1995 JEEP CHEROKEE engine

INSPECTIONÐCYLINDER BORE
(1) It is mandatory to use a dial bore gauge to
measure each cylinder bore diameter (Fig. 12). To
correctly select the proper size piston, a cylinder bore
gauge, Special Tool 6879, capable of reading in .00019INCREMENTS 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 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 readings.
(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 di-
ameter 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 con-
dition exceeds these maximum limits, the cylinder
must be bored and then honed to accept an oversize
piston. A slight amount of taper always exists in the
cylinder bore after the engine has been in use for a
period of time.
HONINGÐCYLINDER BORE
The honing operation should be closely coordinated
with the fitting of pistons and rings. This will ensure
specified clearances are maintained.
Refer to Standard Service Procedures in the begin-
ning of this Group for the proper honing of cylinder
bores.
Fig. 9 Oil Filter Adaptor Hole
Fig. 10 Front Oil Galley Hole
Fig. 11 Rear Oil Galley Hole
Fig. 12 Cylinder Bore Measurement
9 - 50 2.5L ENGINEJ

ASSEMBLY
Refer to the applicable sections for detailed instruc-
tions.
(1) Install the crankshaft.
(2) Install the connecting rods and the pistons
through the top of the cylinder bores.
(3) Install the front and rear oil galley plugs.
(4) Install the timing chain tensioner.
(5) Install the camshaft.
(6) Install the sprockets and chain as an assembly.
(7) Install the oil slinger to the crankshaft.
(8) Install the timing chain bumper.
(9) Install the timing case cover seal.
(10) Install the timing case cover.(11) Install the oil pan gasket and oil pan.
(12) Install the vibration damper.
(13) Install the water pump. Tighten the mounting
bolts to 31 Nzm (270 in. lbs.) torque.
(14) Remove the distributor from the cylinder
block.
(15) Lubricate the oil filter seal with clean engine
oil. Tighten oil filter to 18 Nzm (13 ft. lbs.) torque.
(16) Install the engine into the vehicle.
(17) Fill the engine with clean lubrication oil (refer
to Group 0, Lubrication and Maintenance).
(18) Fill the cooling system (refer to Group 7, Cool-
ing System for the proper procedures).
J2.5L ENGINE 9 - 51

SPECIFICATIONS
ENGINE SPECIFICATIONS
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ENGINE SPECIFICATIONS (CONT.)
J2.5L ENGINE 9 - 53

ENGINE SPECIFICATIONS (CONT.)
TORQUE SPECIFICATIONS
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4.0L ENGINE SERVICE PROCEDURES
INDEX
page page
Camshaft............................... 74
Camshaft Pin Replacement.................. 75
Engine AssemblyÐXJ Vehicles............... 59
Engine AssemblyÐYJ Vehicles............... 62
Engine Cylinder Head...................... 67
Engine Cylinder Head Cover................. 64
Engine MountÐRear....................... 57
Engine MountsÐFront..................... 56
General Information....................... 55
Hydraulic Tappets......................... 66
OilPan ................................. 77Rocker Arms and Push Rods................ 65
Timing Case Cover........................ 72
Timing Case Cover Oil Seal Replacement....... 73
Timing Chain and Sprockets................. 73
Valve Component ReplaceÐCylinder Head Not
Removed.............................. 65
Valve Stem Seal and Spring Replacement....... 65
Valve Timing............................. 71
Valves and Valve Springs................... 69
Vibration Damper......................... 72
GENERAL INFORMATION
The 4.0 Liter (242 CID) six-cylinder engine is an
In-line, lightweight, overhead valve engine (Fig. 1).
This engine is designed for unleaded fuel.
The engine cylinder head has dual quench-type
combustion chambers that create turbulence and fast
burning of the air/fuel mixture. This results in good
fuel economy.
The cylinders are numbered 1 through 6 from front
to rear. The firing order is 1-5-3-6-2-4 (Fig. 2).
The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within seven main bearings. The camshaft rotates
within four bearings.
BUILD DATE CODE
The engine Build Date Code is located on a ma-
chined surface on the right side of the cylinder block
between the No.2 and No.3 cylinders (Fig. 3).
Fig. 1 Engine Description
Fig. 2 Engine Firing Order
Fig. 3 Build Date Code Location
J4.0L ENGINE 9 - 55

