2.0L 4-Cylinder: Other Mazda 626 GF

Checking Valve Clearance

1. Remove valve cover. Ensure engine is cold. Turn crankshaft clockwise to position No. 1 piston at TDC of compression stroke. Measure and record clearance between camshaft lobe and adjustment shim at specified valves. See «VALVE ADJUSTMENT SEQUENCE»(ref-3925-S32908975632000052600000) table.
2. To measure clearance on remaining valves, rotate crankshaft clockwise 360 degrees (one full turn) until No. 4 piston is at TDC of compression stroke. Measure and record clearance at specified valves. See «VALVE ADJUSTMENT SEQUENCE»(ref-3925-S32908975632000052600000) table. Clearance should be .0089-.0116" (.225-.295 mm) for all valves. If clearance is not as specified, replace adjustment shim. See «ADJUSTING VALVE CLEARANCE»(ref-3925-S29624305702000052600000) .

VALVE ADJUSTMENT SEQUENCE

Adjusting Valve Clearance

1. Turn crankshaft clockwise so that camshaft lobe on valve requiring clearance adjustment is positioned straight up, away from valve. Remove appropriate camshaft cap bolts as necessary. (Scheme 20) See «CAMSHAFT BOLT REMOVAL»(ref-3925-S40776859242000052600000) table. NOTE: For No. 2 and 3 cylinder exhaust valve adjustment shim removal, remove bolt "A" or "C". For No. 2 and 3 cylinder intake valve adjustment shim removal, remove bolt "B" or "D". CAMSHAFT BOLT REMOVAL Remove Bolt (1) Adjust Clearance On Cylinder No. (Valves) A 1, 2 & 3 (Exhaust) B 1, 2 & 3 (Intake) C 2, 3 & 4 (Exhaust) D 2, 3 & 4 (Intake) (1) se Illustration for bolt locations. (Scheme 20)
2. Assemble Adjustment Tool Shaft & Clamp (49-T012-002 and 49-T012-003), aligning marks on adjustment tools. (Scheme 21) Install shaft and clamp on appropriate camshaft using camshaft cap bolts. Tighten cap bolts to 100-125 INCH lbs. (11.3-14.1 N.m). (Scheme 22) Tighten clamp bolt to secure shaft.
3. Face Body (49-T012-001) toward center of cylinder head. Mount body on shaft at point of adjustment shim to be replaced. (Scheme 22) Face notch of tappet so that thin-bladed screwdriver can be inserted. (Scheme 23) Set body on tappet by its notch. Tighten short bolt to secure body to shaft. CAUTION: Use caution when depressing tappet. Cylinder head can be damaged by body tip when tappet is depressed.
4. Tighten long bolt on body to depress tappet. Using thin-blade screwdriver, pry up on adjustment shim through notch on tappet. Using a magnet, remove shim and measure shim thickness. Select proper adjustment shim to obtain clearance of.009-.012" (.23-.30 mm). Push selected shim into tappet. Loosen long bolt to allow tappet to move up. Loosen short bolt and remove body. Remove shaft and clamp. Install camshaft cap bolts. See «TORQUE SPECIFICATIONS»(ref-3925-S00350375562000052600000). Recheck valve clearance.

Scheme 20

Scheme 21

Scheme 22

Scheme 23

Releasing Pressure

Locate and remove fuel pump relay from fuse/relay block on left front inner fender, in engine compartment. (Scheme 24) Start engine and allow to stall. After engine stalls, attempt to restart engine to ensure no residual pressure exists. Turn ignition off and reinstall fuel pump relay. When disconnecting fuel hoses, cover connection with shop rag to catch fuel leakage. To avoid excessive cranking after servicing or to pressurize fuel system to check for fuel leaks, prime fuel system before starting engine.

Priming System

Ensure fuel system is closed. Remove fuel pump relay from fuse/relay block. (Scheme 24) Connect a jumper wire between fuel pump relay terminal No. 30 and ground. (Scheme 25) Fuel pump will run as long as jumper wire is connected. After about 10 seconds, remove jumper wire from fuel pump relay socket.

