Fig DODGE RAM 1500 1998 2.G Workshop Manual

EXHAUST MANIFOLD
DESCRIPTION
The exhaust manifolds are log style with a pat-
ented flow enhancing design to maximize perfor-
mance. 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.
REMOVAL
RIGHT EXHAUST MANIFOLD
(1) Disconnect negative cable for battery.
(2) Remove air cleaner assembly, resonator assem-
bly and air inlet hose.
(3) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(4) Remove A/C compressor (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - REMOVAL).
(5) Remove A/C accumulator support bracket fas-
tener.(6) Drain coolant below heater hose level (Refer to
7 - COOLING - STANDARD PROCEDURE).
(7) Remove heater hoses at engine.
(8) Remove fasteners attaching exhaust manifold
heat shield.
(9) Remove heat shield.
(10) Remove upper exhaust manifold attaching fas-
teners.
(11) Raise vehicle on hoist.
(12) Disconnect exhaust pipe from manifold.
(13) Remove fasteners attaching starter. Move
starter aside.
(14) Remove lower exhaust manifold attaching fas-
teners.
(15) Remove exhaust manifold and gasket (Fig.
110). Manifold is removed from below the engine
compartment.
DRENGINE - 4.7L 9 - 161

Fig. 110 Exhaust ManifoldÐRight
ITEM DESCRIPTION TORQUE ITEM DESCRIPTION TORQUE
1 Stud (Qty 2)
25 N´m (18 ft. lbs.)4 Nut (Qty 2) 8 N´m (72 in. lbs.),
then loosen 45
degrees 2 Bolt (Qty 4) 5 Nut (Qty 2)
3 Stud (Qty 2)
9 - 162 ENGINE - 4.7LDR
EXHAUST MANIFOLD (Continued)

LEFT EXHAUST MANIFOLD
(1) Disconnect negative cable for battery.
(2) Hoist vehicle.
(3) Disconnect exhaust pipe at manifold.
(4) Lower vehicle.
(5) Remove the front two exhaust heat shield
retaining fasteners. Raise vehicle and remove the
fasteners at rear of heat shield.
(6) Remove heat shield (Fig. 111).
(7) Lower vehicle and remove the upper exhaust
manifold retaining bolts (Fig. 111).
(8) Raise vehicle and remove the lower exhaust
manifold retaining bolts (Fig. 111).
(9) Remove exhaust manifold and gasket (Fig.
111). Manifold is removed from below the engine
compartment.
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.
Fig. 111 Exhaust ManifoldÐLeft
ITEM DESCRIPTION TORQUE ITEM DESCRIPTION TORQUE
1 Stud (Qty 2)
25 N´m (18 ft. lbs.)4 Nut (Qty 2) 8 N´m (72 in. lbs.),
then loosen 45
degrees 2 Bolt (Qty 4) 5 Nut (Qty 2)
3 Stud (Qty 2)
DRENGINE - 4.7L 9 - 163
EXHAUST MANIFOLD (Continued)

INSTALLATION
RIGHT EXHAUST MANIFOLD
(1) Install exhaust manifold and gasket (Fig. 112)
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 mani-
fold fasteners. Tighten all manifold bolts 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 fas-
teners to 8 N´m (72 in. lbs.), then loosen 45 degrees.
(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 assem-
bly and air inlet hose.
(12) Install battery and connect cables.
(13) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
Fig. 112 Exhaust ManifoldÐRight
ITEM DESCRIPTION TORQUE ITEM DESCRIPTION TORQUE
1 Stud (Qty 2)
25 N´m (18 ft. lbs.)4 Nut (Qty 2) 8 N´m (72 in. lbs.),
then loosen 45
degrees 2 Bolt (Qty 4) 5 Nut (Qty 2)
3 Stud (Qty 2)
9 - 164 ENGINE - 4.7LDR
EXHAUST MANIFOLD (Continued)

