4.7L Engine - Service Information: Overview RAM Pickup 2500

DESCRIPTION

The camshafts consist of powdered metal steel lobes which are sinter-bonded to a steel tube. A steel post or nose piece is friction-welded to the steel camshaft tube. Five bearing journals are machined into the camshaft, four on the steel tube and one on the steel nose piece. Camshaft end play is controlled by two thrust walls that border the nose piece journal. Engine oil enters the hollow camshafts at the third journal and lubricates every intake lobe rocker through a drilled passage in the intake lobe.

Scheme 159

1. Remove the cylinder head cover. Refer to «COVER(S), Cylinder Head , Removal , 4.7L»(ref-457796-S21006565632012030200000) .
2. Mount Dial Indicator Set (special tool #C-3339A, Set, Dial Indicator) (1) to a stationary point at the front of the engine.
3. Position the dial indicator tip against the camshaft (2).
4. Push the camshaft toward rear of engine and adjust the dial indicator to zero.
5. Move the camshaft forward and note reading.
6. Camshaft end play must be within specification, if end play is not within specification replace defective part as necessary. Refer to «Specifications»(ref-457796-S29075114712012030200000) .

Scheme 160

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Scheme 166

1. Remove the cylinder head cover(s) (1). Refer to «COVER(S), Cylinder Head , Removal , 4.7L»(ref-457796-S21006565632012030200000) . CAUTION: When the timing chain is removed and the cylinder heads are still installed, Do not forcefully rotate the camshafts or crankshaft independently of each other. Severe valve and/or piston damage can occur.
2. Set #1 cylinder to TDC and align the camshaft sprocket V8 mark (1) to the 12 o'clock position.
3. Mark the link on the secondary timing chain that is aligned with the two dots (2) on the camshaft sprocket as shown in illustration to aid in installation. CAUTION: Do not hold or pry on the camshaft target wheel for any reason, severe damage will occur to the target wheel resulting in a vehicle no start condition. CAUTION: When removing the camshaft sprocket, timing chains or camshaft, the timing chain tensioner must be secured, failure to use Locking Wedge (special tool #9867, Wedge, Locking) will result in hydraulic tensioner ratchet over extension, requiring timing chain cover removal to reset the tensioner ratchet. CAUTION: Do not force Locking Wedge (special tool #9867, Wedge, Locking) past the narrowest point between the chain strands. Damage to the tensioners may occur.
4. Position Locking Wedge (special tool #9867, Wedge, Locking) (2) between the timing chain strands (1), gently tap the wedge into position and secure the timing chain against the tensioner arm and guide.
5. Using Spanner Wrench (special tool #6958, Wrench, Spanner) (2) with Adapter Pins (special tool #8346, Pins, Adapter), secure the camshaft sprocket (3) and remove the camshaft sprocket bolt.
6. Disconnect the electrical connector to the Camshaft Position Sensor (CMP).
7. Remove the CMP sensor retaining bolt
8. Using a slight rocking motion, carefully remove the CMP sensor (1).
9. Check the condition of the CMP sensor O-ring, replace as necessary.
10. Position Camshaft Holder (special tool #8428A, Holder, Camshaft) (1) onto the camshaft (3).
11. Using Camshaft Holder (special tool #8428A, Holder, Camshaft) (1), hold the camshaft while removing the camshaft sprocket (2).
12. Using Camshaft Holder (special tool #8428A, Holder, Camshaft) (1), gently allow the camshaft to rotate 45° counterclockwise until the camshaft is in the neutral position (no valve load). CAUTION: Do not stamp or strike the camshaft bearing caps or severe engine damage may result. NOTE: When the camshaft is removed the rocker arms may slide downward, mark the rocker arms before removing camshaft.
13. Using the sequence shown in illustration, loosen the camshaft bearing cap retaining bolts 1/2 turn at a time until all load is off the bearing caps and remove bolts.
14. Remove the camshaft bearing caps and the camshaft.

