5.7L Engine - Service Information: Overview RAM Pickup 2500

DESCRIPTION

The 5.7L engine (348 CID) eight-cylinder engine is a 90° V-Type lightweight, deep skirt cast iron block, aluminum heads, single cam, overhead valve engine with hydraulic roller tappets. The heads incorporate splayed valves with a hemispherical style combustion chamber and dual spark plugs. The cylinders are numbered from front to rear; 1, 3, 5, 7 on the left bank and 2, 4, 6, 8 on the right bank. The firing order is 1-8-4-3-6-5-7-2.

OPERATION

The cylinder head closes the combustion chamber allowing the pistons to compress the air fuel mixture to the correct ratio for ignition. The valves located in the cylinder head open and close to either allow clean air into the combustion chamber or to allow the exhaust gases out, depending on the stroke of the engine.

The valve guide seals are made of rubber and incorporate an integral steel valve spring seat. The integral garter spring maintains consistent lubrication control to the valve stems.

The Variable Cam Timing (VCT) assembly is actuated with engine oil pressure. The oil flow to the VCT assemblies are controlled by an Oil Control Valve (OCV). The OCV consist of a Pulse Width Modulated (PWM) solenoid and a spool valve. The PCM actuates the OCV to control oil flow through the spool valve into the VCT assemblies. The VCT assembly consists of a rotor, stator, and sprocket. The stator is connected to the timing chain through the sprocket. The rotor is connected to the camshaft. Oil flow in to the VCT assembly rotates the rotor with respect to the stator, thus rotating the exhaust camshaft with respect to the timing chain and intake camshaft. An infinitely variable cam timing position can be achieved within the limits of the hardware. The CMP monitors the position of the camshaft with respect to the crankshaft and provides feedback to the PCM.

Scheme 321

1. Remove the timing chain and sprockets. Refer to «CHAIN and SPROCKETS, Timing , Removal , 5.7L»(ref-457797-S24060447012012030200000) .
2. Remove the camshaft phaser bolt (1).
3. Remove camshaft phaser (2).

Scheme 322

1. Align the slot (2) in the phaser (1) with the dowel on the camshaft. CAUTION: Never attempt to disassemble the camshaft phaser, severe engine damage could result.
2. Position the phaser (2) in place and install phaser retaining bolt (1) and tighten to 122 N.m (90 ft. lbs.).
3. Install the timing chain and sprockets. Refer to «CHAIN and SPROCKETS, Timing , Installation , 5.7L»(ref-457797-S28990632222012030200000) .

Scheme 323

With the crankshaft removed from the cylinder block.

Clean the oil off the main bearing journal.

Determine the maximum diameter of the journal with a micrometer. Measure at two locations 90° apart at each end of the journal.

The maximum allowable taper is 0.008 mm (0.0004 inch.) and maximum out of round is 0.005 mm (0.0002 inch). Compare the measured diameter with the journal diameter specification (Main Bearing Fitting Chart). Select the inserts required to obtain the specified bearing-to-journal clearance.

Scheme 324

The main bearings are "select fit" to achieve proper oil clearances. For main bearing selection, the crankshaft counterweight has grade identification marks stamped into it. These marks are read from left to right. The left letter (1) refers to the number one main journal and the right letter (2) refers to the number 5 journal.

Note. Service main bearings are coded. These codes identify what size or grade of the bearing.

MAIN BEARING SELECTION CHART - 5.7L

Scheme 325

Wipe the inserts clean and inspect for abnormal wear patterns and for metal or other foreign material imbedded in the lining. Normal main bearing insert wear patterns are illustrated.

Note. If any crankshaft journals are scored, the crankshaft must be repaired or replaced.

Inspect the back of the inserts for fractures, scrapings or irregular wear patterns.

Inspect the upper insert locking tabs for damage.

Replace all damaged or worn bearing inserts.

