pistons JEEP LIBERTY 2002 KJ / 1.G User Guide

FLEX PLATE
REMOVAL
(1) Remove the transmission.
(2) Remove the bolts and flexplate.
INSTALLATION
(1) Position the flexplate onto the crankshaft and
install the bolts hand tight.
(2) Tighten the flexplate retaining bolts to 95 N´m
(70 ft. lbs.) in the sequence shown (Fig. 51).
(3) Install the transmission.
PISTON & CONNECTING ROD
DESCRIPTION
CAUTION: Do not use a metal stamp to mark con-
necting rods as damage may result, instead use ink
or a scratch awl.
The pistons are made of a high strength aluminum
alloy. The top ring groove is coated with a anti-seize
coating. The connecting rods are made of forged pow-
dered metal, with a ªfractured capº design. A full
floating piston pin is used to attach the piston to the
connecting rod (Fig. 52).
1 Connecting Rod
2 Piston
3 Piston Pin
4 Oil Slinger Slot
STANDARD PROCEDURE
CONNECTING ROD BEARING - FITTING
Inspect the connecting rod bearings for scoring and
bent alignment tabs. Check the bearings for normal
wear patterns, scoring, grooving, fatigue and pitting.
Replace any bearing that shows abnormal wear.
Inspect the connecting rod journals for signs of
scoring, nicks and burrs.
Misaligned or bent connecting rods can cause
abnormal wear on pistons, piston rings, cylinder
walls, connecting rod bearings and crankshaft con-
necting rod journals. If wear patterns or damage to
any of these components indicate the probability of a
misaligned connecting rod, inspect it for correct rod
alignment. Replace misaligned, bent or twisted con-
necting rods.
(1) Wipe the oil from the connecting rod journal.
(2) Lubricate the upper bearing insert and install
in connecting rod.
(3) Use piston ring compressor and Guide Pins
Special Tool 8507 to install the rod and piston assem-
blies. The oil slinger slots in the rods must face front
of the engine. The ªFº's near the piston wrist pin
bore should point to the front of the engine.
(4) Install the lower bearing insert in the bearing
cap. The lower insert must be dry. Place strip of Plas-
tigage across full width of the lower insert at the cen-
ter of bearing cap. Plastigage must not crumble in
use. If brittle, obtain fresh stock.
(5) Install bearing cap and connecting rod on the
journal and tighten bolts to 27 N´m (20 ft. lbs.) plus a
Fig. 51 Flexplate Tightening Sequence
1 - FLEXPLATE
Fig. 52 PISTON AND ROD ASSEMBLY
KJENGINE - 3.7L 9 - 49

90É turn. DO NOT rotate crankshaft. Plastigage will
smear, resulting in inaccurate indication.
(6) Remove the bearing cap and determine amount
of bearing-to-journal clearance by measuring the
width of compressed Plastigage. Refer to Engine
Specifications for the proper clearance.Plastigage
should indicate the same clearance across the
entire width of the insert. If the clearance var-
ies, it may be caused by either a tapered jour-
nal, bent connecting rod or foreign material
trapped between the insert and cap or rod.
(7) If the correct clearance is indicated, replace-
ment of the bearing inserts is not necessary. Remove
the Plastigage from crankshaft journal and bearing
insert. Proceed with installation.
(8) If bearing-to-journal clearance exceeds the
specification, determin which services bearing set to
use the bearing sizes are as follows:
Bearing
MarkSIZE USED WITH
JOURNAL SIZE
.025 US.025 mm 57.871-57.879 mm
(.001 in.) (2.2783-2.2786 in.)
Std.STANDARD 57.896-57.904 mm
(2.2793-2.2810 in.)
.250 US.250 mm 57.646-57.654 mm
(.010 in.) (2.2695-2.2698 in.)
(9) Repeat the Plastigage measurement to verify
your bearing selection prior to final assembly.
(10) Once you have selected the proper insert,
install the insert and cap. Tighten the connecting rod
bolts to 27 N´m (20 ft. lbs.) plus a 90É turn.
Slide snug-fitting feeler gauge between the con-
necting rod and crankshaft journal flange. Refer to
Engine Specifications for the proper clearance.
Replace the connecting rod if the side clearance is
not within specification.
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 micrometer.
(2) Measure the inside diameter of the cylinder
bore at a point 38.0 mm (1.5 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. 54).
(3) The coated pistons will be serviced with the
piston pin and connecting rod pre-assembled.(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. 53). 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.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the following components:
²Oil pan and gasket/windage tray (Refer to 9 -
ENGINE/LUBRICATION/OIL PAN - REMOVAL).
²Cylinder head covers (Refer to 9 - ENGINE/
CYLINDER HEAD/CYLINDER HEAD COVER(S) -
REMOVAL) and (Refer to 9 - ENGINE/CYLINDER
HEAD/CYLINDER HEAD COVER(S) - REMOVAL).
²Timing chain cover (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT / CHAIN COVER(S)
- REMOVAL).
²Cylinder head(s) (Refer to 9 - ENGINE/CYLIN-
DER HEAD - REMOVAL) and (Refer to 9 - ENGINE/
CYLINDER HEAD - REMOVAL).
(3) If necessary, remove top ridge of cylinder bores
with a reliable ridge reamer before removing pistons
from cylinder block.Be sure to keep tops of pis-
tons covered during this operation.Pistons and
connecting rods must be removed from top of cylinder
block. When removing piston and connecting rod
Fig. 53 Moly Coated Piston - Typical
1 - MOLY COATED
2 - MOLY COATED
9 - 50 ENGINE - 3.7LKJ
PISTON & CONNECTING ROD (Continued)

