphabetical sequence. Tightening torque: 9.75 N.m (1.0 kgf-m, 7.2 ft-lb) (Scheme 139): Identifying Alphabetical Tighten Sequence Of Bolts
3. Apply a coat of grease to oil seal lips and install the oil seal (A) on camshaft using ST1 and ST2. NOTE: Use a new oil seal. ST1 499597000 OIL SEAL GUIDE ST2 499587500 OIL SEAL INSTALLER see scheme 117: Installing Oil Seal Using Oil Seal Installer ST2 (499587500)
4. Install the plug (A) using ST. ST 499587700 CAMSHAFT OIL SEAL INSTALLER (Scheme 140): Installing Plug Using Camshaft Oil Seal Installer ST (499587700)
5. Adjust the valve clearance. < Ref. to «ADJUSTMENT»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__adjustment), Valve Clearance. >
6. Tighten the bolts of rocker cover and rocker cover gasket in alphabetical order shown in the figure, and connect the PCV hose. NOTE: Use new rocker cover gasket. Tighten bolts in two stages in alphabetical sequence as shown in the figure. Tightening torque: 1st 6.4 N.m (0.65 kgf-m, 4.7 ft-lb) 2nd 6.4 N.m (0.65 kgf-m, 4.7 ft-lb) RH side (Scheme 141): Identifying Alphabetical Tighten Sequence Of Bolts - RH Side LH side (Scheme 142): Identifying Alphabetical Tighten Sequence Of Bolts - LH Side
7. Install the oil level gauge guide. (LH side)
8. Install the camshaft position sensor support. (LH side)
9. Install the tensioner bracket. Tightening torque: 24.5 N.m (2.5 kgf-m, 18.1 ft-lb) (Scheme 143): Identifying Tensioner Bracket
10. Install the timing belt cover No. 2 (RH). Tightening torque: 5 N.m (0.5 kgf-m, 3.6 ft-lb)
11. Install the timing belt cover No. 2 (LH). Tightening torque: 5 N.m (0.5 kgf-m, 3.6 ft-lb) see scheme 122: Identifying Timing Belt Cover No. 2 (LH)
12. Install the cam sprocket. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
13. Install the timing belt. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
14. Install the timing belt cover. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
15. Install the crank pulley. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
16. Install the V-belt. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >

Scheme 165

Scheme 166

1. Measure the bend, and repair or replace if necessary. Service limit: 0.025 mm (0.0098 in) (Scheme 144): Measuring Camshaft Bend
2. Check the journal for damage and wear. Replace if faulty.
3. Measure the outer diameter of camshaft journal and inner diameter of cylinder head journal, and make sure the difference (oil clearance) between the two values. If the oil clearance exceeds standard value, replace the camshaft or cylinder head as necessary. OIL CLEARANCE SPECIFICATION CHART Unit: mm (in) Oil clearance Standard 0.055 - 0.090 (0.0022 - 0.0035) Limit 0.10(0.0039) Camshaft journal O.D. 31.928 - 31.945 (1.2570 - 1.2577) Journal hole I.D. 32.000 - 32.018 (1.2598 - 1.2605)
4. Check the cam face condition, and remove the minor faults by grinding with oil stone. Measure the cam height H. If it exceeds the limit, replace it. Cam height H: CAM HEIGHT (H) SPECIFICATION CHART Parts Unit: mm (in) Intake Fixed Standard 40.075 - 40.175 (1.5778 - 1.5817) Limit 39.975 (1.5738) Low speed Standard 35.182 - 35.282 (1.3851 - 1.3891) Limit 35.082 (1.3812) High speed Standard 40.315 - 40.415 (1.5872 - 1.5911) Limit 40.215 (1.5833) Exhaust Standard 40.149 - 40.249 (1.5807 - 1.5846) Limit 40.049(1.5767) Cam base circle diameter A: Intake: 34.00 mm (1.3386 in) Exhaust: 34.00 mm (1.3386 in) Difference between base circles of adjacent intake cams (low speed and high speed): 0.03 mm (0.001 in) or less see scheme 124: Measuring Cam Height
5. Measure the thrust clearance of camshaft with setting the dial gauge at end of camshaft. If the thrust clearance exceeds the limit, replace the camshaft cap and cylinder head as a set. If necessary, replace the camshaft. Standard: 0.030 - 0.090 mm (0.0012 - 0.0035 in) Limit: 0.10 mm (0.0039 in)

Scheme 167

1. Remove the V-belts. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
2. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
3. Remove the timing belt cover. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
4. Remove the timing belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
5. Remove the cam sprocket. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
6. Remove the intake manifold. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Intake Manifold. >
7. Remove the bolt which installs the A/C compressor bracket on cylinder head.
8. Remove the valve rocker assembly. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Valve Rocker Assembly. >
9. Remove the camshaft. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Camshaft. >
10. Remove the cylinder head bolts in alphabetical sequence as shown in the figure. NOTE: Leave bolts (a) and (c) engaged by three or four threads to prevent the cylinder head from falling. (Scheme 145): Identifying Cylinder Head Bolts Removing Sequence In Alphabetical Order
11. While tapping the cylinder head with a plastic hammer, separate it from cylinder block.
12. Remove the bolts (a) and (c) to remove the cylinder head. (Scheme 146): Identifying Cylinder Head Bolts Alphabetical Sequence
13. Remove the cylinder head gasket. CAUTION: Be careful not to scratch the mating surface of cylinder head and cylinder block.
14. Similarly, remove the right side cylinder head.