The digits of the code identify:
(1) 1st DigitÐThe year (4 = 1994).
(2) 2nd & 3rd DigitsÐThe month (01 - 12).
(3) 4th & 5th DigitsÐThe engine type/fuel system/
compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1
compression ratio engine with a multi-point fuel in-
jection system).
(4) 6th & 7th DigitsÐThe day of engine build (01 -
31).
FOR EXAMPLE:Code * 401MX12 * identifies a
4.0 Liter (242 CID) engine with a multi-point fuel in-
jection system, 8.7:1 compression ratio and built on
January 12, 1994.
OVERSIZE AND UNDERSIZE COMPONENT
CODES
Some engines may be built with oversize or under-
size components such as:
²Oversize cylinder bores.
²Oversize camshaft bearing bores.
²Undersize crankshaft main bearing journals.
²Undersize connecting rod journals.
These engines are identified by a letter code (Fig.
4) stamped on a boss between the ignition coil and
the distributor (Fig. 5).
ENGINE MOUNTSÐFRONT
The front mounts support the engine at each side.
These supports are made of resilient rubber.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Raise the vehicle.
(3) Support the engine.
(4) Remove the nut from the through bolt (Figs. 6
and 7). DO NOT remove the through bolt.
(5) Remove the retaining bolts and nuts from the
support cushions (Figs. 6 and 7).
(6) Remove the through bolt.
(7) Remove the support cushions.
INSTALLATION
(1) If the engine support bracket was removed, po-
sition the bracket onto the block and install the at-
taching bolts (Figs. 6 and 7). Tighten the engine
support bracket bolts:
²XJ VehiclesÐ61 Nzm (45 ft. lbs.) torque.
²YJ VehiclesÐ62 Nzm (46 ft. lbs.) torque.
(2) ON XJ VEHICLES, if the support cushion
bracket was removed, position the bracket onto the
lower front sill (Fig. 8). Install support cushion
bracket bolts and nuts. Tighten the bolts to 54 Nzm
(40 ft. lbs.) torque. Tighten the nuts to 41 Nzm (30 ft.
lbs.) torque.
(3) Place the support cushion into position on the
support cushion bracket (Figs. 6 and 7). Install and
tighten the bolts and nuts:
²XJ VehiclesÐ41 Nzm (30 ft. lbs.) torque.
²YJ VehiclesÐ52 Nzm (38 ft. lbs.) torque.
(4) Install the through bolt and the retaining nut
(Figs. 6 and 7). Tighten the through bolt nut:
²XJ VehiclesÐ65 Nzm (48 ft. lbs.) torque.
²YJ VehiclesÐ69 Nzm (51 ft. lbs.) torque.
Fig. 4 Oversize and Undersize Component Codes
Fig. 5 Oversize and Undersize Component Code
Location
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(5) Remove the engine support.
(6) Lower the vehicle.
(7) Connect negative cable to battery.
ENGINE MOUNTÐREAR
A resilient rubber cushion supports the transmis-
sion at the rear between the transmission extension
housing and the rear support crossmember or skid
plate.
REMOVALÐXJ VEHICLES
(1) Disconnect negative cable from battery.
(2) Raise the vehicle and support the transmission.
(3) Remove the nuts holding the support cushion to
the crossmember (Figs. 9 and 10). Remove the cross-
member.
(4)MANUAL TRANSMISSION (Fig. 9):
(a) Remove the support cushion nuts and remove
the cushion.
(b) Remove the transmission support bracket
bolts and remove the bracket from the transmis-
sion.
(5)AUTOMATIC TRANSMISSION (Fig. 10):
(a) Remove the support cushion bolts and remove
the cushion and the support bracket from the
transmission (4WD) or from the adaptor bracket
(2WD).
Fig. 6 Front MountsÐXJ Vehicles
Fig. 7 Front MountsÐYJ Vehicles
Fig. 8 Support Cushion BracketÐXJ Vehicles
J4.0L ENGINE 9 - 57