Scheme 167

Scheme 168

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Scheme 170

Scheme 171

1. Remove the cylinder head cover. Refer to «COVER(S), Cylinder Head , Removal , 4.7L»(ref-457796-S21006565632012030200000) . CAUTION: When the timing chain is removed and the cylinder heads are still installed, Do not forcefully rotate the camshafts or crankshaft independently of each other. Severe valve and/or piston damage can occur.
2. Set #1 cylinder to TDC and align the camshaft sprocket V8 mark (1) to the 12 o'clock position.
3. Mark the link on the secondary timing chain that is aligned with the two dots (2) on the camshaft sprocket as shown in illustration to aid in installation. CAUTION: When removing the camshaft sprocket, timing chains or camshaft, the timing chain tensioner must be secured, failure to use Locking Wedge (special tool #9867, Wedge, Locking) will result in hydraulic tensioner ratchet over extension, requiring timing chain cover removal to reset the tensioner ratchet. CAUTION: Do not force Locking Wedge (special tool #9867, Wedge, Locking) past the narrowest point between the chain strands. Damage to the tensioners may occur.
4. Position Locking Wedge (special tool #9867, Wedge, Locking) (1) between the timing chain strands (2), gently tap the wedge into position and secure the timing chain against the tensioner arm and guide.
5. Using Spanner Wrench (special tool #6958, Wrench, Spanner) (4) with Adapter Pins (special tool #8346, Pins, Adapter), secure the camshaft sprocket (2) and remove the camshaft sprocket bolt.
6. Position Camshaft Holder (special tool #8428A, Holder, Camshaft) (1) onto the camshaft (2).
7. Using Camshaft Holder (special tool #8428A, Holder, Camshaft) (1), hold the camshaft while removing the camshaft sprocket (3).
8. Using Camshaft Holder (special tool #8428A, Holder, Camshaft) (1), gently allow the camshaft to rotate 15° clockwise until the camshaft is in the neutral position (no valve load). CAUTION: Do not stamp or strike the camshaft bearing caps or severe engine damage may result. NOTE: When the camshaft is removed the rocker arms may slide downward, mark the rocker arms before removing camshaft.
9. Using the sequence shown in illustration, loosen the camshaft bearing cap retaining bolts 1/2 turn at a time until all load is off the bearing caps and remove bolts.
10. Remove the camshaft bearing caps and the camshaft.

Scheme 172

Scheme 173

1. Lubricate the camshaft journals with clean engine oil. NOTE: Position the right side camshaft so that the camshaft sprocket dowel is near the 10 o'clock position, this will place the camshaft at the neutral position easing the installation of the camshaft bearing caps.
2. Install the camshaft into the cylinder head while aligning the camshaft sprocket dowel near the 10 o'clock position. NOTE: The camshaft caps are marked for location. The arrow must point to the front of the engine.
3. Install the camshaft bearing caps in the same position as noted during removal.
4. Install the camshaft bearing cap retaining bolts hand tight.
5. Using the sequence shown in illustration, working in 1/2 turn increments, tighten the bearing cap retaining bolts to 11 N.m (8 ft. lbs.).
6. Check the camshaft end play. Refer to «CAMSHAFT, Engine , Standard Procedure , 4.7L»(ref-457796-S05841556012012030200000) .
7. Position the camshaft drive gear into the timing chain while aligning the two dots on the camshaft sprocket with the chain link (2) marked during removal.
8. Using Camshaft Holder (special tool #8428A, Holder, Camshaft) (1), rotate the camshaft until the camshaft sprocket dowel is aligned with the slot in the camshaft sprocket.
9. Position the sprocket onto the camshaft. CAUTION: Remove excess oil from the camshaft sprocket retaining bolt, failure to do so can cause bolt over-torque resulting in bolt failure.
10. Remove excess oil from the camshaft sprocket retaining bolt.
11. Install the camshaft sprocket retaining bolt hand tight.
12. Remove the timing chain (1) Locking Wedge (special tool #9867, Wedge, Locking) (2).
13. Using Spanner Wrench (special tool #6958, Wrench, Spanner) (2) with Adapter Pins (special tool #8346, Pins, Adapter), secure the camshaft sprocket (3) and tighten the retaining bolt (1) to 122 N.m (90 ft. lbs.).
14. Install the cylinder head cover (1). Refer to «COVER(S), Cylinder Head , Installation , 4.7L»(ref-457796-S35079994162012030200000) . NOTE: Before installing the CMP sensor into the cylinder head, the machined hole must be clean of any dirt or debris.
15. Clean machined hole in the cylinder head (1).
16. Apply a small amount of engine oil to CMP sensor O-ring.
17. Install the CMP sensor (2) into the cylinder head with a slight rocking motion. Do not twist sensor into position as damage to O-ring may result. CAUTION: Before tightening sensor mounting bolt, be sure sensor is completely flush to cylinder head. If sensor is not flush, damage to sensor mounting tang may result.
18. Install the retaining bolt (3) and tighten to 12 N.m (9 ft. lbs.).
19. Connect the electrical connector (4) to the CMP sensor.