Scheme 24

Scheme 25

COOLING SYSTEM BLEEDING

1. Slowly pour coolant into radiator at a rate of 1.1 qt. (1.0L) per minute maximum until coolant is level with filler port. Fill coolant reservoir to "F" mark. Securely install radiator cap. Start engine.
2. Operate engine at idle until normal operating temperature is reached. If coolant level warning light illuminates during warm-up, turn engine off and check drain plug and coolant hoses for leaks. Operate engine at 2200-2800 RPM for 5 minutes. Stop engine and allow to cool.
3. Repeat steps 1 and 2 . Check coolant level. If engine coolant is not level with filler neck, repeat entire procedure. If engine coolant is level with filler neck, fill reservoir to "F" mark.

ENGINE

Note. Remove engine and transaxle as an assembly from above.

CYLINDER HEAD

FRONT COVER

Note. Front cover contains oil pump. For removal and installation procedures, see OIL PUMP & FRONT COVER under ENGINE OILING.

TIMING BELT

Note. For timing belt removal and installation, see TIMING BELT REPLACEMENT - 2.0L - EXCEPT TRIBUTE article.

RADIATOR

Note. Numbers in parenthesis refer to numbers in illustration.

OIL PAN

Note. If removing oil pan to access crankshaft or other components at bottom of cylinder block, oil pan upper block must also be removed. See OIL PAN UPPER BLOCK. see scheme 19

Clean carbon and gasket material from all mating surfaces. Using a tap, clean cylinder head threads. Check cylinder head warpage. If warpage exceeds specification, resurface head, but DO NOT exceed grinding limit. See CYLINDER HEAD table under ENGINE SPECIFICATIONS. After resurfacing cylinder head, check cylinder head height. Replace cylinder head if height is less than minimum specification.

Valve Springs

Ensure valve spring free length, out-of-square and compressed length are within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS. Replace valve springs if necessary.

Note. Intake and exhaust valve stem seals are different. Exhaust seals can be identified by ridges molded into top of seal. Intake seals do not have identifying ridges. Incorrect installation of valve stem seals will cause premature failure.

Valve Stem Oil Seals

Exhaust valve stem oil seal has ridges on top. Use Installer Set (49-L012-0A0) to install valve seals. (Scheme 26) Adjust installer dimension "L" to seal depth of.697-.720" (17.7-18.3 mm). Using only hand pressure, install seal until it contacts cylinder head. Lightly oil valve seal lip.

Scheme 26

Valve Guides

1. Intake and exhaust valve guides are the same. Check valve stem-to-valve guide oil clearance. Ensure valve guide inside diameter is within specification. See «CYLINDER HEAD»(ref-3925-S19200592872000052600000) table under ENGINE SPECIFICATIONS.
2. Using Valve Guide Remover (49-B012-005), drive valve guide out, working from combustion chamber side of cylinder head. If required, install new circlip on guide. Using proper components of Valve Guide Installer (49-L012-002), adjust installer guide depth (dimension "L") to specification using depth micrometer or caliper. See «VALVE GUIDE INSTALLED HEIGHT»(ref-3925-S29346129432000052600000) table. (Scheme 27)
3. Insert guide into pre-adjusted installer, and drive guide into cylinder head from camshaft side until guide circlip, and/or installer contact cylinder head. Measure dimension "L" (guide installed height). (Scheme 27)or (Scheme 28). If installed height is not within specification, adjust or replace valve guide or cylinder head as necessary. See «VALVE GUIDE INSTALLED HEIGHT»(ref-3925-S29346129432000052600000) table.

VALVE GUIDE INSTALLED HEIGHT

Scheme 27

Scheme 28

Valve Seat

1. Service valve guide before valve seat. Valve seat replacement information is not available from manufacturer. Inspect valve seat for roughness and damage. Check valve seat angle and seat width.
2. Measure seat contact width on valve and ensure seat contact position is in center of valve face. Service seat if angle and width are not within specification. See «CYLINDER HEAD»(ref-3925-S19200592872000052600000) table under ENGINE SPECIFICATIONS. Measure valve installed height after servicing valve seat. (Scheme 28) See «VALVE INSTALLED HEIGHT»(ref-3925-S10701628792000052600000) table.
3. If valve installed height is within normal service range, proceed with repair. If installed height exceeds normal range, replace cylinder head.