Scheme 168

1. Install the cylinder head and gaskets on cylinder block. CAUTION: Use new cylinder head gaskets. Be careful not to scratch the mating surface of cylinder block and cylinder head.
2. Tighten the cylinder head bolts. Apply a coat of engine oil to washers and bolt threads. Tighten all bolts to 29 N.m (3.0 kgf-m, 21.4 ft-lb) in alphabetical sequence. Then tighten all bolts to 69 N.m (7.0 kgf-m, 50.9 ft-lb) in alphabetical sequence. Back off all bolts by 180° in reverse order of installation, and back them off again by 180°. Tighten all bolts to 42 N.m (4.3 kgf-m, 31 ft-lb) in alphabetical sequence. Tighten all bolts by 80° - 90° in alphabetical sequence. Tighten all bolts by 40° - 45° in alphabetical sequence. CAUTION: Tightening angle of the bolt must not exceed 45°. Further tighten bolts (a) and (b) by 40° - 45°. CAUTION: Total "re-tightening angle" of the step (6) and (7) must not exceed 90°. (Scheme 147): Identifying Cylinder Head Bolts Alphabetical Sequence
3. Install the camshaft. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Camshaft. >
4. Install the valve rocker assembly. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Valve Rocker Assembly. >
5. Install the A/C compressor bracket on cylinder head.
6. Install the intake manifold. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Intake Manifold. >
7. Install the cam sprocket. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
8. Install the timing belt. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
9. Install the timing belt cover. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
10. Install the crank pulley. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
11. Install the V-belts. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >

Scheme 169

1. Place the cylinder head on the ST. ST 498267800 CYLINDER HEAD TABLE
2. Set the ST on valve spring. Compress the valve spring and remove the valve spring retainer key. Remove each valve and valve spring. ST 499718000 VALVE SPRING REMOVER NOTE: Keep all the removed parts in order for re-installing in their original positions. Mark each valve to prevent confusion. Use extreme care not to damage the lips of the intake valve oil seals and exhaust valve oil seals. (Scheme 148): Setting ST On Valve Spring

Scheme 170

Scheme 171

1. Installation of valve spring and valve: Place the cylinder head on the ST. ST 498267800 CYLINDER HEAD TABLE Coat the stem of each valve with engine oil and insert the valve into valve guide. CAUTION: Use extreme care not to damage the oil lips when inserting the valve into valve guide. Install the valve spring and retainer. NOTE: Be sure to install the valve springs with their close-coiled end facing the seat on the cylinder head. Set the ST on valve spring. ST 499718000 VALVE SPRING REMOVER (Scheme 150): Installing Valve Spring And Retainer Using Valve Spring Remover ST (499718000) Compress the valve spring, and then fit the valve spring retainer and valve spring retainer key. (Scheme 151): Identifying Valve Spring And Retainer After installing, tap the valve spring retainers lightly with a plastic hammer for better seating.

Scheme 172

1. Make sure that no crack or other damage do not exist. In addition to visual inspection, inspect important areas by means of liquid penetrant tester. Also make sure the gasket installing surface shows no trace of gas and water leaks.
2. Place the cylinder head on the ST. ST 498267800 CYLINDER HEAD TABLE
3. Measure the warping of the cylinder head surface that mates with crankcase using a straight edge and thickness gauge. If the warping exceeds the limit, regrind the surface with a surface grinder. Warping limit: 0.03 mm (0.0012 in) Grinding limit: 0.1 mm (0.004 in) Standard height of cylinder head: 97.5 mm (3.84 in) NOTE: Uneven torque for the cylinder head bolts can cause warping. When reassembling, pay special attention to the torque so as to tighten evenly. (Scheme 152): Measuring Warping Of Cylinder Head Surface Using Straight Edge And Thickness Gauge

VALVE SEAT

Inspect the intake and exhaust valve seats, and correct the contact surfaces with a valve seat cutter if they are defective or when valve guides are replaced.

Valve seat width W

Standard

Intake (A)

0.8 - 1.4 mm (0.03 - 0.055 in)

Exhaust (B)

1.2 - 1.8 mm (0.047 - 0.071 in)

Limit

Intake (A)

1.7 mm (0.067 in)

Exhaust (B)

2.2 mm (0.087 in)

Scheme 173

Scheme 174

Scheme 175

Scheme 176

Scheme 177

Scheme 178

Scheme 179

Scheme 180

Scheme 181

1. Check the clearance between valve guide and stem. The clearance can be checked by measuring respectively the outer diameter of valve stem with a micrometer and inner diameter of valve guide with a caliper gauge. Clearance between the valve guide and valve stem: Standard Intake 0.035 - 0.062 mm (0.0014 - 0.0024 in) Exhaust 0.040 - 0.067 mm (0.0016 - 0.0026 in) Limit 0.15 mm (0.059 in) (Scheme 155): Checking Clearance Between Valve Guide And Stem (Scheme 156): Measuring Outer Diameter Of Valve Stem With Micrometer
2. If the clearance between valve guide and stem exceeds the standard value, replace the valve guide or valve itself whichever shows greater amount of wear. See the following procedure for valve guide replacement. Valve guide inner diameter: 6,000 - 6.012 mm (0.2362 - 0.2367 in) Valve stem outer diameters: Intake 5.950 - 5.965 mm (0.2343 - 0.2348 in) Exhaust 5.945 - 5.960 mm (0.2341 - 0.2346 in) Place the cylinder head on ST1 with the combustion chamber upward so that valve guides enter the holes in ST1. Insert ST2 into the valve guide and press it down to remove the valve guide. ST1 498267800 CYLINDER HEAD TABLE ST2 499767200 VALVE GUIDE REMOVER (Scheme 157): Inserting ST2 Into Valve Guide Using Valve Guide Remover ST2 (499767200) Turn the cylinder head upside down and place the ST as shown in the figure. Intake side: ST 499767700 VALVE GUIDE ADJUSTER Exhaust side: ST 499767800 VALVE GUIDE ADJUSTER (Scheme 158): [Sectional View Of Valve Guide] Before installing a new valve guide, make sure that neither scratches nor damages exist on the inside surface of the valve guide holes in cylinder head. Put a new valve guide, coated with sufficient oil, in cylinder, and insert the ST1 into valve guide. Press in until the valve guide upper end is flush with the upper surface of ST2. ST1 499767200 VALVE GUIDE REMOVER Intake side: ST2 499767700 VALVE GUIDE ADJUSTER Exhaust side: ST2 499767800 VALVE GUIDE ADJUSTER (Scheme 159): Inserting ST1 Into Valve Guide Using Valve Guide Remover ST1 (499767200) Check the valve guide protrusion. Valve guide protrusion L: Intake 20.0 - 21.0 mm (0.787- 0.827 in) Exhaust 16.5 - 17.5 mm (0.650 - 0.689 in) (Scheme 160): Identifying Valve Guide Protrusion Ream the inside of valve guide using ST. Put the reamer in valve guide, and rotate the reamer slowly clockwise while pushing it lightly. Bring the reamer back while rotating it clockwise. After reaming, clean the valve guide to remove chips. CAUTION: Apply engine oil to the reamer when reaming. If the inner surface of the valve guide is torn, the edge of the reamer should be slightly ground with an oil stone. If the inner surface of the valve guide becomes lustrous and the reamer does not chip, use a new reamer or remedy the reamer. ST 499767400 VALVE GUIDE REAMER (Scheme 161): Reaming Inside Of Valve Guide Using ST Recheck the contact condition between valve and valve seat after replacing the valve guide.

