1998 DODGE RAM 1500 Egr

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

(13) Remove left and right camshaft sprocket bolts.
(14) While holding the left camshaft steel tube
with adjustable pliers, (Fig. 131) remove the left
camshaft sprocket. Slowly rotate the camshaft
approximately 15 degrees clockwise to a neutral posi-
tion.
(15) While holding the right camshaft steel tube
with adjustable pliers, (Fig. 132) remove the right
camshaft sprocket. Slowly rotate the camshaft
approximately 45 degrees counterclockwise to a neu-
tral position.
(16) Remove idler sprocket assembly bolt.
(17) Slide the idler sprocket assembly and crank
sprocket forward simultaneously to remove the pri-
mary and secondary chains.
(18) Remove both pivoting tensioner arms and
chain guides.
(19) Remove chain tensioner.
INSPECTION
Inspect the following components:
²Sprockets for excessive tooth wear. Some tooth
markings are normal and not a cause for sprocket
replacement.
²Idler sprocket assembly bushing and shaft for
excessive wear.
²Idler sprocket assembly spline joint. The joint
should be tight with no backlash or axial movement.
²Chain guides and tensioner arms. Replace these
parts if grooving in plastic face is more than 1 mm
(0.039 in.) deep. If plastic face is severely grooved or
melted, the tensioner lube jet may be clogged. The
tensioner should be replaced.
²Secondary chain tensioner piston and ratcheting
device. Inspect for evidence of heavy contact between
tensioner piston and tensioner arm. If this condition
exist the tensioner and tensioner arm should be
replaced.
²Primary chain tensioner plastic faces. Replace as
required (Fig. 133).
Fig. 131 Camshaft RotationÐLeft Side
1 - CAMSHAFT SPROCKET AND CHAIN
2 - ADJUSTABLE PLIERS
3 - CAMSHAFT
Fig. 132 Camshaft RotationÐRight Side
1 - ADJUSTABLE PLIERS
2 - CAMSHAFT DOWEL
9 - 174 ENGINE - 4.7LDR
TIMING BELT/CHAIN AND SPROCKETS (Continued)

CAUTION: The head gaskets are marked ªTOPº to
indicate which side goes up.
(4) Position cylinder heads onto head gaskets and
cylinder block.
(5) Tighten the cylinder head bolts in three steps
(Fig. 4):
²Step 1Ð Snug tighten M12 cylinder head bolts,
in sequence, to 34 N´m (25 ft. lbs.) and M8 bolts to
20 N´m (15 ft. lbs.) torque.
²Step 2Ð Tighten M12 cylinder head bolts, in
sequence, to 54 N´m (40 ft. lbs.) and verify M8 bolts
to 20 N´m (15 ft. lbs.) torque..
²Step 3Ð Turn M12 cylinder head bolts, in
sequence, 90 degrees and tighten M8 bolts to 34 N´m
(25 ft. lbs.) torque.
(6) Install push rods and rocker arm assemblies in
their original position.
(7) Install the intake manifold and throttle body
assembly.
(8) If required, adjust spark plugs to specifications.
Install the plugs.
(9) Connect the heater hoses.
(10) Install the fuel supply line.
(11) Install the generator and drive belt.
(12) Install cylinder head covers(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(13) Connect the evaporation control system.
(14) Install the air cleaner.
(15) Fill cooling system.
(16) Connect the negative cable to the battery.
(17) Start engine check for leaks.CYLINDER HEAD COVER(S)
REMOVAL
(1) Disconnect battery negative cable.
(2) Disconnect coil on plug connectors.
CAUTION: The ground straps must be installed in
the same location as removed. The covers are
machined to accept the ground straps in those
locations only.
(3) Remove cylinder head cover retaining bolts,
and ground straps.
(4) Remove cylinder head cover.
NOTE: The gasket may be used again, provided no
cuts, tears, or deformation has occurred.
INSTALLATION
CAUTION: Do not use harsh cleaners to clean the
cylinder head covers. Severe damage to covers
may occur.
