Dodge Ram Truck 1500-2500-3500. Manual — part 1336

CLEANING

1. Clean the exhaust manifold using a suitable cleaning solvent, then allow to air dry.

2. Clean all gasket residue from the manifold mating surface.

INSPECTION

1. Inspect the exhaust manifold for cracks in the mating surface and at every mounting bolt hole.

2. Using a straight edge and a feeler gauge, check the mating surface for warp and twist.

3. Inspect the manifold to exhaust pipe mating surface for cracks, gouges, or other damage that would prevent

sealing.

INSTALLATION

RIGHT EXHAUST MANIFOLD

1. Install exhaust manifold and gasket from below engine compartment.

2. Install lower exhaust manifold fasteners. DO NOT tighten until all fasteners are in place.

3. Lower vehicle and install upper exhaust manifold fasteners. Tighten all manifold bolts 91,2,3) starting at center

and working outward to 25 N·m (18 ft. lbs.).

CAUTION: Over tightening heat shield fasteners, may cause shield to distort and/or crack.

4. Install exhaust manifold heat shield. Tighten fasteners (4,5) to 8 N·m (72 in. lbs.), then loosen 45 degrees.

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5. Install starter and fasteners.

6. Connect exhaust pipe to manifold.

7. Connect heater hoses at engine.

8. Install fastener attaching A/C accumulator.

9. Install A/C compressor and fasteners.

10. Install accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - INSTALLATION).

11. Install air cleaner assembly, resonator assembly and air inlet hose.

12. Install battery and connect cables.

13. Fill cooling system (Refer to 7 - COOLING - STANDARD PROCEDURE).

LEFT EXHAUST MANIFOLD

1. Install exhaust manifold and gasket from below engine compartment.

2. Install lower exhaust manifold fasteners. DO NOT tighten until all fasteners are in place.

3. Lower vehicle and install upper exhaust manifold fasteners. Tighten all manifold bolts (2,3) starting at center and

working outward to 25 N·m (18 ft. lbs.).

CAUTION: Over tightening heat shield fasteners, may cause shield to distort and/or crack.

4. Install exhaust manifold heat shield. Tighten fasteners (4,5) to 8 N·m (72 in. lbs.), then loosen 45 degrees.

5. Connect exhaust pipe to manifold.

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6. Connect negative cable to battery.

VALVE TIMING

DESCRIPTION - TIMING DRIVE SYSTEM

The timing drive system has been designed to provide quiet performance and reliability to support a non-free
wheeling engine. Specifically the intake valves are non-free wheeling and can be easily damaged with forceful
engine rotation if camshaft-to-crankshaft timing is incorrect. The timing drive system consists of a primary chain and
two secondary timing chain drives.

OPERATION - TIMING DRIVE SYSTEM

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 thirty 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 lubri-
cation for the two bushings used in the idler sprocket assembly.

There are two secondary drive chains, both are inverted tooth type, one to drive the camshaft in each SOHC cyl-
inder head. There are no shaft speed changes in the secondary chain drive system. Each secondary chain drives
a thirty tooth cam sprocket directly from the thirty 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

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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 clog-
ging by a fine mesh screen which is located on the back of the hydraulic tensioners.

STANDARD PROCEDURE

STANDARD PROCEDURE - MEASURING TIMING CHAIN WEAR

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

1. Remove the timing chain cover. (Refer to 9 -

ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).

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
15mm (0.5906 inches).

3. If the measurement exceeds the specification the

secondary timing chains are worn and require
replacement. (Refer to 9 - ENGINE/VALVE TIM-
ING/TIMING BELT/CHAIN AND SPROCKETS -
REMOVAL).

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

STANDARD PROCEDURE - ENGINE TIMING - VERIFICATION

CAUTION: The 4.7L is a non free-wheeling design engine. Therefore, correct engine timing is critical.

NOTE: Components referred to as left hand or right hand are as viewed from the drivers position inside the
vehicle.

NOTE: The blue link plates on the chains and the dots on the camshaft drive sprockets may not line up
during the timing verification procedure. The blue link plates are lined up with the sprocket dots only when
re-timing the complete timing drive. Once the timing drive is rotated blue link-to-dot alignment is no longer
valid.

Engine base timing can be verified by the following procedure:

1. Remove the cylinder head covers (Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) -

REMOVAL).

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