LEFT EXHAUST MANIFOLD
(1) Install exhaust manifold and gasket from below
engine compartment.
(2) Install lower exhaust manifold fasteners (Fig.
113). DO NOT tighten until all fasteners are in place.
(3) Lower vehicle and install upper exhaust mani-
fold fasteners (Fig. 113). Tighten all manifold bolts
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 (Fig.
113). Tighten fasteners to 8 N´m (72 in. lbs.), then
loosen 45 degrees.
(5) Connect exhaust pipe to manifold.
(6) Connect negative cable to battery.
Fig. 113 Exhaust ManifoldÐLeft
ITEM DESCRIPTION TORQUE ITEM DESCRIPTION TORQUE
1 Stud (Qty 2)
25 N´m (18 ft. lbs.)4 Nut (Qty 2) 8 N´m (72 in. lbs.),
then loosen 45
degrees 2 Bolt (Qty 4) 5 Nut (Qty 2)
3 Stud (Qty 2)
DRENGINE - 4.7L 9 - 165
EXHAUST MANIFOLD (Continued)

VALVE TIMING
DESCRIPTIONÐTIMING DRIVE SYSTEM
The timing drive system (Fig. 114) has been
designed to provide quiet performance and reliability
to support anon-free wheelingengine. Specifically
the intake valves are non-free wheeling and can be
easily damaged with forceful engine rotation if cam-
shaft-to-crankshaft timing is incorrect. The timing
drive system consists of a primary chain and two sec-
ondary 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 primarychain receives oil splash lubrication from the second-
ary chain drive and oil pump leakage. The idler
sprocket assembly connects the primary and second-
ary chain drives. The idler sprocket assembly con-
sists 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 station-
ary 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 con-
trol sprocket thrust movement. Pressurized oil is
routed through the center of the idler shaft to pro-
vide lubrication 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 cylinder 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
Fig. 114 Timing Drive System
1 - RIGHT CAMSHAFT SPROCKET AND SECONDARY CHAIN
2 - SECONDARY TIMING CHAIN TENSIONER (LEFT AND RIGHT
SIDE NOT COMMON)
3 - SECONDARY TENSIONER ARM
4 - LEFT CAMSHAFT SPROCKET AND SECONDARY CHAIN
5 - CHAIN GUIDE
6 - TWO PLATED LINKS ON RIGHT CAMSHAFT CHAIN7 - PRIMARY CHAIN
8 - IDLER SPROCKET
9 - CRANKSHAFT SPROCKET
10 - PRIMARY CHAIN TENSIONER
11 - TWO PLATED LINKS ON LEFT CAMSHAFT CHAIN
12 - SECONDARY TENSIONER ARM
9 - 166 ENGINE - 4.7LDR

sprocket assembly. A fixed chain guide and a hydrau-
lic oil damped tensioner are used to maintain tension
in each secondary chain system. The hydraulic ten-
sioners for the secondary chain systems are fed pres-
surized 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 fric-
tion and long wear. The secondary timing chains
receive lubrication from a small orifice in the ten-
sioners. This orifice is protected from clogging by a
fine mesh screen which is located on the back of the
hydraulic tensioners.
STANDARD PROCEDURE
STANDARD PROCEDUREÐMEASURING
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 extension is obtained. Measure the
distance between the secondary timing chain ten-
sioner housing and the step ledge on the piston (Fig.
115). 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 TIMING/
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).
Fig. 115 Measuring Secondary Timing Chains For
Wear
1 - SECONDARY TENSIONER ARM
2 - SECONDARY CHAIN TENSIONER PISTON
DRENGINE - 4.7L 9 - 167
VALVE TIMING (Continued)