CAUTION: DO NOT allow other components includ-
ing the wire harness to rest on or against the
engine cylinder head cover. Prolonged contact with
other objects may wear a hole in the cylinder head
cover.
(1) Clean cylinder head cover and both sealing sur-
faces. Inspect and replace gasket as necessary.
(2)
Install cylinder head cover and hand start all fas-
teners. Verify that all double ended studs are in the cor-
rect location and install left and right ground straps.
CAUTION: The ground straps must be installed in
the same location as removed. The covers are
machined to accept the ground straps in those
locations only.
NOTE: The right hand ground strap is located on
the front inboard stud. The left hand ground strap
is located on the rear inboard stud.
(3) Tighten cylinder head cover bolts and double
ended studs to 8 N´m (70 in. lbs). Begin torque
sequence in the middle of head cover and torque
bolts moving outward in a crisscross pattern from top
to bottom.
(4) Install ignition coil on plug, and torque fasten-
ers to 12 N´m (105 in. lbs)
(5) Connect, ignition coil electrical connectors.
(6) Install PCV hose.
(7) Connect battery negative cable.
Fig. 4 CYLINDER HEAD TIGHTENING SEQUENCE
DRENGINE - 5.7L 9 - 201
CYLINDER HEAD (Continued)

INTAKE/EXHAUST VALVES &
SEATS
DESCRIPTION
DESCRIPTION - VALVE GUIDES
The valve guides are made of powered metal and
are pressed into the cylinder head. The guides are
not replaceable or serviceable, and valve guide ream-
ing is not recommended. If the guides are worn
beyond acceptable limits, replace the cylinder heads.
DESCRIPTION
Both the intake and exhaust valves are made of
steel. The intake valve is 50.93 mm (2.00 inches) in
diameter and the exhaust valve is 39.53 mm (1.55
inches) in diameter. All valves use three bead lock
keepers to retain the springs and promote valve rota-
tion.
STANDARD PROCEDURE - REFACING
NOTE: Valve seats that are worn or burned can be
reworked, provided that correct angle and seat
width are maintained. Otherwise the cylinder head
must be replaced.
NOTE: When refacing valves and valve seats, it is
important that the correct size valve guide pilot be
used for reseating stones. A true and complete sur-
face must be obtained.
(1) Using a suitable dial indicator measure the
center of the valve seat Total run out must not
exceed 0.051 mm (0.002 in).
(2) Apply a small amount of Prussian blue to the
valve seat, insert the valve into the cylinder head,
while applying light pressure on the valve rotate the
valve. Remove the valve and examine the valve face.
If the blue is transferred below the top edge of the
valve face, lower the valve seat using a 15 degree
stone. If the blue is transferred to the bottom edge of
the valve face, raise the valve seat using a 65 degree
stone.
(3) When the seat is properly positioned the width
of the intake seat must be 1.018 - 1.62 mm (0.0464 -
0.0637 in.) and the exhaust seat must be 1.48 - 1.92
mm (0.058 - 0.075 in.).
(4) Check the valve spring installed height after
refacing the valve and seat. The installed height for
both intake and exhaust valve springs must not
exceed 46.0 mm (1.81 in.).
VALVE FACE AND VALVE SEAT ANGLE CHART
DESCRIPTION SPECIFICATION
SEAT WIDTH
INTAKE 1.018 - 1.62 mm
(0.0464 - 0.0637 in.)
EXHAUST 1.48 - 1.92 mm
(0.058 - 0.075 in.)
FACE ANGLE
(INT. AND EXT.) 45É - 45
1¤2É
SEAT ANGLE
(INT. AND EXT.) 44
1¤2É - 45É
(5)
The valve seat must maintain an angle of 44.5 ±
45.0 degrees angle.
(6) The valve face must maintain a face angle of
45.0 ± 45.5 degrees angle (Fig. 5).
Fig. 5 Valve Assembly Configuration
1 - VALVE LOCKS (3±BEAD)
2 - RETAINER
3 - VALVE STEM OIL SEAL
4 - INTAKE VALVE
5 - EXHAUST VALVE
6 - VALVE SPRING
9 - 202 ENGINE - 5.7LDR

REMOVAL
(1) Remove the cylinder head (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(2) Compress valve springs using Valve Spring
Compressor Tool special tool # C-3422and adapter
8464.
