Jeep XJ. Manual — part 289
NOTE: When replacing inserts, the odd size inserts
must be either all on the top (in cylinder block) or
all on the bottom (in main bearing cap).
Once the bearings have been properly fitted, pro-
ceed to Crankshaft Main Bearing—Installation.
BEARING-TO-JOURNAL CLEARANCE (CRANKSHAFT
INSTALLED)
When using Plastigage, check only one bearing
clearance at a time.
Install the grooved main bearings into the cylinder
block and the non-grooved bearings into the bearing caps.
Install the crankshaft into the upper bearings dry.
Place a strip of Plastigage across full width of the
crankshaft journal to be checked.
Install the bearing cap and tighten the bolts to 108
N·m (80 ft. lbs.) torque.
NOTE: DO NOT rotate the crankshaft. This will
cause the Plastigage to shift, resulting in an inaccu-
rate reading. Plastigage must not be permitted to
crumble. If brittle, obtain fresh stock.
Remove the bearing cap. Determine the amount of
clearance by measuring the width of the compressed
Plastigage with the scale on the Plastigage envelope
(Fig. 35). Refer to Engine Specifications for the
proper clearance.
Plastigage should indicate the same clearance
across the entire width of the insert. If clearance var-
ies, it may indicate a tapered journal or foreign
material trapped behind the insert.
If the specified clearance is indicated and there are
no abnormal wear patterns, replacement of the bear-
ing inserts is not necessary. Remove the Plastigage
from the crankshaft journal and bearing insert. Pro-
ceed to Crankshaft Main Bearing—Installation.
If the clearance exceeds specification, install a pair of
0.025 mm (0.001 inch) undersize bearing inserts and mea-
sure the clearance as described in the previous steps.
The clearance indicated with the 0.025 mm (0.001
inch) undersize insert pair installed will determine if
this insert size or some other combination will provide
the specified clearance. FOR EXAMPLE: If the clear-
ance was 0.0762 mm (0.003 inch) originally, a pair of
0.0254 mm (0.001 inch) undersize inserts would
reduce the clearance by 0.0254 mm (0.001 inch). The
clearance would then be 0.0508 mm (0.002 inch) and
within the specification. A 0.051 mm (0.002 inch)
undersize bearing insert and a 0.0254 mm (0.001
inch) undersize insert would reduce the original
clearance an additional 0.0127 mm (0.0005 inch). The
clearance would then be 0.0381 mm (0.0015 inch).
CAUTION: Never use a pair of inserts that differ
more than one bearing size as a pair.
FOR EXAMPLE: DO NOT use a standard size
upper insert and a 0.051 mm (0.002 inch) undersize
lower insert.
If the clearance exceeds specification using a pair
of 0.051 mm (0.002 inch) undersize bearing inserts,
measure
crankshaft
journal
diameter
with
a
micrometer. If the journal diameter is correct, the
crankshaft bore in the cylinder block may be mis-
aligned, which requires cylinder block replacement or
machining to true bore.
If journals 1 through 5 diameters are less than
63.4517 mm (2.4981 inches), replace crankshaft or
grind crankshaft down to accept the appropriate
undersize bearing inserts.
Once the proper clearances have been obtained,
proceed to Crankshaft Main Bearing—Installation.
MAIN BEARING JOURNAL DIAMETER
(CRANKSHAFT REMOVED)
Remove the crankshaft from the cylinder block
(refer to Cylinder Block - Disassemble).
Clean the oil off the main bearing journal.
Determine the maximum diameter of the journal
with a micrometer. Measure at two locations 90°
apart at each end of the journal.
The maximum allowable taper and out of round is
0.013 mm (0.0005 inch). Compare the measured
diameter with the journal diameter specification
(Main Bearing Fitting Chart). Select inserts required
to obtain the specified bearing-to-journal clearance.
Once the proper clearances have been obtained,
proceed to Crankshaft Main Bearing—Installation.
Fig. 35 Measuring Bearing Clearance with
Plastigage
1 – PLASTIGAGE SCALE
2 – COMPRESSED PLASTIGAGE
9 - 24
2.5L ENGINE
XJ
SERVICE PROCEDURES (Continued)
MAIN BEARING FITTING CHART
CRANKSHAFT JOURNALS
CORRESPONDING CRANKSHAFT BEARING INSERT
Color Code
Diameter
Upper Insert Size
Lower Insert Size
Yellow
63.5025 - 63.4898 mm
Yellow - Standard
Yellow - Standard
(2.5001 - 2.4996 in.)
Orange
63.4898 - 63.4771mm
Yellow - Standard
Blue- Undersize 0.025 mm
(0.001 in.)
(2.4996 - 2.4991 in.)
0.0127 mm (0.0005 in.)
Undersize
Blue
63.4771 - 63.4644 mm
Blue- Undersize 0.025 mm
(0.001 in.)
Blue- Undersize 0.025 mm
(0.001 in.)
(2.4991 - 2.4986 in.)
0.0254 mm (0.001 in.)
Undersize
Green
63.4644 - 63.4517 mm
Blue - Undersize
0.025 mm (0.001 in.)
