1998 DODGE RAM 1500 Workshop Manual

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Page 1385 of 2627

DODGE RAM 1500 1998 2.G Workshop Manual 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 (Qt

Page 1386 of 2627

DODGE RAM 1500 1998 2.G Workshop Manual 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 f

Page 1387 of 2627

DODGE RAM 1500 1998 2.G Workshop Manual 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 a

Page 1388 of 2627

DODGE RAM 1500 1998 2.G Workshop Manual 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.
(

Page 1389 of 2627

DODGE RAM 1500 1998 2.G Workshop Manual 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 in

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

Page 1390 of 2627

DODGE RAM 1500 1998 2.G Workshop Manual 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 ar

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)

Page 1391 of 2627

DODGE RAM 1500 1998 2.G Workshop Manual (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 no

Page 1392 of 2627

DODGE RAM 1500 1998 2.G Workshop Manual 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)

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