Scheme 182

1. Inspect the flange and stem of valve, and replace if damaged, worn or deformed, or if "H" exceed the standard value. H: Intake Standard: 0.8 - 1.2 mm (0.03 - 0.047 in) Limit: 0.6 mm (0.024 in) Exhaust Standard: 1.0 - 1.4 mm (0.039 - 0.055 in) Limit: 0.6 mm (0.024 in) Valve overall length: Intake 120.6 mm (4.75 in) Exhaust 121.7 mm (4.79 in) (Scheme 162): Identifying Intake And Exhaust Valve Dimension
2. Put a small amount of grinding compound on the seat surface and lap the valve and seat surface. < Ref. to «VALVE SEAT»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so__valve-seat), INSPECTION, Cylinder Head. > Install a new intake valve oil seal after lapping.

Scheme 183

1. Check the valve springs for damage, free length, and tension. Replace the valve spring if it is not within the standard value presented in the table.
2. To measure the squareness of the valve spring, stand the spring on a surface plate and measure its deflection at the top of spring using a try square. VALVE SPRING SPECIFICATION CHART Free length mm (in) 55.2(2.173) Squareness 2.5°, 2.4 mm (0.094 in) or less Tension/spring height Set 235.3 - 270.7 (24 - 27.6, 52.9 - 60.8)/45.0 (1.772) N (kgf, lbf)/mm (in) Lift 578.9 - 639.9(59.1-65.3, 130.3 - 143.9)/34.7(1.366) see scheme 143: Measuring Squareness Of Valve Spring

INTAKE AND EXHAUST VALVE OIL SEAL

In the following case, pinch and remove the oil seal from valve using pliers, and then replace it with a new one.

1. When the lip is damaged.
2. When the spring is out of the specified position.
3. When readjusting the surfaces of intake valve and valve sheet.
4. When replacing the intake valve guide.

Scheme 184

1. Place the cylinder head on ST1.
2. Using ST2, press-fit the oil seal. CAUTION: Apply engine oil to oil seal before press-fitting. When press-fitting the oil seal, do not use a hammer or strike in. Differentiate between the intake valve oil seal and exhaust valve oil seal by noting their difference in color. ST1 498267800 CYLINDER HEAD TABLE ST2 498857100 VALVE OIL SEAL GUIDE Color of rubber part: Intake [Gray] Exhaust [Green] see scheme 144: Pressing Oil Seal Using ST2

Note. Before conducting this procedure, drain the engine oil completely.

Scheme 185

Scheme 186

Scheme 187

Scheme 188

Scheme 189

Scheme 190

Scheme 191

Scheme 192

Scheme 193

Scheme 194

Scheme 195

Scheme 196

Scheme 197

Scheme 198

1. Remove the intake manifold. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Intake Manifold. >
2. Remove the V-belts. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
3. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
4. Remove the timing belt cover. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
5. Remove the timing belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
6. Remove the cam sprocket. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
7. Remove the crank sprocket. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
8. Remove the generator and A/C compressor with their brackets.
9. Remove the rocker cover.
10. Remove the cylinder head bolts in alphabetical sequence as shown in the figure. NOTE: Leave bolts (a) and (d) engaged by three or four threads to prevent the cylinder head from falling. (Scheme 163): Identifying Cylinder Head Bolts In Alphabetical Sequence
11. While tapping the cylinder head with a plastic hammer, separate it from cylinder block.
12. Remove the bolts (a) and (d) to remove the cylinder head. (Scheme 164): Identifying Cylinder Head Bolts In Alphabetical Sequence
13. Remove the cylinder head gasket. NOTE: Do not scratch the mating surface of cylinder head and cylinder block.
14. Similarly, remove the right side cylinder head.
15. Remove the clutch housing cover. (MT model)
16. Remove the flywheel (MT model) or drive plate (AT model). Lock the crankshaft using ST. ST 498497100 CRANKSHAFT STOPPER MT model (Scheme 165): Locking Crankshaft Using Crankshaft Stopper ST (498497100)- MT Model AT model (Scheme 166): Locking Crankshaft Using Crankshaft Stopper ST (498497100)- AT Model
17. Remove the oil separator cover.
18. Remove the water bypass pipe for heater.
19. Remove the water pump after loosening the bolts in alphabetical sequence as shown in the figure. (Scheme 167): Identifying Water Pump Bolts Loosening Sequence In Alphabetical Order
20. Remove the bolts which install the oil pump onto cylinder block. NOTE: If disassembling or inspecting the oil pump, loosen the plug of relief valve before removing the oil pump. see scheme 150: Identifying Oil Pump Relief Valve
21. Remove the oil pump from cylinder block. Use a flat tip screwdriver when removing the oil pump. CAUTION: Be careful not to scratch the mating surface of cylinder block and oil pump. (Scheme 168): Removing Oil Pump From Cylinder Block Using Screwdriver
22. Remove the oil pan. Place the cylinder block to face the #2 and #4 piston side upward. Remove the bolts which secure oil pan to cylinder block. Insert a oil pan cutter blade between cylinder block-to-oil pan clearance and remove the oil pan. NOTE: Do not use a screwdriver or similar tools in place of oil pan cutter.
23. Remove the oil strainer stay.
24. Remove the oil strainer.
25. Remove the baffle plate.
26. Remove the oil filter using ST. ST 18332AA000 OIL FILTER WRENCH (Outer diameter: 68 mm (2.68 in)) ST 18332AA010 OIL FILTER WRENCH (Outer diameter: 65 mm (2.56 in)) NOTE: Standard oil filter is outer diameter of 68 mm (2.68 in). However, SUBARU genuine oil filter having outer diameter of 65 mm (2.56 in) can also be used. (Scheme 169): Removing Oil Filter
27. Remove the water pipe. (Scheme 170): Identifying Water Pipe see scheme 154: Identifying Cylinder Block Components
28. Remove the service hole cover and service hole plugs using a hexagon wrench (14 mm). (Scheme 171): Removing Service Hole Cover And Service Hole Plugs Using Hexagon Wrench
29. Rotate the crankshaft to bring #1 and #2 pistons to bottom dead center position, then remove the piston snap ring through service hole of #1 and #2 cylinders. (Scheme 172): Removing Piston Snap Ring
30. Draw out the piston pin from #1 and #2 pistons using ST. ST 499097700 PISTON PIN REMOVER ASSY NOTE: Be careful not to confuse the original combination of piston, piston pin and cylinder. (Scheme 173): Drawing Out Piston Pin From Pistons
31. Similarly remove the piston pins from #3 and #4 pistons.
32. Remove the bolts which connect cylinder block on the side of #2 and #4 cylinders.
33. Back off the bolts which connect cylinder block on the side of #1 and #3 cylinders two or three turns.
34. Set up the cylinder block so that #1 and #3 cylinders are on the upper side, then remove the cylinder block connecting bolts.
35. Separate the cylinder block (RH) and (LH). NOTE: When separating the cylinder block, do not allow the connecting rod to fall or damage the cylinder block. (Scheme 174): Identifying Cylinder Block Components
36. Remove the rear oil seal.
37. Remove the crankshaft together with connecting rod.
38. Remove the crankshaft bearings from cylinder block using a hammer handle. NOTE: Be careful not to confuse the crankshaft bearing combination. Press the bearing at the end opposite to locking lip.
39. Draw out each piston from cylinder block using a wooden bar or hammer handle. NOTE: Be careful not to confuse the original combination of piston and cylinder.