Green - Undersize 0.051 mm
(0.002 in.)
(2.4986 - 2.4981 in.)
0.0381 mm (0.0015 in.)
Undersize
Red
63.2485 - 63.2358 mm
Red - Undersize 0.254 mm
(0.010 in.)
Red - Undersize 0.254 mm
(0.010 in.)
(2.4901 - 2.4896 in.)
0.254 mm (0.010 in.)
Undersize
FORM-IN-PLACE GASKETS
There are several places where form-in-place gas-
kets are used on the engine. DO NOT use form-in-
place gasket material unless specified. Care
must be taken when applying form-in-place gaskets.
Bead size, continuity and location are of great impor-
tance. Too thin a bead can result in leakage while too
much can result in spill-over. A continuous bead of
the proper width is essential to obtain a leak-free
joint.
Two types of form-in-place gasket materials are
used in the engine area (Mopar Silicone Rubber
Adhesive Sealant and Mopar Gasket Maker). Each
have different properties and cannot be used inter-
changeably.
MOPAR SILICONE RUBBER ADHESIVE SEALANT
Mopar Silicone Rubber Adhesive Sealant, normally
black in color, is available in 3 ounce tubes. Moisture
in the air causes the sealant material to cure. This
material is normally used on flexible metal flanges.
It has a shelf life of a year and will not properly cure
if over aged. Always inspect the package for the expi-
ration date before use.
MOPAR GASKET MAKER
Mopar Gasket Maker, normally red in color, is
available in 6 cc tubes. This anaerobic type gasket
material cures in the absence of air when squeezed
between smooth machined metallic surfaces. It will
not cure if left in the uncovered tube. DO NOT use
on flexible metal flanges.
SURFACE PREPARATION
Parts assembled with form-in-place gaskets may be
disassembled
without
unusual
effort.
In
some
instances, it may be necessary to lightly tap the part
with a mallet or other suitable tool to break the seal
between the mating surfaces. A flat gasket scraper
may also be lightly tapped into the joint but care
must be taken not to damage the mating surfaces.
Scrape or wire brush all gasket surfaces to remove
all loose material. Inspect stamped parts to ensure
gasket rails are flat. Flatten rails with a hammer on
a flat plate, if required. Gasket surfaces must be free
of oil and dirt. Make sure the old gasket material is
removed from blind attaching holes.
GASKET APPLICATION
Assembling parts using a form-in-place gasket
requires care.
XJ
2.5L ENGINE
9 - 25
SERVICE PROCEDURES (Continued)
Mopar Silicone Rubber Adhesive Sealant should be
applied in a continuous bead approximately 3 mm
(0.12 inch) in diameter. All mounting holes must be
circled. For corner sealing, a 3 or 6 mm (1/8 or 1/4
inch) drop is placed in the center of the gasket con-
tact area. Uncured sealant may be removed with a
shop towel. Components should be torqued in place
while the sealant is still wet to the touch (within 10
minutes). The use of a locating dowel is recom-
mended during assembly to prevent smearing the
material off location.
Mopar Gasket Maker should be applied sparingly
to one gasket surface. The sealant diameter should
be 1.00 mm (0.04 inch) or less. Be certain the mate-
rial surrounds each mounting hole. Excess material
can easily be wiped off. Components should be
torqued in place within 15 minutes. The use of a
locating dowel is recommended during assembly to
prevent smearing the material off location.
ENGINE PERFORMANCE
It is important that the vehicle is operating to its
optimum performance level to maintain fuel economy
and the lowest emission levels. If vehicle is not oper-
ating to these standards, refer to Engine Diagnosis
outlined in this section. The following procedures can
assist in achieving the proper engine diagnosis.
(1) Test cranking amperage draw. Refer to Electri-
cal Group 8B, Cold Cranking Test.
(2) Check intake manifold bolt torque; Refer to
Group 11, Exhaust System and Intake Manifold.
(3) Perform cylinder compression test. Refer to
Cylinder Compression Pressure Test in the Engine
Diagnosis area of this section.
(4) Clean or replace spark plugs as necessary and
adjust gap as specified in Electrical Group 8D.
Tighten to specifications.
(5) Test resistance of spark plug cables. Refer to
Electrical Group 8D, Spark Plug Cables.
(6) Inspect the primary wires. Test coil output volt-
age and primary resistance. Replace parts as neces-
sary. Refer to Electrical Group 8D, for specifications.
(7) Test fuel pump for pressure. Refer to Group 14,
Fuel System Specifications.
(8) The air filter elements should be replaced as
specified in Lubrication and Maintenance, Group 0.
(9) Inspect crankcase ventilation system as out
lined in Group 0, Lubrication and Maintenance. For
emission controls see Group 25, Emission Controls
for service procedures.
(10) Road test vehicle as a final test.
HONING CYLINDER BORES
Before honing, stuff plenty of clean shop towels
under the bores and over the crankshaft to keep
abrasive materials from entering the crankshaft
area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823 equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round as well as removing light
scuffing, scoring or scratches. Usually a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). 20-60 strokes,
depending on the bore condition, will be sufficient to
provide a satisfactory surface. Using honing oil
C-3501-3880 or a light honing oil available from
major oil distributors.