The cylinder head covers are made of injection molded thermo-set plastic, and are not interchangeable from side-to-side. It is imperative that nothing rest on the cylinder head covers. Prolonged contact with other items may wear a hole in the cylinder head cover.

Scheme 174

1. Disconnect battery negative cable.
2. Remove air cleaner assembly, resonator assembly and air inlet hose.
3. Drain cooling system. Refer to «Standard Procedure»(ref-457792-S30781673372012030200000) .
4. Remove accessory drive belt. Refer to «BELT, Serpentine , Removal»(ref-457792-S18686393612012030200000) .
5. Remove air conditioning compressor retaining bolts and move compressor to the left.
6. Remove heater hoses.
7. Disconnect and remove positive crankcase ventilation (PCV) hose.
8. Remove oil fill tube.
9. Remove spark plug wires (3).
10. Remove right rear breather tube and filter assembly.
11. Remove cylinder head cover retaining bolts.
12. Remove cylinder head cover.

Note. The gasket may be used again, provided no cuts, tears, or deformation has occurred.

Scheme 175

1. Disconnect negative cable from battery.
2. Remove the resonator assemble and air inlet hose.
3. Remove the spark plug wires (3).
4. Route injector harness in front of cylinder head cover.
5. Disconnect the left side breather tube and remove the breather tube.
6. Remove the cylinder head cover mounting bolts.
7. Remove cylinder head cover and gasket.

Note. The gasket may be used again, provided no cuts, tears, or deformation has occurred.

The rocker arms are steel stampings with an integral roller bearing. The rocker arms incorporate an 0.5 mm (0.019 inch) oil hole in the ball socket for roller and camshaft lubrication.

The valve stem 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 valve springs are made from high strength chrome silicon steel. The springs are common for intake and exhaust applications. The valve spring seat is integral with the valve stem seal, which is a positive type seal to control lubrication.

The valves are made of heat resistant steel and have chrome plated stems to prevent scuffing. Each valve is actuated by a roller rocker arm which pivots on a stationary lash adjuster. All valves use three bead lock keepers to retain the springs and promote valve rotation.

The cylinder block is made of cast iron. The block is a closed deck design with the left bank forward. To provide high rigidity and improved NVH an enhanced compacted graphite bedplate is bolted to the block. The block design allows coolant flow between the cylinders bores, and an internal coolant bypass to a single poppet inlet thermostat is included in the cast aluminum front cover.

Scheme 176

Before honing, stuff plenty of clean shop towels under the bores and over the crankshaft to keep abrasive materials from entering the crankshaft area.

1. Used carefully, the Cylinder Bore Sizing Hone (special tool #C-823, Hone, Cylinder), equipped with 220 grit stones, is the best tool for this job. In addition to deglazing, it will reduce taper and out-of-round, as well as removing light scuffing, scoring and scratches. Usually, a few strokes will clean up a bore and maintain the required limits. CAUTION: DO NOT use rigid type hones to remove cylinder wall glaze.
2. Deglazing of the cylinder walls may be done if the cylinder bore is straight and round. Use a cylinder surfacing hone, Honing Tool (special tool #C-3501, Hone W/Oil, AMMCO Cylinder), equipped with 280 grit stones ((special tool #C-3501-3810, Stones, 220 Grit Honing)). about 20-60 strokes, depending on the bore condition, will be sufficient to provide a satisfactory surface. Using honing oil (special tool #C-3501-3880, Oil, Honing), or a light honing oil, available from major oil distributors. CAUTION: DO NOT use engine or transmission oil, mineral spirits, or kerosene.
3. Honing should be done by moving the hone up and down fast enough to get a crosshatch pattern (1). The hone marks should INTERSECT at 50° to 60° for proper seating of rings (2).
4. A controlled hone motor speed between 200 and 300 RPM is necessary to obtain the proper crosshatch angle. The number of up and down strokes per minute can be regulated to get the desired 50° to 60° angle. Faster up and down strokes increase the crosshatch angle.
5. After honing, it is necessary that the block be cleaned to remove all traces of abrasive. Use a brush to wash parts with a solution of hot water and detergent. Dry parts thoroughly. Use a clean, white, lint-free cloth to check that the bore is clean. Oil the bores after cleaning to prevent rusting.