Scheme 326

1. Perform the fuel system pressure release procedure. Refer to «STANDARD PROCEDURE»(ref-457834-S04226998202012030200000) .
2. Remove the engine from the vehicle. Refer to «Removal , 5.7L»(ref-457797-S13097779332012030200000) .
3. Remove the flexplate. Refer to «FLEXPLATE , Removal , 5.7L»(ref-457797-S33878622702012030200000) . CAUTION: Do not damage the rear surface of the camshaft or the core plug sealing surface, when removing the core plug.
4. Using a suitable sharp punch, punch a small hole in the camshaft core hole plug (1).
5. Insert a short sheet metal screw into the small hole in the camshaft core hole plug.
6. Using a suitable slide hammer puller, remove the rear camshaft core hole plug.

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1. Remove the battery negative cable.
2. Remove the air cleaner assembly. Refer to «BODY, Air Cleaner , Removal , 5.7L»(ref-457797-S42752377112012030200000) .
3. Drain coolant. Refer to «Standard Procedure»(ref-457792-S30781673372012030200000) .
4. Remove the accessory drive belt. Refer to «BELT, Serpentine , Removal»(ref-457792-S18686393612012030200000) .
5. Remove the left and right cylinder heads. Refer to «Cylinder Head , Removal , 5.7L»(ref-457797-S12195487782012030200000) .
6. Remove the radiator. Refer to «RADIATOR, Engine Cooling , Removal»(ref-457792-S21225288992012030200000) .
7. Remove the oil pan. Refer to «PAN, Oil , Removal , 5.7L»(ref-457797-S04954463982012030200000) .
8. Remove timing case cover. Refer to «COVER(S), Engine Timing , Removal , 5.7L»(ref-457797-S09931747462012030200000) . NOTE: Identify lifters to ensure installation in original location.
9. Remove the tappets (2) and retainer (1) assembly.
10. Remove the oil pick up tube (1).
11. Remove the oil pump retaining bolts (2) and remove the oil pump (1).
12. Remove timing chain (5). Refer to «CHAIN and SPROCKETS, Timing , Removal , 5.7L»(ref-457797-S24060447012012030200000) .
13. Remove camshaft thrust plate (1). NOTE: Slowly rotate the camshaft while pulling camshaft out.
14. Install a long bolt (2) into front of camshaft (1) to aid in removal of the camshaft. Remove camshaft, being careful not to damage cam bearings with the cam lobes.

The Multiple Displacement System (MDS) selectively deactivates cylinders 1, 4, 6 and 7 during steady speed, low acceleration and shallow grade climbing conditions to increase fuel economy.

The MDS can provide a 5 to 20% fuel economy benefit when operating in four-cylinder mode. Depending on driving habits and vehicle usage. For EPA rating purposes the fuel economy is 8 to 15% higher than if the engine was operating on eight-cylinders at all times.

The MDS deactivating lifter (1) can be distinguished from the non-MDS lifter (2) by the disconnecting pin (3) on the side of the MDS lifter.

MDS is integrated into the basic engine architecture requiring these additional components

1. Unique MDS camshaft
2. 8 deactivating roller lifters
3. 4 MDS control valve solenoids
4. MDS control valve solenoid wiring harness
5. Oil temperature sensor

The Multiple Displacement System (MDS) provides cylinder deactivation during steady speed, low acceleration and shallow grade climbing conditions to increase fuel economy. Both four and eight cylinder configurations have even firing intervals to provide smooth operation. The MDS selectively deactivates cylinders 1,4,6, and 7, to improve fuel economy. All deactivated cylinders have unique hydraulic lifters that collapse when deactivated to prevent the valves from opening. Engine oil pressure is used to activate and deactivate the valves. Oil is delivered through special oil passages drilled into the cylinder block. The MDS solenoid valves control the flow. When activated, pressurized oil pushes a latching pin on each MDS lifter which becomes a lost motion link. The base of the MDS lifter follows the camshaft while the top remains stationary. The MDS lifter is held in place against the pushrod by light spring pressure but unable to move because of the much higher force of the valve spring.

Note. It is critical to use the recommended oil viscosity in engines that use MDS.

Deactivation occurs during the compression stroke of each cylinder, after air and fuel enter the cylinder. Ignition occurs, but the combustion products remain trapped in the cylinder under high pressure, because the valves no longer open. No fuel/air enters or leaves during subsequent piston strokes, this high pressure gas is repeatedly compressed and expanded like an air spring.

