
TESTING VALVE SPRINGS
NOTE: Whenever the valves are removed from the
cylinder head it is recommended that the valve
springs be inspected and tested for reuse.
Inspect the valve springs for physical signs of wear
or damage. Turn table of tool C-647 until surface is
in line with the 40.69 mm (1.602 in.) mark on the
threaded stud and the zero mark on the front. Place
spring over the stud on the table and lift compress-
ing lever to set tone device. Pull on torque wrench
until Ping is heard. Take reading on torque wrench
at this instant. Multiply this reading by two. This
will give the spring load at test length. Fractional
measurements are indicated on the table for finer
adjustments. Refer to Specifications Section to obtain
specified height and allowable tensions. Replace any
springs that do not meet specifications (Fig. 19).
INSTALLATION
(1) coat the valve stem with clean engine oil and
insert it into the cylinder head.
(2) Install the valve stem seal. make sure the seal
is fully seated and that the garter spring at the top
of the seal is intact.
(3) Install the spring and the spring retainer (Fig.
20).
(4) Using the valve spring compressor, compress
the spring and install the two valve spring retainer
halves.(5) Release the valve spring compressor and make
sure the two spring retainer halves and the spring
retainer are fully seated.
(6) lubricate the camshaft journal with clean
engine oil then Position the camshaft (with the
sprocket dowel on the left camshaft at 11 o'clock and
the right camshaft at 12 o'clock), then position the
camshaft bearing caps.
(7) Install the camshaft bearing cap retaining
bolts. Tighten the bolts 9±13 N´m (100 in. lbs.) in ó
turn increments in the sequence shown (Fig. 21).
(8) Position the hydraulic lash adjusters and
rocker arms.
Fig. 19 Testing Valve Springs
1 - SPECIAL TOOL C-647
Fig. 20 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 - 28 ENGINE - 3.7LKJ
INTAKE/EXHAUST VALVES & SEATS (Continued)

NOTE: Check for sharp edges on the keeper
grooves. Remove any burrs from the valve stem
before removing the valve from the cylinder head.
(7) Remove the valve from the cylinder head.
NOTE: The valve stem seals are common between
intake and exhaust.
(8) Remove the valve stem seal. Mark the valve for
proper installation.
TESTING VALVE SPRINGS
NOTE: Whenever the valves are removed from the
cylinder head it is recommended that the valve
springs be inspected and tested for reuse.
Inspect the valve springs for physical signs of wear
or damage. Turn table of tool C-647 until surface is
in line with the 40.69 mm (1.602 in.) mark on the
threaded stud and the zero mark on the front. Place
spring over the stud on the table and lift compress-
ing lever to set tone device. Pull on torque wrench
until Ping is heard. Take reading on torque wrench
at this instant. Multiply this reading by two. This
will give the spring load at test length. Fractional
measurements are indicated on the table for finer
adjustments. Refer to Specifications Section to obtain
specified height and allowable tensions. Replace any
springs that do not meet specifications (Fig. 26).
INSTALLATION
(1) coat the valve stem with clean engine oil and
insert it into the cylinder head.
(2) Install the valve stem seal. make sure the seal
is fully seated and that the garter spring at the top
of the seal is intact.
(3) Install the spring and the spring retainer.
(4) Using the valve spring compressor, compress
the spring and install the two valve spring retainer
halves (Fig. 27).
(5) Release the valve spring compressor and make
sure the two spring retainer halves and the spring
retainer are fully seated.
(6) lubricate the camshaft journal with clean
engine oil then Position the camshaft (with the
sprocket dowel on the left camshaft at 11 o'clock and
the right camshaft at 12 o'clock), then position the
camshaft bearing caps.
(7) Install the camshaft bearing cap retaining
bolts. Tighten the bolts 9±13 N´m (100 in. lbs.) in ó
turn increments in the sequence shown (Fig. 28).
(8) Position the hydraulic lash adjusters and
rocker arms.
Fig. 26 Testing Valve Springs
1 - SPECIAL TOOL C-647
Fig. 27 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 - 36 ENGINE - 3.7LKJ
INTAKE/EXHAUST VALVES & SEATS (Continued)

