1995 JEEP XJ engine

PREFERRED METHOD:
(1) Remove the valve from the head.
(2) Clean the valve stem guide bore with solvent
and a bristle brush.
(3) Insert a telescoping gauge into the valve stem
guide bore approximately 9.525 mm (.375 inch) from
the valve spring side of the head (Fig. 10).
(4) Remove and measure telescoping gauge with a
micrometer.
(5) Repeat the measurement with contacts length-
wise to engine cylinder head.
(6) Compare the crosswise to lengthwise measure-
ments to determine out-of-roundness. If the measure-
ments differ by more than 0.0635 mm (0.0025 in.),
ream the guide bore to accommodate an oversize
valve stem.
(7) Compare the measured valve guide bore diam-
eter with specifications (7.95-7.97 mm or 0.313-0.314
inch). If the measurement differs from specification
by more than 0.076 mm (0.003 inch), ream the guide
bore to accommodate an oversize valve stem.
ALTERNATIVE METHOD:
(1) Use a dial indicator to measure the lateral
movement of the valve stem (stem-to-guide clear-
ance). This must be done with the valve installed in
its guide and just off the valve seat (Fig. 11).
(2) Correct clearance is 0.025-0.0762 mm (0.001-
0.003 inch). If indicated movement exceeds the spec-
ification ream the valve guide to accommodate an
oversize valve stem.
Valve seats must be ground after reaming the
valve guides to ensure that the valve seat is
concentric to the valve guide.
VALVE SPRING TENSION TEST
Use a Universal Valve Spring Tester and a torque
wrench to test each valve spring for the specified ten-
sion value (Fig. 12).
Replace valve springs that are not within specifica-
tions.
INSTALLATION
(1) Thoroughly clean the valve stems and the valve
guide bores.
(2) Lightly lubricate the stem.
(3) Install the valve in the original valve guide
bore.
(4) Install the replacement valve stem oil seals on
the valve stems. If the 0.381 mm (0.015 inch) over-
size valve stems are used, oversize oil seals are re-
quired.
(5) Position the valve spring and retainer on the
engine cylinder head and compress the valve spring
with Valve Spring Compressor Tool MD-998772A.
(6) Install the valve locks and release the tool.
(7) Tap the valve spring from side to side with a
hammer to ensure that the spring is properly seated
Fig. 10 Measurement of Valve Guide Bore Diameter
Fig. 11 Measurement of Lateral Movement Of Valve
Stem
Fig. 12 Valve Spring Tester
J2.5L ENGINE 9 - 29

at the engine cylinder head. Also tap the top of the
retainer to seat the valve locks.
(8) Install the engine cylinder head.
VALVE TIMING
Disconnect the spark plug wires and remove the
spark plugs.
Remove the engine cylinder head cover.
Remove the capscrews, bridge and pivot assembly,
and rocker arms from above the No.1 cylinder.
Alternately loosen each capscrew, one turn at a
time, to avoid damaging the bridge.
Rotate the crankshaft until the No.4 piston is at
top dead center (TDC) on the compression stroke.
Rotate the crankshaft counterclockwise (viewed
from the front of the engine) 90É.
Install a dial indicator on the end of the No.1 cyl-
inder intake valve push rod. Use rubber tubing to se-
cure the indicator stem on the push rod.
Set the dial indicator pointer at zero.
Rotate the crankshaft clockwise (viewed from the
front of the engine) until the dial indicator pointer
indicates 0.305 mm (0.012 inch) travel distance (lift).
The timing notch index on the vibration damper
should be aligned with the TDC mark on the timing
degree scale.
If the timing notch is more than 13 mm (1/2 inch)
away from the TDC mark in either direction, the
valve timing is incorrect.
If the valve timing is incorrect, the cause may be a
broken camshaft pin. It is not necessary to replace
the camshaft because of pin failure. A spring pin is
available for service replacement.
VIBRATION DAMPER
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the serpentine drive belt and fan
shroud.
(3) Remove the vibration damper retaining bolt
and washer.
(4) Use Vibration Damper Removal Tool 7697 to re-
move the damper from the crankshaft (Fig. 1).
INSTALLATION
(1) Apply Mopar Silicone Rubber Adhesive Sealant
to the keyway in the crankshaft and insert the key.
With the key in position, align the keyway on the vi-
bration damper hub with the crankshaft key and tap
the damper onto the crankshaft.
(2) Install the vibration damper retaining bolt and
washer.
(3) Tighten the damper retaining bolt to 108 Nzm
(80 ft. lbs.) torque.
(4) Install the serpentine drive belt and tighten to
the specified tension (refer to Group 7, Cooling Sys-
tems for the proper specifications and procedures).(5) Connect negative cable to battery.
