2002 JEEP GRAND CHEROKEE Workshop Manual

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Page 1281 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual MAIN BEARING FITTING CHART
Crankshaft Journals #1-6 Corresponding Crankshaft Bearing Insert
Color Code Diameter Upper Insert Size Lower Insert Size
Yellow63.5025 -63.4898 mm
Yellow - Standard Yellow -

Page 1282 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the spark plugs (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/SPARK PLUG -
REMOVAL).
(3) Raise the vehicle.
(4) Remove the oil pan (Refer t

Page 1283 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual INSPECTION
Wipe the inserts clean and inspect for abnormal
wear patterns and for metal or other foreign material
imbedded in the lining. Normal main bearing insert
wear patterns are illustrated (Fig.

INSPECTION
Wipe the inserts clean and inspect for abnormal
wear patterns and for metal or other foreign material
imbedded in the lining. Normal main bearing insert
wear patterns are illustrated (Fig. 47). In general the
lower bearing half will have a heaver wear pattern.
NOTE: If any of the crankshaft journals are scored,
remove the engine for crankshaft repair.
Inspect the back of the inserts for fractures, scrap-
ings or irregular wear patterns.
Inspect the upper insert locking tabs for damage.
Replace all damaged or worn bearing inserts.
INSTALLATION
(1) Lubricate the bearing surface of each insert
with engine oil.
(2) Loosen all the main bearing caps. Install the
main bearing upper inserts.
(3) Install the lower bearing inserts into the main
bearing caps.
(4) On the rear main cap, apply MopartGasket
Maker sealer on both sides of cylinder block as
shown in (Fig. 48). The dab of sealer should be 3 mm
(0.125 in.) in diameter.
(5) Apply MopartGasket Maker on the rear bear-
ing cap. The bead should be 2.3 mm (0.09 in.) in
diameter. DO NOT apply sealer to the lip of the seal.
(6) Install the main bearing cap(s) and lower
insert(s).
(7) Tighten the bolts of caps 1, 2, 4, 5, 6, and 7 to
54 N´m (40 ft. lbs.) torque. Now tighten these bolts to
95 N´m (70 ft. lbs.) torque. Finally, tighten these
bolts to 108 N´m (80 ft. lbs.) torque.(8) Push the crankshaft forward and backward.
Load the crankshaft front or rear and tighten cap
bolt No.3 to 54 N´m (40 ft. lbs.) torque. Then tighten
to 95 N´m (70 ft. lbs.) torque and finally tighten to
108 N´m (80 ft. lbs.) torque.
(9) Rotate the crankshaft after tightening each
main bearing cap to ensure the crankshaft rotates
freely.
(10) Check crankshaft end play. Crankshaft end
play is controlled by the thrust bearing which is
flange and installed at the No.2 main bearing posi-
tion.
(a) Attach a magnetic base dial indicator to the
cylinder block at either the front or rear of the
engine.
(b) Position the dial indicator rod so that it is
parallel to the center line of the crankshaft.
(c) Pry the crankshaft forward, position the dial
indicator to zero.
(d) Pry the crankshaft forward and backward.
Note the dial indicator readings. End play is the
difference between the high and low measurements
(Fig. 49). Correct end play is 0.038-0.165 mm
(0.0015-0.0065 inch). The desired specifications are
0.051-0.064 mm (0.002-0.0025 inch).
Fig. 47 Main Bearing Wear Patterns
1 - UPPER INSERT
2 - NO WEAR IN THIS AREA
3 - LOW AREA IN BEARING LINING
4 - LOWER INSERT
Fig. 48 Location of Sealer
1-DOWEL
2-SEALER LOCATIONS
3-CYLINDER BLOCK
4-HALFWAY BETWEEN
5-REAR FACE OF CYLINDER BLOCK
6-3mm (0.125 in.)
9 - 40 ENGINE - 4.0LWJ
CRANKSHAFT MAIN BEARINGS (Continued)

Page 1284 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual (e) If end play is not within specification, inspect
crankshaft thrust faces for wear. If no wear is
apparent, replace the thrust bearing and measure
end play. If end play is still not within specific