(3) Remove valve retaining locks, valve spring
retainers, valve stem seals and valve springs.
(4) Before removing valves, remove any burrs from
valve stem lock grooves to prevent damage to the
valve guides. Identify valves to ensure installation in
original location.
INSTALLATION
(1) Clean valves thoroughly. Discard burned,
warped and cracked valves.
(2) Remove carbon and varnish deposits from
inside of valve guides with a reliable guide cleaner.
(3) Measure valve stems for wear. If wear exceeds
0.051 mm (0.002 inch), replace the valve.
(4) Coat valve stems with lubrication oil and insert
them in cylinder head.
(5) If valves or seats are reground, check valve
stem height. If valve is too long, replace cylinder
head.
(6) Install new seals on all valve guides. Install
valve springs and valve retainers.
(7) Compress valve springs with Valve Spring
Compressor Tool special tool # C- 3422and adapter
8464, install locks and release tool. If valves and/or
seats are ground, measure the installed height of
springs. Make sure the measurement is taken from
bottom of spring seat in cylinder head to the bottom
surface of spring retainer.
(8) Install cylinder head (Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
ROCKER ARM / ADJUSTER
ASSY
REMOVAL
(1) Remove cylinder head cover.(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL)
(2) Loosen the rocker shafts using the following
sequence:Center, center-left, center-right, left,
right,.
CAUTION: The rocker shaft assemblies are not
interchangeable between intake and exhaust. The
intake rocker arms are marked with an ªIº.
(3) Remove the rocker shafts. Note location for
reassembly.CAUTION: The longer push rods are for the exhaust
side, and the shorter push rods are for intake side.
(4) Remove the pushrods. Note pushrod location
for reassembly.
INSTALLATION
CAUTION: The longer push rods are for the exhaust
side, and the shorter push rods are for intake side.
(1) Install the push rods in the same order as
removed.
CAUTION: Verify that pushrod is installed into
rocker arm and lifter correctly while installing
rocker shaft assembly. Recheck after rocker shaft
has been torqued to specification.
CAUTION: The rocker shaft assemblies are not
interchangeable between intake and exhaust. The
intake rocker arms are marked with the letter ªIº.
(2) Install rocker shaft assemblies in the same
order as removed.
CAUTION: Ensure that hold downs and rocker arms
are not overlapped when torquing bolts.
(3) Tighten the rocker shaft bolts to 22 N´m (195
in. lbs.) torque,using the following sequence:Center,
center-right, center-left, right, left.
CAUTION: DO NOT rotate or crank the engine dur-
ing or immediately after rocker arm installation.
Allow the hydraulic roller tappets adequate time to
bleed down (about 5 minutes).
(4) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
VALVE STEM SEALS
DESCRIPTION
The valve guide seals are made of rubber and
incorporate an integral steel valve spring seat. The
integral garter spring maintains consistent lubrica-
tion control to the valve stems.
DRENGINE - 5.7L 9 - 203
INTAKE/EXHAUST VALVES & SEATS (Continued)

ENGINE BLOCK
CLEANING
Thoroughly clean the oil pan and engine block gas-
ket surfaces.
Use compressed air to clean out:
²The galley at the oil filter adaptor hole.
²The front and rear oil galley holes.
²The feed holes for the crankshaft main bearings.
Once the block has been completely cleaned, apply
Loctite PST pipe sealant with Teflon 592 to the
threads of the front and rear oil galley plugs. Tighten
the 1/4 inch NPT plugs to 20 N´m (177 in. lbs.)
torque. Tighten the 3/8 inch NPT plugs to 27 N´m
(240 in. lbs.) torque.
INSPECTION
(1) It is mandatory to use a dial bore gauge to
measure each cylinder bore diameter. To correctly
select the proper size piston, a cylinder bore gauge,
capable of reading in 0.003 mm (.0001 in.) INCRE-
MENTS is required. If a bore gauge is not available,
do not use an inside micrometer (Fig. 7).