TIMING CASE COVER OIL SEAL REPLACEMENT
This procedure is done with the timing case cover
installed.
(1) Disconnect negative cable from battery.
(2) Remove the serpentine drive belt.
(3) Remove the vibration damper.
(4) Remove the radiator shroud.
(5) Carefully remove the oil seal. Make sure seal
bore is clean.
(6) Position the replacement oil seal on Timing
Case Cover Alignment and Seal Installation Tool
6139 with seal open end facing inward. Apply a light
film of Perfect Seal, or equivalent, on the outside di-
ameter of the seal. Lightly coat the crankshaft with
engine oil.
(7) Position the tool and seal over the end of the
crankshaft and insert a draw screw tool into Seal In-
stallation Tool 6139 (Fig. 3). Tighten the nut against
the tool until it contacts the cover.
(8) Remove the tools. Apply a light film of engine
Fig. 1 Vibration Damper Removal Tool 7697
Fig. 3 Timing Case Cover Oil Seal Installation
9 - 30 2.5L ENGINEJ

oil on the vibration damper hub contact surface of
the seal.
(9) Apply Mopar Silicone Rubber Adhesive Sealant
to the keyway in the crankshaft and insert the key.
With the key inserted in the keyway in the crank-
shaft, install the vibration damper, washer and bolt.
Lubricate and tighten the bolt to 108 Nzm (80 ft. lbs.)
torque.
(10) Install the serpentine belt and tighten to the
specified tension (refer to Group 7, Cooling Systems
for the proper specifications and procedures).
(11) Install the radiator shroud.
(12) Connect negative cable to battery.
TIMING CASE COVER
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the vibration damper (Fig. 4).
(3) Remove the fan and hub assembly and remove
the fan shroud.
(4) Remove the accessory drive brackets that are
attached to the timing case cover.
(5) Remove the A/C compressor (if equipped) and
generator bracket assembly from the engine cylinder
head and move to one side.
(6) Remove the oil pan-to-timing case cover bolts
and timing case cover-to-cylinder block bolts.
(7) Remove the timing case cover and gasket from
the engine.
(8) Pry the crankshaft oil seal from the front of the
timing case cover (Fig. 4).
CLEANING
Clean the timing case cover, oil pan and cylinder
block gasket surfaces.
INSTALLATION
(1) Install a new crankshaft oil seal in the timing
case cover. The open end of the seal should be toward
the inside of the cover. Support the cover at the sealarea while installing the seal. Force it into position
with Seal Installation Tool 6139.
(2) Position the gasket on the cylinder block.
(3) Position the timing case cover on the oil pan
gasket and the cylinder block.
(4) Insert Timing Case Cover Alignment and Seal
Installation Tool 6139 in the crankshaft opening in
the cover (Fig. 5).
(5) Install the timing case cover-to-cylinder block
and the oil pan-to-timing case cover bolts.
(6) Tighten the 1/4 inch cover-to-block bolts to 7
Nzm (60 in. lbs.) torque. Tighten the 5/16 inch front
cover-to-block bolts to 22 Nzm (192 in. lbs.) torque.
Tighten the oil pan-to-cover 1/4 inch bolts to 14 Nzm
(120 in. lbs.) torque. Tighten the oil pan-to-cover 5/16
inch bolts to 18 Nzm (156 in. lbs.) torque.
(7) Remove the cover alignment tool.
(8) Apply a light film of engine oil on the vibration
damper hub contact surface of the seal.
(9) Apply Mopar Silicone Rubber Adhesive Sealant
to the keyway in the crankshaft and insert the key.
With the key inserted in the keyway in the crank-
shaft, install the vibration damper, washer and bolt.
Lubricate and tighten the bolt to 108 Nzm (80 ft. lbs.)
torque.
(10) Install the A/C compressor (if equipped) and
generator bracket assembly.
(11) Install the engine fan and hub assembly and
shroud.
(12) Install the serpentine drive belt and tighten to
obtain the specified tension.
(13) Connect negative cable to battery.
TIMING CHAIN AND SPROCKETS
The timing chain tensioner reduces noise and pro-
longs timing chain life. In addition, it compensates
for slack in a worn or stretched chain and maintains
the correct valve timing.
Fig. 4 Timing Case Cover Components
Fig. 5 Timing Case Cover Alignment and Seal
Installation Tool 6139
J2.5L ENGINE 9 - 31

REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the fan and shroud.
(3) Remove the serpentine drive belt.
(4) Remove the crankshaft vibration damper.
(5) Remove the timing case cover.