Scheme 199

Note. Remove oil on the mating surface of bearing and cylinder block before installation. Apply a coat of engine oil to crankshaft pins.

Scheme 200

Scheme 201

Scheme 202

Scheme 203

Scheme 204

Scheme 205

Scheme 206

Scheme 207

Scheme 208

Scheme 209

Scheme 210

Scheme 211

Scheme 212

Scheme 213

Scheme 214

Scheme 215

Scheme 216

Scheme 217

Scheme 218

Scheme 219

Scheme 220

Scheme 221

Scheme 222

Scheme 223

1. Position the crankshaft on the #2 and #4 cylinder block.
2. Apply liquid gasket to the mating surface of #1 and #3 cylinder block, and position it on #2 and #4 cylinder block. Liquid gasket: THREE BOND 1215 (Part No. 004403007) or equivalent NOTE: Do not allow liquid gasket to flow into O-ring grooves, oil passages, bearing grooves, etc. (Scheme 176): Applying Liquid Gasket To Mating Surface Of Cylinder Block
3. Apply engine oil to washers and thread of bolts.
4. Tighten the 10 mm cylinder block connecting bolts on LH side (A - D) in alphabetical sequence. Tightening torque: 10 N.m (1.0 kgf-m, 7.4 ft-lb) (Scheme 177): Identifying Cylinder Block Connecting Bolt Alphabetical Sequence
5. Tighten the 10 mm cylinder block connecting bolts on RH side (E - J) in alphabetical sequence. Tightening torque: 10 N.m (1.0 kgf-m, 7.4 ft-lb) (Scheme 178): Identifying Cylinder Block Connecting Bolts Tightening Sequence In Alphabetical Order
6. Further tighten the LH side bolts (A - D) in alphabetical sequence. Tightening torque: 18 N.m (1.8 kgf-m, 13.3 ft-lb) (Scheme 179): Identifying Cylinder Block Connecting Bolt Alphabetical Sequence
7. Further tighten the RH side bolts (E - J) in alphabetical sequence. Tightening torque: 18 N.m (1.8 kgf-m, 13.3 ft-lb) (Scheme 180): Identifying Cylinder Block Connecting Bolts Tightening Sequence In Alphabetical Order
8. Further tighten the LH side bolts (A), (C) to 90°, (B), (D) to 40 N.m (4.1 kgf-m, 29.5 ft-lb) in alphabetical sequence. (Scheme 181): Identifying Cylinder Block Connecting Bolt Alphabetical Sequence
9. Further tighten the RH side bolts (E - J) to 90° in alphabetical sequence. (Scheme 182): Identifying Cylinder Block Connecting Bolts Tightening Sequence In Alphabetical Order
10. Tighten the 8 mm and 6 mm cylinder block connecting bolts on LH side (A - H) in alphabetical sequence. Tightening torque: (A) - (G): 25 N.m (2.5 kgf-m, 18.4 ft-lb) (H): 6.4 N.m (0.65 kgf-m, 4.7 ft-lb) (Scheme 183): Identifying Cylinder Block Connecting Bolts Tightening Sequence In Alphabetical Order
11. Install the rear oil seal using ST1 and ST2. ST1 499597100 CRANKSHAFT OIL SEAL GUIDE ST2 499587200 CRANKSHAFT OIL SEAL INSTALLER (Scheme 184): Installing Rear Oil Seal Using ST1 And ST2 NOTE: Use a new rear oil seal.
12. Position the top ring gap at (A) or (B) in the figure. NOTE: Assemble the piston ring with stamped mark "R" facing toward upside of piston.
13. Position the second ring gap at 180° on the reverse side of the top ring gap. NOTE: Assemble the piston ring with stamped mark "R" facing toward upside of piston. (Scheme 185): Identifying Ring Gap Position
14. Position the upper rail gap at (C) in the figure. (Scheme 186): Positioning Upper Rail Gap At (C)
15. Align upper rail spin stopper (E) with piston side surface hole (D). (Scheme 187): Identifying Upper Rail Spin Stopper (E) And Piston Side Surface Hole (D)
16. Position the expander gap on the opposite side position (F) 180° away from upper rail gap position (C). (Scheme 188): Identifying Upper Rail Gap Position
17. Position the lower rail gap on the position (G) 120° away from upper rail gap position (C). (Scheme 189): Identifying Lower Rail Gap Position CAUTION: Ensure ring gaps do not face the same direction. Ensure ring gaps are not within the piston skirt area.
18. Install the snap ring. Install snap rings in the piston holes located opposite to the service holes in cylinder block, when positioning all pistons in the corresponding cylinders. NOTE: Use new snap rings. (Scheme 190): Identifying Snap Ring In Piston Holes CAUTION: Piston front mark faces towards the front of engine. (Scheme 191): Identifying Piston Front Mark (Scheme 192): Identifying Cylinder Block Components With Torque Specification
19. Install the piston. Place the cylinder block to face the #1 and #2 cylinder side upward. Using ST1, turn the crankshaft so that #1 and #2 connecting rods are set at bottom dead center. ST1 499987500 CRANKSHAFT SOCKET Apply a coat of engine oil to the pistons and cylinders and insert pistons in their cylinders using ST2. ST2 498747300 PISTON GUIDE (Scheme 193): Inserting Pistons In Cylinders Using ST2
20. Install the piston pin. Apply a coat of engine oil to ST3. Insert ST3 into the service hole to align piston pin hole with connecting rod small end. ST3 499017100 PISTON PIN GUIDE (Scheme 194): Inserting ST3 Into Service Hole To Align Piston Pin Hole With Connecting Rod Small End Apply a coat of engine oil to piston pin, and insert the piston pin into piston and connecting rod through service hole. Install the snap ring. NOTE: Use new snap rings. (Scheme 195): Installing Snap Ring Apply liquid gasket around the service hole plug. Liquid gasket: THREE BOND 1105 (Part No. 004403010) or equivalent (Scheme 196): Applying Liquid Gasket Around Service Hole Plug Install the service hole plug and gasket. NOTE: Use a new gasket. (Scheme 197): Installing Service Hole Plug And Gasket (Scheme 198): Identifying Cylinder Block Components With Torque Specification Tightening torque: N.m (kgf-m, ft-lb) T1: 6.4 (0.65,4.7) T2: 70 (7.1, 50.6) Place the cylinder block to face the #3 and #4 cylinder sides upward. Following the same procedures as used for #1 and #2 cylinders, install the pistons and piston pins.