The pistons are made of a high strength aluminum alloy. Piston skirts are coated with a solid lubricant (Molykote R) to reduce friction and provide scuff resistance. The piston top ring groove and land is anodized. The connecting rods are made of forged powdered metal, with a fractured cap design.

Scheme 334

1. To correctly select the proper size piston, use Cylinder Indicator (special tool #C-119, Cylinder Indicator) (2) to measure the inside diameter of the cylinder bore (3). A cylinder bore gauge capable of reading in 0.003 mm (0.0001 in.) Increments is required. If a bore gauge is not available, do not use an inside micrometer.
2. Measure the inside diameter of the cylinder bore at a point 38.0 mm (1.5 inches) below the top of bore (4). Start perpendicular (across or at 90°) to the axis of the crankshaft at point A (1) and then take an additional bore reading 90° at point B (1).
3. The coated pistons will be serviced with the piston pin and connecting rod pre-assembled. The piston-rod assembly is specific for the left cylinder bank (odd numbered) and the right cylinder bank (even numbered) and must not be interchanged.
4. Measure the piston diameter with a micrometer at points (1,2).

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1. Perform the fuel system pressure release procedure. Refer to «STANDARD PROCEDURE»(ref-457834-S04226998202012030200000) .
2. Disconnect and isolate the negative battery cable (3).
3. Remove the engine covers (1).
4. Loosen clamp and disconnect the air duct at throttle body.
5. Disconnect the intake air temperature sensor (4) electrical connector.
6. Remove the makeup air hose (1).
7. Remove the air cleaner housing retaining bolt (3) and remove the air cleaner housing (2).
8. Remove the cylinder head(s). Refer to «Cylinder Head , Removal , 5.7L»(ref-457797-S12195487782012030200000) .
9. Raise and support the vehicle.
10. Remove the engine mount nuts (1, 2).
11. Remove the steering gear mounting bolts (1) and position the steering gear (2) aside.
12. Remove the engine oil dipstick and tube from the oil pan.
13. Lower the vehicle. NOTE: Do not use air tools to install engine lift fixture.
14. Install the Engine Lift Fixture (special tool #8984B, Fixture, Engine Lifting) (1), Engine Lift Adapter (special tool #8984-UPD, Adapter, Engine Lift) (2) and the Engine Support Fixture (special tool #8534B, Fixture, Driveline Support) (3).
15. Raise the engine to provide clearance to remove the oil pan.
16. Raise and support the vehicle.
17. Remove the oil pan. Refer to «PAN, Oil , Removal , 5.7L»(ref-457797-S04954463982012030200000) .
18. Lower the vehicle.
19. Remove the timing chain cover. Refer to «COVER(S), Engine Timing , Removal , 5.7L»(ref-457797-S09931747462012030200000) .
20. If necessary, remove the ridge on top of the cylinder bores with a reliable ridge reamer before removing the pistons from the cylinder block. Be sure to keep the tops of the pistons covered during this operation. CAUTION: Do not use a number stamp or a punch to mark connecting rods or caps, as damage to connecting rods could occur. NOTE: Connecting rods and bearing caps are not interchangeable and should be marked before removal to ensure correct reassembly.
21. Raise and support the vehicle.
22. Mark the connecting rod and bearing cap positions using a permanent ink marker or scribe tool. CAUTION: Care must be taken not to damage the fractured rod and cap joint face surfaces, as engine damage may occur. CAUTION: Care must be taken not to nick crankshaft journals, as engine damage may occur. NOTE: Pistons and connecting rods assemblies must be removed from the top of cylinder block. When removing the piston and connecting rod assemblies from the engine, rotate the crankshaft so each connecting rod is centered in the cylinder bore.
23. Remove the connecting rod cap, install the Connecting Rod Guides (special tool #8507, Guides, Connecting Rod) (1) and carefully remove the piston from the cylinder bore, repeat this procedure for each piston being removed.
24. Immediately after removing the piston and connecting rod, install the bearing cap on the mating connecting rod to prevent damage to the fractured cap and rod surfaces.
25. Carefully remove the piston rings from the piston(s), starting from the top ring down.