(e) If end play is not within specification, inspect
crankshaft thrust faces for wear. If no wear is
apparent, replace the thrust bearing and measure
end play. If end play is still not within specifica-
tion, replace the crankshaft.
(11) If the crankshaft was removed, install the
crankshaft into the cylinder block.
(12) Install main bearing cap brace tighten nuts to
47 N´m (35 ft. lbs.) torque.
(13) Install oil pump assy. and tighten attaching
bolts to 23 N´m (17 ft. lbs.)
(14) Install the oil pan (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION).
(15) Install the drain plug. Tighten the plug to 34
N´m (25 ft. lbs.) torque.
(16) Lower the vehicle.
(17) Install the spark plugs. Tighten the plugs to
37 N´m (27 ft. lbs.) torque.
(18) Fill the oil pan with engine oil to the full
mark on the dipstick level.
(19) Connect negative cable to battery.
CRANKSHAFT OIL SEAL -
FRONT
REMOVAL
This procedure is done with the timing case cover
installed.
(1) Disconnect negative cable from battery.
(2) Remove the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).(3) Remove the vibration damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(4) Remove the radiator shroud.
(5) Carefully remove the oil seal. Make sure seal
bore is clean.
INSTALLATION
This procedure is done with the timing case cover
installed.
(1) 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
diameter of the seal. Lightly coat the crankshaft with
engine oil.
(2) Position the tool and seal over the end of the
crankshaft and insert a draw screw tool into Seal
Installation Tool 6139 (Fig. 50). Tighten the nut
against the tool until it contacts the cover.
(3) Remove the tools. Apply a light film of engine
oil on the vibration damper hub contact surface of
the seal.
(4) Apply MopartSilicone Rubber Adhesive Seal-
ant to the keyway in the crankshaft and insert the
key. With the key inserted in the keyway in the
crankshaft, install the vibration damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
INSTALLATION).
(5) Install the serpentine belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
(6) Install the radiator shroud.
(7) Connect negative cable to battery.
Fig. 49 Crankshaft End Play Measurement
1 - DIAL INDICATOR
2 - CRANKSHAFT
Fig. 50 Timing Case Cover Oil Seal Installation
1 - SEAL INSTALLATION TOOL
2 - DRAW SCREW TOOL
WJENGINE - 4.0L 9 - 41
CRANKSHAFT MAIN BEARINGS (Continued)

Page 1285 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual CRANKSHAFT OIL SEAL -
REAR
REMOVAL
The crankshaft rear main bearing oil seal consists
of two half pieces of viton with a single lip that effec-
tively seals the rear of the crankshaft. Replace the
upp

CRANKSHAFT OIL SEAL -
REAR
REMOVAL
The crankshaft rear main bearing oil seal consists
of two half pieces of viton with a single lip that effec-
tively seals the rear of the crankshaft. Replace the
upper and lower seal halves as a unit to ensure leak-
free operation.
(1) Remove transmission inspection cover.
(2) Remove oil pan. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL PAN - REMOVAL)
(3) Remove main bearing cap brace.
(4) Remove rear main bearing cap (No.7).
(5) Push upper seal out of the groove. Ensure that
the crankshaft and seal groove are not damaged.
(6) Remove lower half of the seal from the bearing
cap.
INSTALLATION
The crankshaft rear main bearing oil seal consists
of two half pieces of viton with a single lip that effec-
tively seals the rear of the crankshaft. Replace the
upper and lower seal halves as a unit to ensure leak-
free operation.
(1) Wipe the seal surface area of the crankshaft
until it is clean.
(2) Apply a thin coat of engine oil.
(3) Coat lip of the seal with engine oil.
(4) Carefully position the upper seal into the
groove in the cylinder block. The lip of the seal faces
toward the front of the engine.
(5) Apply MopartGasket Maker sealer on both
sides of cylinder block as shown in (Fig. 51). The dab
of sealer should be 3 mm (0.125 in.) in diameter.
(6) Apply MopartGasket Maker on the rear bear-
ing cap (Fig. 51). The bead should be 2.3 mm (0.09
in.) in diameter. DO NOT apply sealer to the lip of
the seal.
(7) Position the lower seal into the bearing cap
recess and seat it firmly. Be sure the seal is flush
with the cylinder block pan rail.
(8) Coat the outer curved surface of the lower seal
with soap and the lip of the seal with engine oil.
(9) Install the rear main bearing cap. DO NOT
strike the cap more than twice for proper engage-
ment.
(10) Tighten all main bearing bolts to 108 N´m (80
ft. lbs.) torque.
(11) Install the main bearing cap brace. Tighten
nuts to 47 N´m (35 ft. lbs.).
(12) Install the oil pan gasket and oil pan (Refer to
9 - ENGINE/LUBRICATION/OIL PAN - INSTALLA-
TION).(13) Apply MopartSilicone Rubber Adhesive Seal-
ant on cylinder block to rear main bearing cap cor-
ners and cylinder block to front cover joints (four
places) (Fig. 52)
(14) Install transmission inspection cover.
Fig. 51 Location of Sealer
1-DOWEL
2-SEALER LOCATIONS
3-CYLINDER BLOCK
4-HALFWAY BETWEEN
5-REAR FACE OF CYLINDER BLOCK
6-3mm (0.125 in.)
Fig. 52 Oil Pan
1 - SEALER LOCATIONS
9 - 42 ENGINE - 4.0LWJ

Page 1286 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual HYDRAULIC LIFTERS
DESCRIPTION
Valve lash is controlled by hydraulic tappets
located inside the cylinder block, in tappet bores
above the camshaft.
REMOVAL
NOTE: Retain all the components in the same o