21. Install the water pipe. (Scheme 199): Identifying Water Pipe
22. Install the baffle plate. Tightening torque: 6.4 N.m (0.65 kgf-m, 4.7 ft-lb)
23. Install the oil strainer and O-ring. Tightening torque: 10 N.m (1.0 kgf-m, 7.4 ft-lb)
24. Install the oil strainer stay.
25. Apply liquid gasket to mating surfaces and install the oil pan. Liquid gasket: THREE BOND 1207C (Part No. 004403012) or equivalent (Scheme 200): Applying Liquid Gasket To Mating Surfaces Of Oil Pan
26. Apply liquid gasket to the mating surfaces and threaded portion of bolt (A) as shown in the figure, and then install the oil separator cover. Liquid gasket: Mating surface THREE BOND 1207C (Part No. 004403012) or equivalent Thread portion of bolt (A) THREE BOND 1324 (Part No. 004403042) or equivalent Tightening torque: 6.4 N.m (0.65 kgf-m, 4.7 ft-lb) (Scheme 201): Applying Liquid Gasket To Mating Surfaces And Threaded Portion Of Bolt (A)
27. Install the flywheel. (MT model) < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/clutches-manual-hydraulic/#clutch-system), Flywheel. > To lock the crankshaft, use the ST. ST 498497100 CRANKSHAFT STOPPER Tightening torque: 72 N.m (7.3 kgf-m, 52.8 ft-lb) (Scheme 202): Locking Crankshaft Using ST
28. Install the drive plate. To lock the crankshaft, use the ST. ST 498497100 CRANKSHAFT STOPPER Tightening torque: 72 N.m (7.3 kgf-m, 52.8 ft-lb) see scheme 187: Locking Crankshaft Using ST
29. Install the housing cover.
30. Installation of oil pump: Discard the front oil seal after removal. Replace with a new one using ST. ST 499587100 OIL SEAL INSTALLER see scheme 188: Installing Oil Seal Using ST Apply liquid gasket to the matching surface of oil pump. Liquid gasket: THREE BOND 1215 (Part No. 004403007) or equivalent see scheme 189: Applying Liquid Gasket To Matching Surface Of Oil Pump Apply a coat of engine oil to the inside of oil seal. see scheme 190: Applying Coat Of Engine Oil To Inside Of Oil Seal Install the oil pump on cylinder block. Be careful not to damage the oil seal during installation. CAUTION: Make sure the oil seal lip is not folded. Do not forget to install the O-ring and seal when installing the oil pump. Apply liquid gasket to the threaded portion of three bolts. Liquid gasket: THREE BOND 1324 (Part No. 004403042) or equivalent Tightening torque: T: 6.4 N.m (0.65 kgf-m, 4.7 ft-lb) (Scheme 203): Applying Liquid Gasket To Threaded Portion Of Three Bolts
31. Install the water pump and gasket. Tightening torque: First: 12 N.m (1.2 kgf-m, 8.7 ft-lb) Second: 12 N.m (1.2 kgf-m, 8.7 ft-lb) CAUTION: Be sure to use a new gasket. When installing the water pump, tighten bolts in two stages in alphabetical sequence as shown in the figure. (Scheme 204): Identifying Tightening Sequence Of Water Pump Bolts In Alphabetical Order
32. Install the water bypass pipe for heater.
33. Install the oil filter using ST. ST 18332AA000 OIL FILTER WRENCH (Outer diameter: 68 mm (2.68 in)) ST 18332AA010 OIL FILTER WRENCH (Outer diameter: 65 mm (2.56 in)) NOTE: Standard oil filter is outer diameter of 68 mm (2.68 in). However, SUBARU genuine oil filter having outer diameter of 65 mm (2.56 in) can also be used. Install the oil filter by turning it by hand, being careful not to damage the seal rubber. Tighten the oil filter 68 mm (2.68 in) in diameter by approx. 1 rotation more after the seal rubber of oil filter comes in contact with cylinder block or oil cooler. If using a torque wrench, tighten it to 14 N.m (1.4 kgf-m, 10.3 ft-lb). Tighten the oil filter 65 mm (2.56 in) in diameter by approx. 2/3 - 3/4 rotation more after the seal rubber of oil filter comes in contact with cylinder block or oil cooler. If using a torque wrench, tighten it to 12 N.m (1.2 kgf-m, 8.7 ft-lb). CAUTION: Do not tighten excessively, or oil may leak.
34. Tighten the cylinder head bolts. Apply a coat of engine oil to washers and bolt threads. Tighten all bolts to 29 N.m (3.0 kgf-m, 22 ft-lb) in alphabetical sequence. Then tighten all bolts to 69 N.m (7.0 kgf-m, 51 ft-lb) in alphabetical sequence. Back off all bolts by 180° in reverse order of installation, and back them off again by 180°. Tighten all bolts to 42 N.m (4.3 kgf-m, 31 ft-lb) in alphabetical sequence. Tighten all bolts by 80 - 90° in alphabetical sequence. Tighten all bolts by 40 - 45° in alphabetical sequence. CAUTION: Tightening angle of the bolt must not exceed 45°. Further tighten the bolts (a) and (b) by 40 - 45°. CAUTION: Total "re-tightening angle" of the step (6) and (7) must not exceed 90°. (Scheme 205): Identifying Tightening Sequence Of Cylinder Head Bolts In Alphabetical Order
35. Install the oil level gauge guide and tighten the bolt. (LH side)
36. Install the rocker cover and rocker cover gasket. NOTE: Use new rocker cover gasket.
37. Install the crank sprocket. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Sprocket. >
38. Install the cam sprocket. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
39. Install the timing belt. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
40. Install the timing belt cover. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
41. Install the crank pulley. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
42. Install the generator and A/C compressor brackets on cylinder head.
43. Install the V-belts. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
44. Install the intake manifold. < Ref. to «INSTALLATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Intake Manifold. >