(6) Rotate crankshaft until the ``0'' timing mark is
closest to and on the center line with camshaft
sprocket timing mark (Fig. 6).
(7) Remove the oil slinger from the crankshaft.
(8) Remove the camshaft retaining bolt and re-
move the sprockets and chain as an assembly (Fig.
7).
(9) To replace the timing chain tensioner, the oil
pan must be removed.
INSTALLATION
(1) Turn the tensioner lever to the unlocked (down)
position (Fig. 8).(2) Pull the tensioner block toward the ten-
sioner lever to compress the spring. Hold the
block and turn the tensioner lever to the lock
position (Fig. 8).
(3) Apply Mopar Silicone Rubber Adhesive Sealant
to the keyway in the crankshaft and insert the key.
With the key in the crankshaft keyway, install the
crankshaft, camshaft sprockets and timing chain. En-
sure the timing marks on the sprockets are properly
aligned (Fig. 6).
(4) Install the camshaft sprocket retaining bolt and
washer. Tighten the bolt to 108 Nzm (80 ft. lbs.)
torque.
(5) To verify correct installation of the timing
chain, turn the crankshaft to position the camshaft
sprocket timing mark as shown in Fig. 9. Count the
number of chain pins between the timing marks of
both sprockets. There must be 20 pins.
(6) Turn the chain tensioner lever to the unlocked
(down) position (Fig. 8).
(7) Install the oil slinger.
(8) Replace the oil seal in the timing case cover.
(9) Install the timing case cover and gasket.
(10) With the key inserted in the keyway in the
crankshaft, install the vibration damper, washer and
bolt. Lubricate and tighten the bolt to 108 Nzm (80 ft.
lbs.) torque.
(11) Install the fan and shroud.
(12) Connect negative cable to battery.
CAMSHAFT
REMOVAL
WARNING: THE COOLANT IN A RECENTLY OPER-
ATED ENGINE IS HOT AND PRESSURIZED. RE-
LEASE THE PRESSURE BEFORE REMOVING THE
DRAIN COCK, CAP AND DRAIN PLUGS.
(1) Disconnect negative cable from battery.
Fig. 6 CrankshaftÐCamshaft Alignment
Fig. 7 Camshaft and Crankshaft Sprockets and
Chain
Fig. 8 Loading Timing Chain Tensioner
9 - 32 2.5L ENGINEJ

(2) Drain the cooling system. DO NOT waste reus-
able coolant. If the solution is clean, drain it into a
clean container for reuse.
(3) Remove the radiator or radiator and condenser,
if equipped with A/C (refer to Group 7, Cooling Sys-
tem for the proper procedure).
(4) Scribe a mark on the distributor housing in line
with the lip of the rotor.
(5) Scribe a mark on the distributor housing near
the clamp and continue the scribe mark on the cylin-
der block in line with the distributor mark.
(6) For ease of installation, note the position of the
rotor and distributor housing in relation to adjacent
engine components.
(7) Remove the distributor and ignition wires.
(8) Remove the engine cylinder head cover.
(9) Remove the rocker arms, bridges and pivots.
(10) Remove the push rods.
(11) Remove the hydraulic valve tappets from the
engine cylinder head.
(12) Remove the vibration damper.
(13) Remove the timing case cover.
(14) Remove the timing chain and sprockets.
(15) Remove the camshaft (Fig. 10).
INSPECTION
Inspect the cam lobes for wear.
Inspect the bearing journals for uneven wear pat-
tern or finish.
Inspect the bearings for wear.
Inspect the distributor drive gear for wear.
If the camshaft appears to have been rubbing
against the timing case cover, examine the oil pres-
sure relief holes in the rear cam journal. The oil
pressure relief holes must be free of debris.
INSTALLATION
(1) Lubricate the camshaft with Mopar Engine Oil
Supplement, or equivalent.
(2) Carefully install the camshaft to prevent dam-
age to the camshaft bearings (Fig. 10).
(3) Turn the tensioner lever to the unlocked (down)
position (Fig. 8).
(4) Pull the tensioner block toward the ten-
sioner lever to compress the spring. Hold the
block and turn the tensioner lever to the lock
position (Fig. 8).
(5) Install the timing chain, crankshaft sprocket and
camshaft sprocket with the timing marks aligned.
(6) Install the camshaft sprocket retaining bolt and
washer. Tighten the bolt to 108 Nzm (80 ft. lbs.) torque.
(7) Install the timing case cover with a replace-
ment oil seal (Fig. 11). Refer to Timing Case Cover
Installation.
(8) Install the vibration damper.
(9) Install the hydraulic valve tappets.
(10) Install the push rods.