The structural dust cover is made of die cast aluminum and joins the lower half of the transmission bell housing to the engine bedplate.

OPERATION

The structural cover provides additional powertrain stiffness and reduces noise and vibration.

The crankshaft is constructed of nodular cast iron. The crankshaft is a crosshaped four throw design with eight counterweights for balancing purposes. The crankshaft is supported by five select fit main bearings with the number three serving as the thrust washer location. The main journals of the crankshaft are cross drilled to improve rod bearing lubrication. The number eight counterweight has provisions for crankshaft position sensor target wheel mounting. The select fit main bearing markings are located on the rear side of the target wheel. The crankshaft oil seals are one piece design. The front oil seal is retained in the timing chain cover, and the rear seal is pressed in to a bore formed by the cylinder block and the bedplate assembly.

The pistons are made of a high strength aluminum alloy. The anodized top ring groove and crown has been replaced with a coated top ring that is blue in color on the bottom surface. Piston skirts are coated with a solid lubricant (Molykote) to reduce friction and provide scuff resistance. The connecting rods are made of forged powdered metal, with a "fractured cap" design. A pressed fit piston pin is used to attach the piston and connecting rod.

Scheme 177

Scheme 178

1. To correctly select the proper size piston, a cylinder bore gauge (2), capable of reading in 0.003 mm (.0001 in.) INCREMENTS is required. If a bore gauge is not available, do not use an inside micrometer. see scheme 136
2. Measure the inside diameter of the cylinder bore (3) at a point 38.0 mm (1.5 inches) below top of bore. Start perpendicular (across or at 90 degrees) to the axis of the crankshaft at point A and then take an additional bore reading 90 degrees to that at point B. 1 - MOLY COATED 2 - MOLY COATED
3. The coated pistons (1, 2) will be serviced with the piston pin and connecting rod pre-assembled. see scheme 137
4. The coating material is applied to the piston after the final piston machining process. Measuring the outside diameter of a coated piston (1,2) will not provide accurate results. Therefore measuring the inside diameter of the cylinder bore with a dial Bore Gauge is MANDATORY. To correctly select the proper size piston, a cylinder bore gauge capable of reading in 0.003 mm (.0001 in.) increments is required.
5. Piston installation into the cylinder bore requires slightly more pressure than that required for non-coated pistons. The bonded coating on the piston will give the appearance of a line-to-line fit with the cylinder bore.

Scheme 179

1. Disconnect negative cable from battery.
2. Remove the following components: Oil pan and gasket/windage tray. Refer to «PAN, Oil, Removal, 4.7L»(ref-457796-S06968229502012030200000). Cylinder head covers. Refer to «COVER(S), Cylinder Head, Removal, 4.7L»(ref-457796-S21006565632012030200000). Timing chain cover. Refer to «COVER(S), Engine Timing, Removal, 4.7L»(ref-457796-S27348107972012030200000). Cylinder head(s). Refer to «Cylinder Head, Removal, 4.7L»(ref-457796-S08821695472012030200000).
3. If necessary, remove top ridge of cylinder bores with a reliable ridge reamer before removing pistons from cylinder block. Be sure to keep tops of pistons covered during this operation. Pistons and connecting rods must be removed from top of cylinder block. When removing piston and connecting rod assemblies from the engine, rotate crankshaft so the each connecting rod is centered in cylinder bore. 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 removing to ensure correct reassembly.
4. Mark connecting rod and bearing cap positions using a permanent ink marker or scribe tool. see scheme 138 CAUTION: Care must be taken not to damage the fractured rod and cap joint face surfaces, as engine damage may occur.
5. Remove connecting rod cap. Install Special Tool (special tool #8507, Guides, Connecting Rod) Connecting Rod Guides into the connecting rod being removed. Remove piston from cylinder bore. Repeat this procedure for each piston being removed. CAUTION: Care must be taken not to nick crankshaft journals, as engine damage may occur.
6. Immediately after piston and connecting rod removal, install bearing cap on the mating connecting rod to prevent damage to the fractured cap and rod surfaces.
7. Carefully remove piston rings from piston(s), starting from the top ring down.