(2) Measure the inside diameter of the cylinder
bore at three levels below top of bore. Start perpen-
dicular (across or at 90 degrees) to the axis of the
crankshaft and then take two additional reading.
(3) Measure the cylinder bore diameter crosswise
to the cylinder block near the top of the bore. Repeatthe measurement near the middle of the bore, then
repeat the measurement near the bottom of the bore.
(4) Determine taper by subtracting the smaller
diameter from the larger diameter.
(5) Rotate measuring device 90É and repeat steps
above.
(6) Determine out-of-roundness by comparing the
difference between each measurement.
(7) If cylinder bore taper does not exceed 0.025
mm (0.001 inch) and out-of-roundness does not
exceed 0.025 mm (0.001 inch), the cylinder bore can
be honed. If the cylinder bore taper or out- of-round
condition exceeds these maximum limits, the cylinder
block must be replaced. A slight amount of taper
always exists in the cylinder bore after the engine
has been in use for a period of time.CAMSHAFT & BEARINGS (IN
BLOCK)
REMOVAL
REMOVAL - CAMSHAFT CORE HOLE PLUG
CAUTION: Do not damage the rear surface of the
camshaft or the core plug sealing surface, when
removing the core plug.
(1) Remove the rear cam bearing core plug.
REMOVAL - CAMSHAFT
(1) Remove the battery negative cable.
(2) Remove the air cleaner assembly.
(3) Drain coolant.
(4) Remove the accessory drive belt.
(5) Remove the generator.
(6) Remove the A/C compressor, and set aside
(7) Remove the radiator (Refer to 7 - COOLING/
ENGINE/RADIATOR - REMOVAL).
(8) Remove intake manifold(Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
(9) Remove cylinder head covers(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(10) Remove both left and right cylinder heads(Re-
fer to 9 - ENGINE/CYLINDER HEAD - REMOVAL) .
(11) Remove the oil pan(Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL).
(12) Remove timing case cover(Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(13) Remove the oil pick up tube.
(14) Remove the oil pump(Refer to 9 - ENGINE/
LUBRICATION/OIL PUMP - REMOVAL).
Fig. 7 BORE GAUGE-TYPICAL
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4 - 38 MM (1.5 in)
DRENGINE - 5.7L 9 - 205

REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Remove the air cleaner(Refer to 9 - ENGINE/
AIR INTAKE SYSTEM - REMOVAL).
(3) Remove intake manifold(Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
(4) Remove cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(5) Remove rocker arm assembly and push rod-
s(Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - REMOVAL). Identify
push rods to ensure installation in original location.
(6) Remove the cylinder head(Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(7) Remove bolt from tappet guide holder.
(8) Remove tappet guide holder.
(9) Pull tappet out of bore with a twisting motion.
If all tappets are to be removed and reused, identify
tappets to ensure installation in original location.
(10) Check camshaft lobes for abnormal wear.
INSTALLATION
(1) Lubricate tappets.
(2) Install tappets in their original positions.
(3)
Install tappet guide holder. Install the tappet
guide holder bolt and tighten to 12 N´m (106 in. lbs.)
torque.
(4) Install cylinder head(Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
(5) Install pushrods and rocker arm assembly(Re-
fer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - INSTALLATION).
(6) Install cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(7)
Install intake manifold(Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - INSTALLATION).
(8) Install the air cleaner(Refer to 9 - ENGINE/
AIR INTAKE SYSTEM - INSTALLATION).
(9) Connect the negative cable to the battery.
CAUTION: To prevent damage to valve mechanism,
engine must not be run above fast idle until all
hydraulic tappets have filled with oil and have
become quiet.
(10) Road test vehicle and check for leaks.