(11) Install the rocker arms, bridges and pivots.
(12) Install the engine cylinder head cover.
(13) Position the oil pump gear. Refer to Distribu-
Fig. 9 Verify SprocketÐChain Installation
Fig. 10 Camshaft
Fig. 11 Timing Case Cover
J2.5L ENGINE 9 - 33

tor in the Component Removal/Installation section of
Group 8D, Ignition Systems.
(14) Install the distributor and ignition wires. Re-
fer to Distributor in the Component Removal/Instal-
lation section of Group 8D, Ignition Systems.
(15) Install the radiator or radiator and condenser,
if equipped with A/C.
(16) Fill the cooling system.
(17) Connect negative cable to battery.
CAMSHAFT PIN REPLACEMENT
REMOVAL
WARNING: DO NOT LOOSEN THE RADIATOR
DRAIN COCK WITH THE SYSTEM HOT AND PRES-
SURIZED BECAUSE SERIOUS BURNS FROM COOL-
ANT CAN OCCUR.
(1) Disconnect negative cable from battery.
(2) Drain the radiator. DO NOT waste reusable
coolant. Drain the coolant into a clean container.
(3) Remove the fan and shroud.
(4) Disconnect the radiator overflow tube, radiator
hoses, automatic transmission fluid cooler pipes (if
equipped).
(5) Remove the radiator.
(6) If equipped with air conditioning:
CAUTION: DO NOT loosen or disconnect any air
conditioner system fittings. Move the condenser
and receiver/drier aside as a complete assembly.
(a) Remove the A/C compressor serpentine drive
belt idler pulley.
(b) Disconnect and remove the generator.
(c) Remove the A/C condenser attaching bolts
and move the condenser and receiver/drier assem-
bly up and out of the way.
(7) Remove the serpentine drive belt.
(8) Remove the crankshaft vibration damper.
(9) Remove the timing case cover. Clean the gasket
material from the cover.
(10) Rotate crankshaft until the crankshaft
sprocket timing mark is closest to and on the center
line with the camshaft sprocket timing mark (Fig.
12).
(11) Remove camshaft sprocket retaining bolt.
(12) Remove the crankshaft oil slinger.
(13) Remove the sprockets and chain as an assem-
bly (Fig. 13).
CAUTION: The following procedural step must be
accomplished to prevent the camshaft from damag-
ing the rear camshaft plug during pin installation.
(14) Inspect the damaged camshaft pin.(15) If the pin is a spring-type pin, remove the bro-
ken pin by inserting a self-tapping screw into the pin
and carefully pulling the pin from the camshaft.
(16) If the pin is a dowel-type pin, center-punch it.
Ensure the exact center is located when center-
punching the pin.
CAUTION: Cover the opened oil pan area to prevent
metal chips from entering the pan.
(17) Drill into the pin center witha4mm(5/32
inch) drill bit.
(18) Insert a self-tapping screw into the drilled pin
and carefully pull the pin from the camshaft.
CAMSHAFT BEARINGS
The camshaft rotates within four steel-shelled, bab-
bitt-lined bearings that are pressed into the cylinder
block and then line reamed. The camshaft bearing
bores and bearing diameters are not the same size.
They are stepped down in 0.254 mm (0.010 inch) in-
crements from the front bearing (largest) to the rear
Fig. 12 Timing Chain Alignment
Fig. 13 Camshaft and Crankshaft Sprocket and
Chain
9 - 34 2.5L ENGINEJ

bearing (smallest). This permits easier removal and
installation of the camshaft. The camshaft bearings
are pressure lubricated.
It is not advisable to attempt to replace cam-
shaft bearings unless special removal and in-
stallation tools are available.
Camshaft end play is maintained by the load
placed on the camshaft by the oil pump and distrib-
utor drive gear. The helical cut of the gear holds the
camshaft sprocket thrust face against the cylinder
block face.
INSTALLATION
(1) Clean the camshaft pin hole.
(2) Compress the center of the replacement spring
pin with vise grips.
(3) Carefully drive the pin into the camshaft pin
hole until it is seated.
(4) Install the camshaft sprocket, crankshaft
sprocket and timing chain with the timing marks
aligned (Fig. 12).
(5) To verify correct installation of the timing
chain, turn the crankshaft to position the camshaft
sprocket timing mark as shown in Fig. 14. Count the
number of chain pins between the timing marks of
both sprockets. There must be 20 pins.
(6) Install the crankshaft oil slinger.
(7) Tighten the camshaft sprocket bolt to 108 Nzm
(80 ft. lbs.) torque.
(8) Check the valve timing.