Oil from the oil pan is pumped by a gerotor type oil pump directly mounted to the crankshaft nose. Oil pressure is controlled by a relief valve mounted inside the oil pump housing.

The camshaft exhaust valve lobes and rocker arms are lubricated through a small hole in the rocker arm; oil flows through the lash adjuster then through the rocker arm and onto the camshaft lobe. Due to the orientation of the rocker arm, the camshaft intake lobes are not lubed in the same manner as the exhaust lobes. The intake lobes are lubed through internal passages in the camshaft. Oil flows through a bore in the number 3 camshaft bearing bore, and as the camshaft turns, a hole in the camshaft aligns with the hole in the camshaft bore allowing engine oil to enter the camshaft tube. The oil then exits through 1.6mm (0.063 in.) holes drilled into the intake lobes, lubricating the lobes and the rocker arms.

ENGINE BLOCK LUBRICATION FLOW CHART : TABLE 1

CYLINDER HEADS LUBRICATION FLOW CHART: TABLE 2

Scheme 180

1. Remove oil pressure sending unit (2) and install gauge assembly (special tool #C-3292A, Gauge, Pressure). see scheme 153
2. Run engine until thermostat opens.
3. Oil Pressure: Curb Idle - 25 kPa (4 psi) minimum 3000 RPM - 170 - 758 kPa (25 - 110 psi)
4. If oil pressure is 0 at idle, shut off engine. Check for a clogged oil pick-up screen or a pressure relief valve stuck open.

The oil pressure switch is a pressure sensitive switch that is activated by the engine's oil pressure (in the main oil gallery). The switch is a two terminal device (one terminal is provided to the wiring harness and the other terminal is the switch's metal housing that screws into the engine block).

The oil pressure switch is normally "Closed". The switch changes from a "Closed" circuit to an "Open" circuit, on increasing pressure of 7 psig. The oil pressure switch changes from an "Open" circuit to a "Closed" circuit, on decreasing pressure, between 2 psig and 4 psig.

The exhaust manifolds are log style with a patented flow enhancing design to maximize performance. The exhaust manifolds are made of high silicon molybdenum cast iron. A perforated core graphite exhaust manifold gasket is used to improve sealing to the cylinder head. The exhaust manifolds are covered by a three layer laminated heat shield for thermal protection and noise reduction. The heat shields are fastened with a torque prevailing nut that is backed off slightly to allow for the thermal expansion of the exhaust manifold.

Scheme 181

1. Disconnect the negative battery cable.
2. Remove the air cleaner assembly. Refer to «BODY, Air Cleaner , Removal , 4.7L»(ref-457796-S06661718552012030200000) .
3. Remove the accessory drive belt. Refer to «BELT, Serpentine , Removal»(ref-457792-S18686393612012030200000) .
4. Remove the A/C compressor. Refer to «COMPRESSOR, A/C , Removal»(ref-457787-S14624345472012030200000) .
5. Remove A/C accumulator support bracket fastener.
6. Drain the coolant below heater hose level. Refer to «Standard Procedure»(ref-457792-S30781673372012030200000) .
7. Remove the heater hoses at the engine.
8. Remove the exhaust manifold heat shield retaining nuts (4, 5) and remove the heat shield.
9. Remove the upper exhaust manifold retaining bolts (1, 2, 3).
10. Raise and support the vehicle. CAUTION: When servicing or replacing exhaust system components, disconnect the oxygen sensor connector(s). Allowing the exhaust to hang by the oxygen sensor wires will damage the harness and/or sensor.
11. Saturate the exhaust pipe/catalytic converter assembly flanged nuts at the exhaust manifold with heat valve lubricant, allow 5 minutes for penetration.
12. Disconnect the exhaust pipe/catalytic converter at the exhaust manifold. Refer to «CONVERTER, Catalytic , Removal»(ref-457794-S07022787092012030200000) .
13. Remove the starter. Refer to «STARTER , Removal»(ref-457802-S39254669482012030200000) .
14. Remove the lower exhaust manifold retaining bolts (1, 2, 3). NOTE: The exhaust manifold is removed from below the engine compartment.
15. Remove the exhaust manifold and gasket.
16. Clean the mating surfaces.