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 plugs to 34 N´m (25 ft. 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. 33).
(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. Repeat
the 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.
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - CONNECTING ROD
BEARING - FITTING
Inspect the connecting rod bearings for scoring and
bent alignment tabs (Fig. 34) (Fig. 35). Check the
bearings for normal wear patterns, scoring, grooving,
fatigue and pitting (Fig. 36). Replace any bearing
that shows abnormal wear.
Inspect the connecting rod journals for signs of
scoring, nicks and burrs.
Fig. 33 Bore GaugeÐTypical
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4 - 38 MM (1.5 in)
Fig. 34 Connecting Rod Bearing Inspection
1 - UPPER BEARING HALF
2 - MATING EDGES
3 - GROOVES CAUSED BY ROD BOLTS SCRATCHING
JOURNAL DURING INSTALLATION
4 - WEAR PATTERN Ð ALWAYS GREATER ON UPPER
BEARING
5 - LOWER BEARING HALF
9 - 40 ENGINE - 3.7LKJ
ENGINE BLOCK (Continued)

(1) Position the engine exhaust manifold and gas-
ket on the two studs located on the cylinder head.
Install conical washers and nuts on these studs.
(2) Install remaining conical washers. Starting at
the center arm and working outward, tighten the
bolts and nuts to 25 N´m (18 ft. lbs.) torque.
(3) Install the exhaust heat shields.
(4) Raise and support the vehicle.
CAUTION: Over tightening heat shield fasteners,
may cause shield to distort and/or crack.
(5) Assemble exhaust pipe to manifold and secure
with bolts, nuts and retainers. Tighten the bolts and
nuts to 34 N´m (25 ft. lbs.) torque.
LEFT EXHAUST MANIFOLD
CAUTION: If the studs came out with the nuts when
removing the engine exhaust manifold, install new
studs. Apply sealer on the coarse thread ends.
Water leaks may develop at the studs if this precau-
tion is not taken.
(1) Position the engine exhaust manifold and gas-
ket on the two studs located on the cylinder head.
Install conical washers and nuts on these studs.
(2) Install remaining conical washers. Starting at
the center arm and working outward, tighten the
bolts and nuts to 25 N´m (18 ft. lbs.) torque.
(3) Install the exhaust heat shields.
(4) Raise and support the vehicle.
CAUTION: Over tightening heat shield fasteners,
may cause shield to distort and/or crack.
(5) Assemble exhaust pipe to manifold and secure
with bolts, nuts and retainers. Tighten the bolts and
nuts to 34 N´m (25 ft. lbs.) torque.
VALVE TIMING
DESCRIPTION
The timing drive system has been designed to pro-
vide quiet performance and reliability to support a
non-free wheelingengine. Specifically the intake
valves are non-free wheeling and can be easily dam-
aged with forceful engine rotation if camshaft-to-
crankshaft timing is incorrect. The timing drive
system consists of a primary chain, two secondary
timing chain drives and a counterbalance shaft drive.
OPERATION
The primary timing chain is a single inverted tooth
chain type. The primary chain drives the large 40
tooth idler sprocket directly from a 20 tooth crank-shaft 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 pri-
mary chain receives oil splash lubrication from the
secondary chain drive and designed oil pump leak-
age. The idler sprocket assembly connects the pri-
mary chain drive, secondary chain drives, and the
counterbalance shaft. The idler sprocket assembly
consists of two integral 26 tooth sprockets a 40 tooth
sprocket and a helical gear that is press-fit to the
assembly. The spline joint for the 40 tooth sprocket is
a non ± serviceable press fit anti rattle type. A spiral
ring is installed on the outboard side of the fifty
tooth sprocket to prevent spline disengagement. The
idler sprocket assembly spins on a stationary idler
shaft. The idler shaft is a light press-fit into the cyl-
inder 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
roller 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 26 tooth cam sprocket directly from
the 26 tooth sprocket on the idler sprocket assembly.
A fixed chain guide and a hydraulic oil damped ten-
sioner are used to maintain tension in each second-
ary chain system. The hydraulic tensioners for the
secondary chain systems are fed pressurized oil from
oil reservoir pockets in the block. Each tensioner
incorprates a controled leak path through a device
known as a vent disc located in the nose of the piston
to manage chain loads. 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 pro-
tected from clogging by a fine mesh screen which is
located on the back of the hydraulic tensioners.
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 Timing
Chain Cover in this section for procedure.
KJENGINE - 3.7L 9 - 71
EXHAUST MANIFOLD (Continued)