Scheme 224

1. Remove the connecting rod cap.
2. Remove the connecting rod bearing. NOTE: Arrange the removed connecting rod, connecting rod cap and bearing in order, to prevent confusion.
3. Remove the piston rings using the piston ring expander.
4. Remove the oil ring by hand. NOTE: Arrange the removed piston rings in proper order, to prevent confusion.
5. Remove the snap ring.

Scheme 225

1. Apply oil to the surfaces of the connecting rod bearings.
2. Install the connecting rod bearings on connecting rods and connecting rod caps.
3. Position each connecting rod with the marked side facing forward, and install it.
4. Install the connecting rod cap with connecting rod nut. Ensure the connecting rod side mark faces toward front during installation. CAUTION: Each connecting rod has its own mating cap. Make sure that they are assembled correctly by checking their matching number. When tightening the connecting rod nuts, apply oil on the threads.
5. Install the expander, lower rail and upper rail in this order by hand. Install the second ring and top ring with a piston ring expander.

CYLINDER BLOCK

1. Visually check for cracks and damage. Especially, inspect the important parts by means of liquid penetrant tester.
2. Check the oil passages for clogging.
3. Inspect the cylinder block surface that mates with cylinder head for warping by using a straight edge, and correct by grinding if necessary. Warping limit: 0.025 mm (0.00098 in) Grinding limit: 0.1 mm (0.004 in) Standard height of cylinder block: 201.0 mm (7.91 in)

Scheme 226

Scheme 227

Scheme 228

1. The cylinder bore size is stamped on the cylinder block's front upper surface. NOTE: Measurement should be performed at a temperature of 20°C (68°F). Standard sized pistons are classified into two grades, "A" and "B". These grades should be used as guide lines in selecting a standard piston. Standard diameter: A: 99.505 - 99.515 mm (3.9175 - 3.9179 in) B: 99.495 - 99.505 mm (3.9171 - 3.9175 in) (Scheme 208): Identifying Piston Grade Mark
2. How to measure the inner diameter of each cylinder: Measure the inner diameter of each cylinder in both the thrust and piston pin directions at the heights as shown in the figure, using a cylinder bore gauge. NOTE: Measurement should be performed at a temperature of 20°C (68°F). Taper: Standard 0.015 mm (0.0006 in) Limit 0.050 mm (0.0020 in) Out-of-roundness: Standard 0.010 mm (0.0004 in) Limit 0.050 mm (0.0020 in) (Scheme 209): Measuring Inner Diameter Of Cylinder In Thrust And Piston Pin Directions
3. When the piston is to be replaced due to general or cylinder wear, determine a suitable sized piston by measuring the piston clearance.
4. How to measure the outer diameter of each piston: Measure the outer diameter of each piston at the height as shown in the figure. (Thrust direction) NOTE: Measurement should be performed at a temperature of 20°C (68°F). Piston grade point H: 38.2 mm (1.504 in) Standard A: 99.505 - 99.515 mm (3.9175 - 3.9179 in) B: 99.495 - 99.505 mm (3.9171 - 3.9175 in) 0.25 mm (0.0098 in) oversize 99.745 - 99.765 mm (3.9270 - 3.9278 in) 0.50 mm (0.0197 in) oversize 99.995 - 100.015 mm (3.9368 - 3.9376 in) (Scheme 210): Measuring Outer Diameter Of Piston
5. Calculate the clearance between cylinder and piston. NOTE: Measurement should be performed at a temperature of 20°C (68°F). Cylinder to piston clearance at 20°C (68°F): Standard -0.010 - 0.010 mm (-0.00039 - 0.00039 in) Limit 0.030 mm (0.0012 in)
6. Boring and honing If the value of taper, out-of-roundness, or cylinder-to-piston clearance measured exceeds the standard value or if there is any damage on the cylinder wall, rebore it to use an oversize piston. CAUTION: When any of the cylinders needs reboring, all other cylinders must be bored at the same time, and use oversize pistons. Do not perform boring on one cylinder only. Nor use an oversize piston for one cylinder only. If the cylinder inner diameter exceeds limit after boring and honing, replace the cylinder block. Limit of cylinder inner diameter (diameter): 100.005 mm (3.937 in) NOTE: Immediately after reboring, the cylinder diameter may differ from its real diameter due to temperature rise. Thus, pay attention when measuring the cylinder diameter.

Scheme 229

Scheme 230

Scheme 231

1. Check the pistons and piston pins for damage, cracks and wear, and the piston ring grooves for wear and damage. Replace if defective.
2. Measure the piston-to-cylinder clearance at each cylinder. < Ref. to «CYLINDER AND PISTON»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), INSPECTION, Cylinder Block. > If any of the clearances is not within the standard value, replace the piston. Or bore the cylinder to use an oversize piston.
3. Make sure that the piston pin can be inserted into the piston pin hole with a thumb at 20°C (68°F). Replace if defective. Clearance between piston hole and piston pin: Standard 0.004 - 0.008 mm (0.0002 - 0.0003 in) Limit 0.020 mm (0.0008 in) (Scheme 211): Measuring Inner Diameter Of Piston Hole (Scheme 212): Measuring Piston Pin Diameter
4. Check the snap ring installation groove (A) on the piston for burr. If necessary, remove burr from the groove so that the piston pin can lightly move. (Scheme 213): Identifying Snap Ring Installation Groove
5. Check the piston pin snap ring for distortion, cracks and wear.