HYDRAULIC LIFTERS
DESCRIPTION
Valve lash is controlled by hydraulic tappets
located inside the cylinder block, in tappet bores
above the camshaft.
REMOVAL
NOTE: Retain all the components in the same order
as removed.
(1) Remove the engine cylinder head(Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL).
(2) Remove the push rods.
(3) Remove the tappets through the push rod open-
ings in the cylinder block with a Hydraulic Valve
Tappet Removal/Installation Tool (Fig. 53).
CLEANING
Clean each tappet assembly in cleaning solvent to
remove all varnish, gum and sludge deposits.
INSPECTION
Inspect for indications of scuffing on the side and
base of each tappet body.
Inspect each tappet base for concave wear with a
straightedge positioned across the base. If the base is
concave, the corresponding lobe on the camshaft is
also worn. Replace the camshaft and tappets.
After cleaning and inspection, test each tappet for
specified leak-down rate tolerance to ensure zero-lash
operation (Fig. 54).
Swing the weighted arm of the hydraulic valve tap-
pet tester away from the ram of the Leak-Down
Tester.
(1) Place a 7.925-7.950 mm (0.312-0.313 inch)
diameter ball bearing on the plunger cap of the tap-
pet.(2) Lift the ram and position the tappet (with the
ball bearing) inside the tester cup.
(3) Lower the ram, then adjust the nose of the ram
until it contacts the ball bearing. DO NOT tighten
the hex nut on the ram.
(4) Fill the tester cup with hydraulic valve tappet
test oil until the tappet is completely submerged.
(5) Swing the weighted arm onto the push rod and
pump the tappet plunger up and down to remove air.
When the air bubbles cease, swing the weighted arm
away and allow the plunger to rise to the normal
position.
(6) Adjust the nose of the ram to align the pointer
with the SET mark on the scale of the tester and
tighten the hex nut.
(7) Slowly swing the weighted arm onto the push
rod.
(8) Rotate the cup by turning the handle at the
base of the tester clockwise one revolution every 2
seconds.
(9) Observe the leak-down time interval from the
instant the pointer aligns with the START mark on
the scale until the pointer aligns with the 0.125
mark. A normally functioning tappet will require
20-110 seconds to leak-down. Discard tappets with
leak-down time interval not within this specification.
INSTALLATION
Retain all the components in the same order as
removed.
Fig. 53 HYDRAULIC VALVE TAPPET REMOVAL -
4.0L
1 - HYDRAULIC TAPPET REMOVAL TOOL
2 - CYLINDER BLOCK
Fig. 54 Leak-Down Tester
1 - POINTER
2 - WEIGHTED ARM
3 - RAM
4 - CUP
5 - HANDLE
6 - PUSH ROD
WJENGINE - 4.0L 9 - 43

Page 1287 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual It is not necessary to charge the tappets with
engine oil. They will charge themselves within a very
short period of engine operation.
(1) Dip each tappet in MopartEngine Oil Supple-
ment, or equivale

It is not necessary to charge the tappets with
engine oil. They will charge themselves within a very
short period of engine operation.
(1) Dip each tappet in MopartEngine Oil Supple-
ment, or equivalent.
(2) Use Hydraulic Valve Tappet Removal/Installa-
tion Tool to install each tappet in the same bore from
where it was originally removed.
(3) Install the cylinder head (Refer to 9 - ENGINE/
CYLINDER HEAD - INSTALLATION).
(4) Install the push rods in their original locations.
(5) Install the rocker arms and bridge and pivot
assemblies at their original locations. Loosely install
the capscrews at each bridge.
(6) Tighten the capscrews alternately, one turn at
a time, to avoid damaging the bridges. Tighten the
capscrews to 28 N´m (21 ft. lbs.) torque.
(7)
Pour the remaining MopartEngine Oil Supple-
ment, or equivalent over the entire valve actuating
assembly. The MopartEngine Oil Supplement, or equiv-
alent must remain with the engine oil for at least 1 609
km (1,000 miles). The oil supplement need not be
drained until the next scheduled oil change.
(8) Install the cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
PISTON & CONNECTING ROD
DESCRIPTION
The pistons (Fig. 55) are made of a high strength
aluminum alloy, the piston skirts are coated with a
solid lubricant (Molykote) to reduce friction and pro-
vide scuff resistance. The connecting rods are made
of cast iron.
STANDARD PROCEDURE - PISTON 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 microme-
ter.
(2) Measure the inside diameter of the cylinder
bore at a point 49.5 mm (1-15/16 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. 57).
(3) The coated pistons will be serviced with the
piston pin and connecting rod pre-assembled.The
coated piston connecting rod assembly can be
used to service previous built engines and
MUST be replaced as complete sets.Tin coated
pistons should not be used as replacements for coated
pistons.
(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. 56). 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.
(5) Piston installation into the cylinder bore
requires slightly more pressure than that required
for non-coated pistons. The bonded coating on the
piston will give the appearance of a line-to-line fit
with the cylinder bore.
Fig. 55 Piston and Connecting Rod Assembly
Fig. 56 Moly Coated Piston
1 - MOLY COATED
2 - MOLY COATED
9 - 44 ENGINE - 4.0LWJ
HYDRAULIC LIFTERS (Continued)

Page 1288 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual PISTON SIZE CHART
CYLINDER BORE SIZE PISTON LETTER SIZE
98.438 - 98.448 mm
(3.8755 - 3.8759 in.)A
98.448 - 98.458 mm
(3.8759 - 3.8763 in.)B
98.458 - 98.468 mm
(3.8763 - 3.8767 in.)C
98.468 - 98.478 mm

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