CAUTION: Care should be taken not to damage
camshaft target wheel. Do not hold target wheel
while loosening or tightening camshaft sprocket.
Do not place the target wheel near a magnetic
source of any kind. A damaged or magnetized tar-
get wheel could cause a vehicle no start condition.
CAUTION: Do not forcefully rotate the camshafts or
crankshaft independently of each other. Damaging
intake valve to piston contact will occur. Ensure
negative battery cable is disconnected to guard
against accidental starter engagement.
(13) Remove left and right camshaft sprocket bolts.
(14) While holding the left camshaft steel tube
with Special Tool 8428 Camshaft Wrench, remove the
left camshaft sprocket. Slowly rotate the camshaft
approximately 5 degrees clockwise to a neutral posi-
tion.
(15) While holding the right camshaft steel tube
with Special Tool 8428 Camshaft Wrench, remove the
right camshaft sprocket.
(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 tensioner arm and chain should
be replaced.
²Primary chain tensioner plastic faces. Replace as
required.
Fig. 105 CAMSHAFT POSITION SENSOR
1 - CYLINDER HEAD
2 - CAMSAHFT POSITION SENSOR
2 - SCREW
Fig. 106 Crankshaft Position Sensor
1 - CRANKSHAFT POSITION SENSOR
2 - CYLINDER HEAD COVER
3 - CAMSHAFT POSITION SENSOR
4 - RIGHT SIDE CYLINDER BLOCK
KJENGINE - 3.7L 9 - 79
TIMING BELT/CHAIN AND SPROCKET(S (Continued)

INSTALLATION
(1) Using a vise, lightly compress the secondary
chain tensioner piston until the piston step is flush
with the tensioner body. Using a pin or suitable tool,
release ratchet pawl by pulling pawl back against
spring force through access hole on side of tensioner.
While continuing to hold pawl back, Push ratchet
device to approximately 2 mm from the tensioner
body. Install Special Tool 8514 lock pin into hole on
front of tensioner (Fig. 107). Slowly open vise to
transfer piston spring force to lock pin.
(2) Position primary chain tensioner over oil pump
and insert bolts into lower two holes on tensioner
bracket. Tighten bolts to 28 N´m (250 in. lbs.).
(3) Install right side chain tensioner arm. Apply
MopartLock N, Seal to torxtbolt, tighten bolt to 28
N´m (250 in. lbs.).
CAUTION: The silver bolts retain the guides to the
cylinder heads and the black bolts retain the guides
to the engine block.
(4) Install the left side chain guide. Tighten the
bolts to 28 N´m (250 in. lbs.).
(5) Install left side chain tensioner arm. Apply
MopartLock N, Seal to torxtbolt, tighten bolt to 28
N´m (250 in. lbs.).(6) Install the right side chain guide. Tighten the
bolts to 28 N´m (250 in. lbs.).
(7) Install both secondary chains onto the idler
sprocket. Align two plated links on the secondary
chains to be visible through the two lower openings
on the idler sprocket (4 o'clock and 8 o'clock). Once
the secondary timing chains are installed, position
special tool 8429 to hold chains in place for installa-
tion.
(8) Align primary chain double plated links with
the timing mark at 12 o'clock on the idler sprocket.
Align the primary chain single plated link with the
timing mark at 6 o'clock on the crankshaft sprocket.
(9) Lubricate idler shaft and bushings with clean
engine oil.
NOTE: The idler sprocket must be timed to the
counterbalance shaft drive gear before the idler
sprocket is fully seated.
(10) Install all chains, crankshaft sprocket, and
idler sprocket as an assembly (Fig. 108). After guid-
ing both secondary chains through the block and cyl-
inder head openings, affix chains with a elastic strap
or the equivalent, This will maintain tension on
chains to aid in installation. Align the timing mark
on the idler sprocket to the timing mark on the coun-
terbalance shaft drive gear, then seat idler sprocket
fully (Fig. 109). Before installing idler sprocket bolt,
lubricate washer with oil, and tighten idler sprocket
assembly retaining bolt to 34 N´m (25 ft. lbs.).
Fig. 107 Resetting Secondary Chain Tensioners
1 - VISE
2 - INSERT LOCK PIN
3 - RATCHET PAWL
4 - RATCHET
5 - PISTON
Fig. 108 Installing Idler Gear, Primary and
Secondary Timing Chains
1 - SPECIAL TOOL 8429
2 - PRIMARY CHAIN IDLER SPROCKET
3 - CRANKSHAFT SPROCKET
9 - 80 ENGINE - 3.7LKJ
TIMING BELT/CHAIN AND SPROCKET(S (Continued)