Scheme 232

Scheme 233

Scheme 234

1. If the piston ring is broken, damaged or worn, or if its tension is insufficient, or when the piston is replaced, replace the piston ring with a new one of the same size as the piston. CAUTION: Mark is displayed on the end of top and second rings. When installing the rings to the piston, face these marks upward. Oil ring consists of the upper rail, expander and lower rail. Be careful about the direction of rail when installing the oil ring to piston. (Scheme 214): Identifying Piston Rings Marks
2. Clean the piston ring groove and piston ring.
3. Squarely place the piston ring and oil ring in cylinder, and measure the piston ring gap with a thickness gauge. PISTON RING SPECIFICATION CHART Standard mm (in) Limit mm (in) Piston ring closed gap Top ring 0.20 - 0.35 (0.0079 - 0.0138) 1.0(0.039) Second ring 0.37 - 0.52 (0.0144 - 0.0203) 1.0(0.039) Oil ring rail 0.20 - 0.50 (0.0079 - 0.0197) 1.5(0.059) (Scheme 215): Measuring Piston Ring Gap With Thickness Gauge
4. Measure the clearance between piston ring and piston ring groove with a thickness gauge. PISTON RING SPECIFICATION CHART Standard mm (in) Limit mm (in) Clearance between piston ring and piston ring groove Top ring 0.040 - 0.080 (0.0016 - 0.0031) 0.15 (0.0059) Second ring 0.030 - 0.070 (0.0012 - 0.0028) 0.15 (0.0059) (Scheme 216): Measuring Clearance Between Piston Ring And Piston Ring Groove With Thickness Gauge

Scheme 235

Scheme 236

Scheme 237

Scheme 238

1. Replace the connecting rod, if the large or small end thrust surface is damaged.
2. Check for bend or twist using a connecting rod aligner. Replace the connecting rod if the bend or twist exceeds the limit. Limit of bend or twist per 100 mm (3.94 in) in length: 0.10 mm (0.0039 in) see scheme 205: Checking Bend Or Twist Using Connecting Rod Aligner
3. Install the connecting rod fitted with bearing to crankshaft and measure the side clearance (thrust clearance). If side clearance exceeds the limit, replace the connecting rod. Connecting rod side clearance: Standard 0.070 - 0.330 mm (0.0028 - 0.0130 in) Limit 0.4 mm (0.016 in) (Scheme 217): Measuring Connecting Rod Side Clearance
4. Inspect the connecting rod bearing for scar, peeling, seizure, melting, wear, etc.
5. Measure the oil clearance on individual connecting rod bearings by means of plastigage. If any oil clearance is not within the specification, replace the defective bearing with a new one of standard size or undersize as necessary. (See the «BEARING SPECIFICATION»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so) below.) Connecting rod oil clearance: Standard 0.016 - 0.044 mm (0.00063 - 0.0017 in) Limit 0.05 mm (0.0020 in) BEARING SPECIFICATION Unit: mm (in) Bearings Bearing size (Thickness at center) Outer diameter of crank pin Standard 1.492 - 1.501 (0.0587 - 0.0591) 51.984 - 52.000 (2.0466 - 2.0472) 0.03 (0.0012) undersize 1.510 - 1.513 (0.0594 - 0.0596) 51.954 - 51.970 (2.0454 - 2.0461) 0.05 (0.0020) undersize 1.520 - 1.523 (0.0598 - 0.0600) 51.934 - 51.950 (2.0446 - 2.0453) 0.25 (0.0098) undersize 1.620 - 1.623 (0.0638 - 0.0639) 51.734 - 51.750 (2.0368 - 2.0374)
6. Inspect the bushing at connecting rod small end, and replace if worn or damaged. Also measure the piston pin clearance at the connecting rod small end. Clearance between piston pin and bushing: Standard 0 - 0.022 mm (0 - 0.0009 in) Limit 0.030 mm (0.0012 in) see scheme 207: Measuring Piston Pin Clearance At Connecting Rod Small End (Scheme 218): Measuring Piston Pin Diameter
7. Replacement procedure is as follows. Remove the bushing from connecting rod with ST and press. Press the bushing with ST after applying oil on the periphery of bushing. ST 499037100 CONNECTING ROD BUSHING REMOVER & INSTALLER (Scheme 219): Pressing Bushing With ST Make two 3 mm (0.12 in)-holes in bushing. Ream the inside of bushing. After completion of reaming, clean the bushing to remove chips.