(9) Coat both sides of the replacement timing case
cover gasket with gasket sealer. Applya3mm(1/8
inch) bead of Mopar Silicone Rubber Adhesive Seal-ant, or equivalent to the joint formed at the timing
case cover and cylinder block.
(10) Position the timing case cover on the oil pan
gasket and the cylinder block.
(11) Place Timing Case Cover Alignment and Seal
Installation Tool 6139 in the crankshaft opening of
the cover (Fig. 15).
(12) Install the timing case cover-to-cylinder block
bolts. Install the oil pan-to-timing case cover bolts.
(13) Tighten the 1/4 inch cover-to-block bolts to 7
Nzm (60 in. lbs.) torque. Tighten the 5/16 inch front
cover-to-block bolts to 22 Nzm (192 in. lbs.) torque.
Tighten the oil pan-to-cover 1/4 inch bolts to 14 Nzm
(120 in. lbs.) torque. Tighten the oil pan-to-cover 5/16
inch bolts to 18 Nzm (156 in. lbs.) torque.
(14) Remove the cover alignment tool and install a
replacement oil seal into the cover.
(15) Install the vibration damper on the crank-
shaft.
(16) Lubricate and tighten the damper bolt to 108
Nzm (80 ft. lbs.) torque.
(17) If equipped with air conditioning:
(a) Install the A/C compressor serpentine drive
belt idler pulley.
(b) Install the generator.
(c) Install the A/C condenser and receiver/drier
assembly.
(18) Install the serpentine drive belt on the pulleys
and tighten (refer to Group 7, Cooling System for the
specifications and procedures).
(19) Install the radiator. Connect the radiator
hoses and automatic transmission fluid cooler pipes,
if equipped. Fill the cooling system.
(20) Install the fan and shroud.
(21) Connect negative cable to battery.
Fig. 14 Verify CrankshaftÐCamshaft Installation
Fig. 15 Timing Case Cover Alignment and Seal
Installation Tool 6139
J2.5L ENGINE 9 - 35

OIL PAN
REMOVAL
(1) Disconnect negative cable from battery.
(2) Raise the vehicle.
(3) Remove the oil pan drain plug and drain the
engine oil.
(4) Disconnect the exhaust pipe at the engine ex-
haust manifold.
(5) Disconnect the exhaust hanger at the catalytic
converter and lower the pipe.
(6) Remove the engine starter motor.
(7) Remove the flywheel/torque converter housing
access cover.
(8) Position a jack stand directly under the engine
vibration damper.
(9) Place a piece of wood (2 x 2) between the jack
stand and the engine vibration damper.
(10) Remove the engine mount through bolts.
(11) Using the jack stand, raise the engine until
adequate clearance is obtained to remove the oil pan.
(12) Remove the oil pan bolts. Carefully remove
the oil pan and gasket.
CLEANING
Clean the block and pan gasket surfaces.
INSTALLATION
(1) Fabricate 4 alignment dowels from 1/4ý11/2
inch bolts. Cut the head off the bolts and cut a slot
into the top of the dowel. This will allow easier in-
stallation and removal with a screwdriver (Fig. 1).
(2) Install two dowels in the timing case cover. Install
the other two dowels in the cylinder block (Fig. 2).
(3) Slide the one-piece gasket over the dowels and
onto the block and timing case cover.
(4) Position the oil pan over the dowels and onto
the gasket.
(5) Install the 1/4 inch oil pan bolts. Tighten these
bolts to 14 Nzm (120 in. lbs.) torque. Install the 5/16
inch oil pan bolts (Fig. 3). Tighten these bolts to 18
Nzm (156 in. lbs.) torque.
(6) Remove the dowels. Install the remaining 1/4
inch oil pan bolts. Tighten these bolts to 14 Nzm (120
in. lbs.) torque.(7) Lower the engine until it is properly located on
the engine mounts.
(8) Install the through bolts and tighten the nuts.
(9) Lower the jack stand and remove the piece of
wood.
(10) Install the flywheel and torque converter
housing access cover.
(11) Install the engine starter motor.
(12) Connect the exhaust pipe to the hanger and to
the engine exhaust manifold.
(13) Install the oil pan drain plug (Fig. 3). Tighten
the plug to 34 Nzm (25 ft. lbs.) torque.
(14) Lower the vehicle.
(15) Connect negative cable to battery.
(16) Fill the oil pan with engine oil to the specified
level.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(17) Start the engine and inspect for leaks.
Fig. 1 Fabrication of Alignment Dowels
Fig. 2 Position of Dowels in Cylinder Block
Fig. 3 Position of 5/16 inch Oil Pan Bolts
9 - 36 2.5L ENGINEJ