CAUTION: DO NOT use engine or transmission oil,
mineral spirits or kerosene.
(3) Honing should be done by moving the hone up
and down fast enough to get a crosshatch pattern.
The hone marks should INTERSECT at 50° to 60°
for proper seating of rings (Fig. 36).
(4) A controlled hone motor speed between 200 and
300 RPM is necessary to obtain the proper cross-
hatch angle. The number of up and down strokes per
minute can be regulated to get the desired 50° to 60°
angle. Faster up and down strokes increase the cross-
hatch angle.
(5) After honing, it is necessary that the block be
cleaned to remove all traces of abrasive. Use a brush
Fig. 36 Cylinder Bore Crosshatch Pattern
1 – CROSSHATCH PATTERN
2 – INTERSECT ANGLE
9 - 26
2.5L ENGINE
XJ
SERVICE PROCEDURES (Continued)
to wash parts with a solution of hot water and deter-
gent. Dry parts thoroughly. Use a clean, white, lint-
free cloth to check that the bore is clean. Oil the
bores after cleaning to prevent rusting.
REPAIR DAMAGED OR WORN THREADS
CAUTION: Be sure that the tapped holes maintain
the original center line.
Damaged or worn threads can be repaired. Essen-
tially, this repair consists of:
• Drilling out worn or damaged threads.
• Tapping the hole with a special Heli-Coil Tap, or
equivalent.
• Installing an insert into the tapped hole to bring
the hole back to its original thread size.
SERVICE ENGINE ASSEMBLY (SHORT BLOCK)
A service replacement engine assembly (short
block) may be installed whenever the original cylin-
der block is defective or damaged beyond repair. It
consists of the cylinder block, crankshaft, piston and
rod assemblies. If needed, the camshaft must be pro-
cured separately and installed before the engine is
installed in the vehicle.
A short block is identified with the letter “S”
stamped on the same machined surface where the
build date code is stamped for complete engine
assemblies.
Installation includes the transfer of components
from the defective or damaged original engine. Fol-
low the appropriate procedures for cleaning, inspec-
tion and torque tightening.
HYDROSTATIC LOCK
When an engine is suspected of hydrostatic lock
(regardless of what caused the problem), follow the
steps below.
(1) Perform the Fuel Pressure Release Procedure
(refer to Group 14, Fuel System).
(2) Disconnect the negative cable from the battery.
(3) Inspect
air
cleaner,
induction
system
and
intake manifold to ensure system is dry and clear of
foreign material.
(4) Place a shop towel around the spark plugs to
catch any fluid that may possibly be under pressure
in the cylinder head. Remove the plugs from the
engine.
CAUTION: DO NOT use the starter motor to rotate
the crankshaft. Severe damage could occur.
(5) With all spark plugs removed, rotate the crank-
shaft using a breaker bar and socket.
(6) Identify the fluid in the cylinders (i.e. coolant,
fuel, oil, etc.).
(7) Make sure all fluid has been removed from the
cylinders.
(8) Repair engine or components as necessary to
prevent this problem from occurring again.
(9) Squirt engine oil into the cylinders to lubricate
the walls. This will prevent damage on restart.
(10) Install new spark plugs. Tighten the spark
plugs to 37 N·m (27 ft. lbs.) torque.
(11) Drain engine oil. Remove and discard the oil
filter.
(12) Install the drain plug. Tighten the plug to 34
N·m (25 ft. lbs.) torque.
(13) Install a new oil filter.
(14) Fill
engine
crankcase
with
the
specified
amount and grade of oil (refer to Group 0, Lubrica-
tion and Maintenance).
(15) Connect the negative cable to the battery.
(16) Start the engine and check for any leaks.
ENGINE OIL SERVICE
WARNING: NEW OR USED ENGINE OIL CAN BE
IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED BY
INTERNAL COMBUSTION, CAN BE HAZARDOUS TO
YOUR HEALTH. THOROUGHLY WASH EXPOSED
SKIN WITH SOAP AND WATER. DO NOT WASH
SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR
SOLVENTS, HEALTH PROBLEMS CAN RESULT. DO
NOT POLLUTE, DISPOSE OF USED ENGINE OIL
PROPERLY.
ENGINE OIL SPECIFICATION
CAUTION: Do not use non-detergent or straight
mineral oil when adding or changing crankcase
lubricant. Engine failure can result.
API SERVICE GRADE CERTIFIED
In gasoline engines. use an engine oil that is API
Service Grade Certified (Fig. 37).
Standard engine oil identification notations have
been adopted to aid in the proper selection of engine
oil. The identifying notations are located on the label
of engine oil plastic bottles and the top of engine oil
cans (Fig. 37).
SAE VISCOSITY
An SAE viscosity grade is used to specify the vis-
cosity of engine oil. SAE 10W-30 specifies a multiple
viscosity engine oil.
When choosing an engine oil, consider the range of
temperatures the vehicle will be operated in before
the next oil change. Select an engine oil that is best
XJ
2.5L ENGINE
9 - 27
SERVICE PROCEDURES (Continued)
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