The crankshaft rear oil seal is integral to the crankshaft rear oil seal retainer, for more information refer to the following

1. Diagnosis and Testing : Refer to «RETAINER, Crankshaft Rear Oil Seal , Diagnosis and Testing , 5.7L»(ref-457797-S40294270772012030200000) .
2. Removal : Refer to «RETAINER, Crankshaft Rear Oil Seal , Removal , 5.7L»(ref-457797-S32772113992012030200000) .
3. Installation : Refer to «RETAINER, Crankshaft Rear Oil Seal , Installation , 5.7L»(ref-457797-S21891879812012030200000) .

The Multi Displacement System selectively deactivates cylinders 1, 4, 6 and 7, to improve fuel economy. It has two modes of operation

1. 8 cylinders for acceleration and heavy loads.
2. 4 cylinders for cruising and city traffic.

The main components of the Multi Displacement System are

1. Unique MDS camshaft.
2. Deactivating roller tappets.
3. 4 control valves/solenoids.
4. control valve/solenoid wiring harness.
5. oil temp sensor.

Cylinder Deactivation

1. Trap an exhaust charge from a normal combustion event
2. Normal combustion event
3. Don't open the exhaust valve
4. Don't open the intake valve
5. Piston is an air spring
6. Cylinders deactivated in firing sequence

Cylinder Reactivation

1. Open the exhaust valve
2. Empty the cylinder
3. Open the intake valve
4. Normal combustion event
5. Cylinders reactivated in firing sequence

The 5.7L engine is equipped with Variable Cam Timing (VCT). This system uses an oil control valve to direct oil pressure into the camshaft phaser assembly. The camshaft phaser assembly advances and/or retards camshaft timing to improve engine performance, mid-range torque, idle quality, fuel economy, and reduce emissions. The oil control valve is located under the intake manifold.

The Variable Cam Timing (VCT) assembly is actuated with engine oil pressure. The oil flow to the VCT assembly is controlled by an Oil Control Valve (OCV). The OCV consists of a Pulse Width Modulated (PWM) solenoid and a spool valve. The PCM actuates the OCV to control oil flow through the spool valve into the VCT assembly. The VCT assembly consists of a rotor and a stator/sprocket. The stator/sprocket is connected to the timing chain. The rotor is connected to the camshaft. Oil flow into the VCT assembly rotates the rotor with respect to the stator, thus rotating the camshaft with respect to the stator/sprocket. This will rotate both the intake and exhaust lobes on the camshaft by the same amount. The intake and exhaust lobes can not be individually controlled with this VCT system. An infinitely variable valve timing position can be achieved within the limits of the hardware. The camshaft position sensor monitors the position of the camshaft with respect to the crankshaft and provides feedback to the PCM.

Scheme 342

1. Remove intake manifold. Refer to «MANIFOLD, Intake , Removal , 5.7L»(ref-457797-S09573092392012030200000) .
2. Disconnect oil control valve electrical connector (2).
3. Remove oil control valve fastener (1). NOTE: To remove the oil control valve, the engine must be at room temperature.
4. Rotate the oil control valve to break the seal. Pull the oil control valve out.

The oil pressure sensor uses the following three circuits

1. Signal circuit to the PCM
2. Sensor ground circuit from the PCM
3. 5 volt reference circuit from the PCM

The oil pressure sensor returns a voltage signal back to the PCM with reference to oil pressure. Ground for the sensor is supplied by the PCM.

The oil pressure sensor is located on the right side of the engine block. The sensor screws into the engines main oil gallery.

Scheme 343

Scheme 344

1. Disconnect and isolate the negative battery cable.
2. Disconnect the oil pressure sensor electrical connector (1).
3. Remove the oil pressure sensor (1).

The oil temperature sensor uses the following two circuits

1. Signal circuit to the PCM
2. Ground circuit from the PCM

The oil temperature sensor is a Negative Thermal Coefficient sensor. The resistance of the sensor changes as oil temperature changes. This results in different output voltages back to the PCM.

The oil temperature sensor is located on the right side of the engine block.

Scheme 345

Scheme 346

1. Disconnect and isolate the negative battery cable.
2. Disconnect the oil temperature sensor electrical connector (1).
3. Remove the oil temperature sensor (1).