Scheme 182

1. Disconnect the negative battery cable.
2. Remove the engine cover.
3. Remove the front two exhaust manifold heat shield retaining nuts (4).
4. Raise and support the vehicle. CAUTION: When servicing or replacing exhaust system components, disconnect the oxygen sensor connector(s). Allowing the exhaust to hang by the oxygen sensor wires will damage the harness and/or sensor.
5. Saturate the exhaust pipe/catalytic converter assembly flanged nuts at the exhaust manifold with heat valve lubricant, allow 5 minutes for penetration.
6. Disconnect the exhaust pipe at the exhaust manifold. Refer to «CONVERTER, Catalytic , Removal»(ref-457794-S07022787092012030200000) .
7. Remove the rear heat shield (5) retaining nuts and remove the heat shield.
8. Lower the vehicle.
9. Remove the upper exhaust manifold retaining bolts (1, 2, 3). NOTE: The exhaust manifold is removed from below the engine compartment.
10. Raise and support the vehicle.
11. Remove the lower exhaust manifold retaining bolts (1, 2, 3).
12. Remove the exhaust manifold and gasket.
13. Clean the mating surfaces.

The intake manifold is made of a composite material and features long runners which maximizes low end torque. The intake manifold uses single plane sealing which consist of eight individual press in place port gaskets to prevent leaks.

The primary timing chain is a single inverted tooth type. The primary chain drives the large fifty tooth idler sprocket directly from a 25 tooth crankshaft sprocket. Primary chain motion is controlled by a pivoting leaf spring tensioner arm and a fixed guide. The arm and the guide both use nylon plastic wear faces for low friction and long wear. The primary chain receives oil splash lubrication from the secondary chain drive and oil pump leakage. The idler sprocket assembly connects the primary and secondary chain drives. The idler sprocket assembly consists of two integral 26 tooth sprockets and a fifty tooth sprocket that is splined to the assembly. The spline joint is a non - serviceable press fit anti rattle type. The idler sprocket assembly spins on a stationary idler shaft. The idler shaft is press-fit into the cylinder block. A large washer on the idler shaft bolt and the rear flange of the idler shaft are used to control sprocket thrust movement. Pressurized oil is routed through the center of the idler shaft to provide lubrication for the two bushings used in the idler sprocket assembly.

There are two secondary drive chains, one to drive the camshaft in each SOHC cylinder head. There are no shaft speed changes in the secondary chain drive system. Each secondary chain drives a 26 tooth cam sprocket directly from the 26 tooth sprocket on the idler sprocket assembly. A fixed chain guide and a hydraulic oil damped tensioner are used to maintain tension in each secondary chain system. The hydraulic tensioners for the secondary chain systems are fed pressurized oil from oil reservoir pockets in the block. Each tensioner also has a mechanical ratchet system that limits chain slack if the tensioner piston bleeds down after engine shut down. The tensioner arms and guides also utilize nylon wear faces for low friction and long wear. The secondary timing chains receive lubrication from a small orifice in the tensioners. This orifice is protected from clogging by a fine mesh screen which is located on the back of the hydraulic tensioners.

Scheme 183

Note. This procedure must be performed with the timing chain cover removed.

1. Remove the timing chain cover. Refer to «COVER(S), Engine Timing , Removal , 4.7L»(ref-457796-S27348107972012030200000) .
2. To determine if the secondary timing chains are worn, rotate the engine clockwise until maximum tensioner piston (2) extension is obtained. Measure the distance between the secondary timing chain tensioner housing and the step ledge on the piston. The measurement at point (A) must be less than 15 mm (0.5906 inches).
3. If the measurement exceeds the specification the secondary timing chains are worn and require replacement. Refer to «CHAIN and SPROCKETS, Timing , Removal , 4.7L»(ref-457796-S16479639572012030200000) .

Note. If the secondary chains are to be replaced the primary chain must also be replaced.