VALVE INSTALLED HEIGHT

Valves

Check valve face angle, head diameter, margin thickness and stem diameter. Service or replace valves if measurements are not within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS.

Valve Seat Correction Angles

Measure seat contact width on valve. See VALVE SEAT . If seat width is not within specification, or if valve face does not contact center of valve seat, correct seat using grinding stone of specified angle. See VALVE SEAT CORRECTION ANGLES table. After correcting seat, lightly finish seat with 45-degree grinding stone.

VALVE SEAT CORRECTION ANGLES

Fitting Pistons

1. Ensure pistons are not scored or damaged. Measure piston diameter on piston skirt at 90-degree angle from piston pin, .65" (16.5 mm) below lowest ring groove. See «PISTONS, PINS & RINGS»(ref-3925-S40324146772000052600000) table under ENGINE SPECIFICATIONS.
2. Check piston-to-cylinder wall clearance in 3 different vertical places of piston travel. If clearance is not within specification, re-bore cylinders to fit oversize pistons. Using NEW piston rings, measure piston ring side clearance around entire piston circumference. If clearance is not within specification, replace piston. See «PISTONS, PINS & RINGS»(ref-3925-S40324146772000052600000) table under ENGINE SPECIFICATIONS.

Note. Pistons and rings are available in .010" (.25 mm) and .020" (.50 mm) oversize.

Piston Rings

1. If ring end gap and side clearance are not within specification, replace piston and/or rings as necessary. See «PISTONS, PINS & RINGS»(ref-3925-S40324146772000052600000) table under ENGINE SPECIFICATIONS.
2. Install oil ring spacer. Ensure ends do not overlap. (Scheme 29) Upper and lower rails are the same and are interchangeable. Install rails, ensuring rails are expanded by spacer tangs (oil rings when assembled should rotate freely). Install rings No. 2 (second) with scraper face downward. Install No. 1 (top) with chamfer toward top of piston. Ensure ring end gaps are properly positioned around piston. (Scheme 30)

Scheme 29

Scheme 30

Crankshaft & Main Bearings

1. Check crankshaft connecting rod journals for wear, out-of-round, taper and undersize. Machine or replace crankshaft and/or bearings as necessary. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-3925-S02779268342000052600000) table under ENGINE SPECIFICATIONS.
2. Before removing main cap, measure and record crankshaft end play by prying crankshaft forward, then rearward. Using Plastigage, measure and record main bearing oil clearance. Remove crankshaft. Measure and record each main and connecting rod journal diameter in 2 directions. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-3925-S02779268342000052600000) table under ENGINE SPECIFICATIONS.
3. Install main bearing caps with square mark facing front of engine. Tighten main bearing cap bolt in 2-3 steps, working outward from center bearing. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(ref-3925-S00350375562000052600000) .

Thrust Bearing

Install thrust bearing before installing crankshaft. Check crankshaft end play with crankshaft bearings and caps installed, but without connecting rods attached to crankshaft. DO NOT turn crankshaft until bearings are lubricated. If crankshaft end play exceeds specification, grind crankshaft and replace thrust bearings with oversize thrust bearings, or replace crankshaft and thrust bearings. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.

Cylinder Block

1. Check head gasket surface for warpage. If warpage is not within specification, machine or replace cylinder block as necessary. See «CYLINDER BLOCK»(ref-3925-S11294346872000052600000) table under ENGINE SPECIFICATIONS. Remove, clean and install oil jets for piston oil spraying.
2. Measure cylinder bore diameter just below top of bore, at middle of cylinder bore and just above bottom of cylinder bore. Ensure cylinder bore diameter, taper, out-of-round and piston-to-cylinder bore clearance are within specification. If cylinder bore diameter, taper, out-of-round or piston-to-cylinder bore clearance exceeds specification, bore cylinder to nearest oversize. Cylinder block can be bored for .010" (.25 mm) or .020" (.50 mm) oversize pistons.

Oil Pressure

With engine at operating temperature, oil pressure should be 57-71 psi (4-5 kg/cm 2 ) at 3000 RPM.

Oil Pressure Relief Valve

Pressure relief valve opening pressure is 64-78 psi (4.5-5.5 kg/cm 2 ). Pressure relief valve is located in oil pump body and is not adjustable.