(2) Using a mirror, locate the TDC arrow on the
front cover (Fig. 116). Rotate the crankshaft until the
mark on the crankshaft damper is aligned with the
TDC arrow on the front cover. The engine is now at
TDC.
(3) Note the location of the V8 mark stamped into
the camshaft drive gears (Fig. 117). If the V8 mark
on each camshaft drive gear is at the twelve o'clock
position, the engine is at TDC (cylinder #1) on the
exhaust stroke. If the V8 mark on each gear is at the
six o'clock position, the engine is at TDC (cylinder
#1) on the compression stroke.
(4) If both of the camshaft drive gears are off in
the same or opposite directions, the primary chain or
both secondary chains are at fault. Refer to Timing
Chain and Sprockets procedure in this section.
(5) If only one of the camshaft drive gears is off
and the other is correct, the problem is confined to
one secondary chain. Refer to Single camshaft tim-
ing, in this procedure.
(6) If both camshaft drive gear V8 marks are at
the twelve o'clock or the six o' clock position the
engine base timing is correct. Reinstall the cylinder
head covers.
Fig. 116 Engine Top Dead Center (TDC) Indicator
Mark
1 - TIMING CHAIN COVER
2 - CRANKSHAFT TIMING MARKS
Fig. 117 Camshaft Sprocket V8 Marks
1 - LEFT CYLINDER HEAD2 - RIGHT CYLINDER HEAD
9 - 168 ENGINE - 4.7LDR
VALVE TIMING (Continued)

SINGLE CAMSHAFT TIMING
NOTE: to adjust the timing on one camshaft, pre-
form the following procedure.
(1) Using Chain Tensioner Wedge, special tool
8350, stabilize the secondary chain drive (Fig. 118).
For reference purposes, mark the chain-to-sprocket
position (Fig. 118).
(2) Remove the camshaft drive gear retaining bolt.
(3) Carefully remove the camshaft drive gear from
the camshaft.
(4) Re-index the camshaft drive gear in the chain
until the V8 mark is at the same position as the V8
mark on the opposite camshaft drive gear.
NOTE: When gripping the camshaft, place the pliers
on the tube portion of the camshaft only. Do not
grip the lobes or the sprocket areas.
(5) Using a suitable pair of adjustable pliers,
rotate the camshaft until the alignment dowel on the
camshaft is aligned with the slot in the camshaft
drive gear (Fig. 119).
CAUTION: Remove excess oil from camshaft
sprocket retaining bolt before reinstalling bolt. Fail-
ure to do so may cause over-torqueing of bolt
resulting in bolt failure.
Fig. 118 Securing Timing Chain Tensioners Using Timing Chain Wedge
1 - LEFT CYLINDER HEAD
2 - RIGHT CYLINDER HEAD3 - SPECIAL TOOL 8350 WEDGE
4 - SPECIAL TOOL 8350 WEDGE
Fig. 119 Camshaft Dowel
1 - ADJUSTABLE PLIERS
2 - CAMSHAFT DOWEL
DRENGINE - 4.7L 9 - 169
VALVE TIMING (Continued)

(6)Position the camshaft drive gear onto the camshaft,
remove oil from bolt then install the retaining bolt. Using
Special Tools, Spanner Wrench 6958 with Adapter Pins
8346 and a suitable torque wrench, Tighten retaining bolt
to 122N´m (90 ft. Lbs.) (Fig. 120) (Fig. 121).
(7) Remove special tool 8350.
(8) Rotate the crankshaft two full revolutions, then
reverify that the camshaft drive gear V8 marks are
in fact aligned.
(9) Install the cylinder head covers (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
TIMING BELT / CHAIN
COVER(S)
REMOVAL
(1) Disconnect the battery negative cable.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Disconnect both heater hoses at timing cover.(4) Disconnect lower radiator hose at engine.
(5) Remove crankshaft damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(6) Remove accessory drive belt tensioner assembly
(Fig. 122).
Fig. 120 Camshaft Sprocket Left Cylinder Head
1 - TORQUE WRENCH
2 - CAMSHAFT SPROCKET
3 - LEFT CYLINDER HEAD
4 - SPECIAL TOOL 6958 SPANNER WITH ADAPTER PINS 8346
Fig. 121 Camshaft Sprocket InstallationÐRight
Cylinder Head
1 - TORQUE WRENCH
2 - SPECIAL TOOL 6958 WITH ADAPTER PINS 8346
3 - LEFT CAMSHAFT SPROCKET
4 - RIGHT CAMSHAFT SPROCKET
Fig. 122 Accessory Drive Belt Tensioner
1 - TENSIONER ASSEMBLY
2 - FASTENER TENSIONER TO FRONT COVER
9 - 170 ENGINE - 4.7LDR
VALVE TIMING (Continued)