PISTON & CONNECTING ROD
DESCRIPTION
CAUTION: Do not use a metal stamp to mark con-
necting rods as damage may result, instead use ink
or a scratch awl.The pistons are made of a high strength aluminum
alloy. Piston skirts are coated with a solid lubricant
(Molykote) to reduce friction and provide scuff resis-
tance. The piston top ring groove and land is anod-
ized. The connecting rods are made of forged
powdered metal, with a ªfractured capº design. A
pressed fit piston pin is used to attach the piston and
connecting rod.
STANDARD PROCEDUREÐPISTON FITTING
(1) To correctly select the proper size piston, a cyl-
inder bore gauge, 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.
(2) Measure the inside diameter of the cylinder
bore 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 (Fig. 11).
(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) The coating material is applied to the piston
after the final piston machining process. Measuring
the outside diameter of a coated piston will not pro-
vide accurate results (Fig. 10). Therefore measuring
the inside diameter of the cylinder bore with a dial
Bore Gauge isMANDATORY. To correctly select the
proper size piston, a cylinder bore gauge capable of
reading in 0.003 mm (.0001 in.) increments is
required.
Fig. 10 MOLY COATED PISTON
1 - MOLY COATED
2 - MOLY COATED
DRENGINE - 5.7L 9 - 211
HYDRAULIC TAPPETS (Continued)

(8) Torque the (3) bolts that attach the front axle
to the left engine bracket to 101 N´m (75 ft. lbs.).
(9) Install the engine oil filter, if removed.
(10) Install the front crossmember(Refer to 13 -
FRAME & BUMPERS/FRAME/FRONT CROSS-
MEMBER - INSTALLATION).
(11) Install the skid plate.
(12) Lower the vehicle.
(13) Reconnect the negative battery cable.
REAR MOUNT
REMOVAL
(1) Raise the vehicle on a hoist.
(2) Using a suitable jack, support transmission.
(3) Remove the nuts from the transmission mount
(Fig. 26).
(4) Remove the two bolts that attach the transmis-
sion mount to the engine bracket.
(5) Raise the transmission enough to remove the
mount from the crossmember.
(6) Remove the mount.
INSTALLATION
NOTE: Threadlocking compound must be applied to
the bolts before installation.(1) Install the two bolts that attach the transmis-
sion mount to the transmission bracket.
(2) Torque the bolts to 61N´m (45 ft.lbs.) torque.
(3) Lower the transmission so the transmission
mount rests on the crossmember, and the studs of
the transmission mount are aligned in the slots in
the crossmember.
(4) Install the nuts onto the transmission mount
studs through the crossmember access slot.
(5) Torque the nuts to 54N´m (40 ft. lbs.).
LUBRICATION
DESCRIPTION
The lubrication system (Fig. 27) is a full flow fil-
tration pressure feed type.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - CHECKING
ENGINE OIL PRESSURE
(1) Remove oil pressure sending unit and install
gauge assembly C-3292.
(2) Run engine until thermostat opens.
(3) Oil Pressure:
²Curb Idle±25 kPa (4 psi) minimum
²3000 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.
DIAGNOSIS AND TESTING - ENGINE OIL LEAK
Begin with a thorough visual inspection of the
engine, particularly at the area of the suspected leak.
If an oil leak source is not readily identifiable, the
following steps should be followed:
(1) Do not clean or degrease the engine at this
time because some solvents may cause rubber to
swell, temporarily stopping the leak.
(2) Add an oil soluble dye (use as recommended by
manufacturer). Start the engine and let idle for
approximately 15 minutes. Check the oil dipstick to
make sure the dye is thoroughly mixed as indicated
with a bright yellow color under a black light.
(3) Using a black light, inspect the entire engine
for fluorescent dye, particularly at the suspected area
of oil leak. If the oil leak is found and identified,
repair per service manual instructions.
(4) If dye is not observed, drive the vehicle at var-
ious speeds for approximately 24 km (15 miles), and
repeat inspection.If the oil leak source is not pos-
itively identified at this time, proceed with the air
leak detection test method.
Fig. 26 TRANSMISSION MOUNT
1 - MOUNT
2 - CROSSMEMBER
3 - NUT
4 - BOLT
9 - 220 ENGINE - 5.7LDR
FRONT MOUNT (Continued)