SPECIFICATIONS - TORQUE
DESCRIPTION N´m Ft. Lbs. In. Lbs.
ENGINE CRADLE CROSSMEMBER INNER RAIL BOLTS 47 35 Ð
ENGINE CRADLE CROSSMEMBER MOUNTING BOLTS 122 90 Ð
ENGINE MOUNT THROUGH BOLTS/NUTS 88 65 Ð
FRONT SKID PLATE BOLTS 61 45 Ð
FRONT TOW HOOK NUTS/BOLT 61 45 Ð
FUEL TANK SKID PLATE 88 65 Ð
REAR CROSSMEMBER BOLTS 47 35 Ð
REAR TOW HOOK BOLTS 88 65 Ð
TRAILER HITCH BOLTS 88 65 Ð
TRANSFER CASE SKID PLATE BOLTS 34 25 Ð
TRANSMISSION MOUNT THROUGH BOLT/NUT 88 65 Ð
FRONT SKID PLATE
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the skid plate bolts and remove the
skid plate. (Fig. 7)
INSTALLATION
(1) Install the skid plate.
(2) Install the bolts and tighten to 61 N´m (45 ft.
lbs.).
ENGINE CRADLE
CROSSMEMBER
REMOVAL
(1) Install a suitable engine support tool.
(2) Raise and support the vehicle.
(3) Remove the lower control arms. (Refer to 2 -
SUSPENSION/FRONT/LOWER CONTROL ARM -
REMOVAL)
(4) Remove the sway bar. (Refer to 2 - SUSPEN-
SION/FRONT/STABILIZER BAR - REMOVAL)
(5) Remove the front axle, if equipped. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/FRONT AXLE -
REMOVAL)
(6) Remove the power steering rack. (Refer to 19 -
STEERING/GEAR - REMOVAL)
(7) Loosen the engine mount through bolts.
(8) Support the engine cradle with a suitable lift-
ing device.
(9) Using a grease pencil or equivalent, mark the
location of the engine support cradle.
(10) Remove the engine cradle bolts and remove
the engine cradle.
INSTALLATION
(1) Raise and support the vehicle.
(2) Using a suitable lifting device raise the engine
cradle into the vehicle while lining up the engine
mount through bolts.
Fig. 7 SKID PLATE
1 - SKID PLATE
2 - BOLTS (4)
13 - 6 FRAMES & BUMPERSKJ
FRAME (Continued)

(3) Align the engine cradle to the marks made dur-
ing removal and install the mounting and inner rail
bolts.
(4) Tighten the mounting bolts to 122 N´m (90 ft.
lbs.).
(5) Tighten the inner rail bolts to 47 N´m (35 ft.
lbs.).
(6) Tighten the engine mount through bolts to 88
N´m (65 ft. lbs.).
(7) Install the power steering rack. (Refer to 19 -
STEERING/GEAR - INSTALLATION)
(8) Install the front axle, if equipped. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/FRONT AXLE -
INSTALLATION)
(9) Install the stabilizer bar. (Refer to 2 - SUS-
PENSION/FRONT/STABILIZER BAR - INSTALLA-
TION)
(10) Install the lower control arms. (Refer to 2 -
SUSPENSION/FRONT/LOWER CONTROL ARM -
INSTALLATION)
(11) Lower the vehicle and remove the engine sup-
port tool.
TRANSFER CASE SKID PLATE
REMOVAL
(1) Remove the bolts and remove the skid plate.
(Fig. 8)
INSTALLATION
(1) Install the skid plate.
(2) Install the bolts and tighten to 34 N´m (25 ft.
lbs.).
REAR CROSSMEMBER
REMOVAL
(1) Raise and support the vehicle.
(2) Support the transmission with a suitable lifting
device.
(3) Remove the transmission mount through bolt.
(4) Remove the crossmember bolts and remove the
crossmember. (Fig. 9)
INSTALLATION
(1) Install the crossmember and install the bolts.
(2) Tighten the bolts to 47 N´m (35 ft. lbs.)
(3) Install transmission mount through bolt and
tighten to 88 N´m (65 ft. lbs.).
Fig. 8 SKID PLATE
1 - SKID PLATE
2 - BOLTS
Fig. 9 CROSS MEMBER
1 - CROSSMEMBER
2 - BOLTS
KJFRAMES & BUMPERS 13 - 7
ENGINE CRADLE CROSSMEMBER (Continued)