Scheme 239

Scheme 240

Scheme 241

1. Clean the crankshaft completely, and check it for cracks using liquid penetrant tester. Replace if faulty.
2. Measure the bend of crankshaft. If it exceeds the limit, repair or replace it. NOTE: If a suitable V-block is not available, install #1 and #5 crankshaft bearing on cylinder block, position the crankshaft on these bearings, and then measure the crankshaft bend using a dial gauge. Crankshaft bend limit: 0.035 mm (0.0014 in) see scheme 210: Measuring Crankshaft Bend Using Dial Gauge
3. Inspect the crank journal and crank pin for wear. If they are not within the specifications, replace the bearing with a suitable (undersize) one, and replace or recondition crankshaft as necessary. When grinding the crank journal or crank pin, finish them to the specified dimensions according to the undersize bearing to be used. Crank pin: Out-of-roundness 0.003 mm (0.0001 in) Cylindrically 0.004 mm (0.0002 in) Grinding limit To 51.750 mm (2.0374 in) dia. Crank journal: Out-of-roundness 0.005 mm (0.0002 in) Cylindrically 0.006 mm (0.0002 in) Grinding limit To 59.750 mm (2.3524 in) dia. see scheme 211: Inspecting Crank Journal And Crank Pin Wear CRANKSHAFT BEARING SPECIFICATION CHART Unit: mm (in) Crank journal outer diameter Crank pin outer diameter #1,#3 #2, #4, #5 Standard Journal O.D. 59.992 - 60.008 (2.3619 - 2.3625) 59.992 - 60.008 (2.3619 - 2.3625) 51.984 - 52.000 (2.0466 - 2.0472) Bearing size (Thickness at center) 1.998 - 2.011 (0.0787 - 0.0792) 2.000 - 2.013 (0.0787 - 0.0793) 1.492 - 1.501 (0.0587 - 0.0591) 0.03(0.0012) undersize Journal O.D. 59.962 - 59.978 (2.3607 - 2.3613) 59.962 - 59.978 (2.3607 - 2.3613) 51.954 - 51.970 (2.0454 - 2.0461) Bearing size (Thickness at center) 2.017 - 2.020 (0.0794 - 0.0795) 2.019 - 2.022 (0.0795 - 0.0796) 1.510 - 1.513 (0.0594 - 0.0596) 0.05 (0.0020) undersize Journal O.D. 59.942 - 59.958 (2.3599 - 2.3605) 59.942 - 59.958 (2.3599 - 2.3605) 51.934 - 51.950 (2.0446 - 2.0453) Bearing size (Thickness at center) 2.027 - 2.030 (0.0798 - 0.0799) 2.029 - 2.032 (0.0799 - 0.0800) 1.520 - 1.523 (0.0598 - 0.0600) 0.25 (0.0098) undersize Journal O.D. 59.742 - 59.758 (2.3520 - 2.3527) 59.742 - 59.758 (2.3520 - 2.3527) 51.734 - 51.750 (2.0368 - 2.0374) Bearing size (Thickness at center) 2.127 - 2.130 (0.0837 - 0.0839) 2.129 - 2.132 (0.0838 - 0.0839) 1.620-1.623 (0.0638 - 0.0639)
4. Measure the side clearance of crankshaft at center bearing. If clearance exceeds the limit, replace the bearing. Crankshaft side clearance: Standard 0.030 - 0.115 mm (0.0012 - 0.0045 in) Limit 0.25 mm (0.0098 in) (Scheme 220): Measuring Side Clearance Of Crankshaft At Center Bearing
5. Inspect individual crankshaft bearings for signs of flaking, seizure, melting and wear.
6. Measure the oil clearance on each crankshaft bearing by means of plastigage. If the measurement is not within the specification, replace the defective bearing with an undersize one, and replace or recondition the crankshaft as necessary. Crankshaft oil clearance: Standard 0.010 - 0.030 mm (0.0004 - 0.0012 in) Limit 0.040 mm (0.0016 in)

Scheme 242

Scheme 243

1. Disconnect the ground cable from battery.
2. Remove the air intake chamber. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#intake-induction-h4so-engine), Air Intake Chamber. >
3. Remove the engine harness connector from bracket. (Scheme 221): Identifying Engine Harness Connector
4. Disconnect the connector from the oil switching solenoid valve.
5. Remove the oil switching solenoid valve.
6. Remove the variable valve lift diagnosis oil pressure switch. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Variable Valve Lift Diagnosis Oil Pressure Switch. >
7. Remove the oil temperature sensor. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Oil Temperature Sensor. >
8. Remove the oil switching solenoid valve holder from cylinder head. (Scheme 222): Identifying Oil Switching Solenoid Valve Holder And Oil Temperature Sensor - RH Side

Scheme 244

1. Disconnect the ground cable from battery.
2. Remove the V-belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), V-belt. >
3. Remove the crank pulley. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Crank Pulley. >
4. Remove the timing belt cover. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt Cover. >
5. Remove the timing belt. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Timing Belt. >
6. Remove the cam sprocket. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/mechanical/#engine-mechanical-h4so), Cam Sprocket. >
7. Remove the timing belt cover No. 2 (LH).
8. Disconnect the connector from the oil switching solenoid valve.
9. Remove the oil switching solenoid valve.
10. Remove the variable valve lift diagnosis oil pressure switch. < Ref. to «REMOVAL»(/subaru/impreza-wrx/gdgg-2-2005-2007/remont/fuel-system/#fuel-injection-fuel-systems-h4so), Variable Valve Lift Diagnosis Oil Pressure Switch. >
11. Remove the oil switching solenoid valve holder from cylinder head. (Scheme 223): Identifying Oil Switching Solenoid Valve Holder And Oil Temperature Sensor - LH Side

RH SIDE

Install in the reverse order of removal.

Note. Apply liquid gasket to the thread of variable valve lift diagnosis oil pressure switch. Use a new gasket.

Liquid gasket

THREE BOND 1324 (Part No. 004403042)

Tightening torque

T1: 6.4 N.m (0.65 kgf-m, 4.7 ft-lb)

T2: 10 N.m (1.0 kgf-m, 7.4 ft-lb)

T3: 17 N.m (1.7 kgf-m, 12.5 ft-lb)

T4: 18 N.m (1.8 kgf-m, 13.3 ft-lb)

Scheme 245

LH SIDE

Install in the reverse order of removal.

Note. Apply liquid gasket to the thread of variable valve lift diagnosis oil pressure switch. Use a new gasket.

Liquid gasket

THREE BOND 1324 (Part No. 004403042)

Tightening torque

T1: 6.4 N.m (0.65 kgf-m, 4.7 ft-lb)

T2: 10 N.m (1.0 kgf-m, 7.4 ft-lb)

T3: 17 N.m (1.7 kgf-m, 12.5 ft-lb)

Scheme 246

For the removal and installation procedure of intake and exhaust valve, refer to "Cylinder Head". < Ref. to REMOVAL , Cylinder Head. > < Ref. to INSTALLATION , Cylinder Head. >

For the removal and installation procedure of piston, refer to "Cylinder Block". < Ref. to REMOVAL , Cylinder Block. > < Ref. to INSTALLATION , Cylinder Block. >

For the removal and installation procedure of connecting rod, refer to "Cylinder Block". < Ref. to REMOVAL , Cylinder Block. > < Ref. to INSTALLATION , Cylinder Block. >

For the removal and installation procedure of crankshaft, refer to "Cylinder Block". < Ref. to REMOVAL , Cylinder Block. > < Ref. to INSTALLATION , Cylinder Block. >

Note. "RANK" shown in the chart refers to the possibility of reason for the trouble in order ("Very often" to "Rarely")

SYMPTOM CHART

ENGINE NOISE POSSIBLE CAUSE

See also:
• RELEASING OF FUEL PRESSURE
• REMOVAL
• BASIC DIAGNOSTIC PROCEDURE
• REMOVAL
• REMOVAL
• REMOVAL
• RH SIDE
• LH SIDE
• PROCEDURE
• REMOVAL
• REMOVAL
• REMOVAL
• REMOVAL
• INSTALLATION
• INSTALLATION
• INSPECTION
• INSTALLATION
• SPECIAL TOOL
• ADJUSTMENT
• FRONT SIDE BELT
• REMOVAL
• INSPECTION
• VALVE SEAT