assemblies from the engine, rotate crankshaft so the
each connecting rod is centered in cylinder bore.
CAUTION: DO NOT use a number stamp or a punch
to mark connecting rods or caps, as damage to
connecting rods could occur
NOTE: Connecting rods and bearing caps are not
interchangeable and should be marked before
removing to ensure correct reassembly.
(4) Mark connecting rod and bearing cap positions
using a permanent ink marker or scribe tool.
CAUTION: Care must be taken not to damage the
fractured rod and cap joint face surfaces, as engine
damage may occur.
(5) Remove connecting rod cap. Install Special Tool
8507 Connecting Rod Guides into the connecting rod
being removed. Remove piston from cylinder bore.
Repeat this procedure for each piston being removed.
CAUTION: Care must be taken not to nick crank-
shaft journals, as engine damage may occur
(6) Immediately after piston and connecting rod
removal, install bearing cap on the mating connect-
ing rod to prevent damage to the fractured cap and
rod surfaces.
CLEANING
CAUTION: DO NOT use a wire wheel or other abra-
sive cleaning devise to clean the pistons or con-
necting rods. The pistons have a Moly coating, this
coating must not be damaged.
(1) Using a suitable cleaning solvent clean the pis-
tons in warm water and towel dry.
(2) Use a wood or plastic scraper to clean the ring
land grooves.
CAUTION: DO NOT remove the piston pin from the
piston and connecting rod assembly.
INSPECTION
Check the connecting rod journal for excessive
wear, taper and scoring (Refer to 9 - ENGINE/EN-
GINE BLOCK/CONNECTING ROD BEARINGS -
STANDARD PROCEDURE).
Check the connecting rod for signs of twist or bend-
ing.
Check the piston for taper and elliptical shape
before it is fitted into the cylinder bore (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON & CONNECT-
ING ROD - STANDARD PROCEDURE).
Check the piston for scoring, or scraping marks in
the piston skirts. Check the ring lands for cracks
and/or deterioration.
INSTALLATION
(1) Before installing piston and connecting rod
assemblies into the bore, install the piston rings.
(2) Immerse the piston head and rings in clean
engine oil. Position a ring compressor over the piston
and rings. Tighten ring compressor.Ensure posi-
tion of rings do not change during this opera-
tion.
(3) Position bearing onto connecting rod. Ensure
that tabs in bearing shell aligns with slots in con-
necting rod. Verify that parting line of bearing is
aligned with parting line of connecting rod.
(4) Lubricate bearing surface with clean engine oil.
(5) Install Special Tool 8507 Connecting Rod
Guides into connecting rod bolt threads (Fig. 55).
(6) The pistons are marked on the piston pin bore
surface with an raised ªFº indicating installation
position. This mark must be pointing toward the
front of engine on both cylinder banks. The connect-
ing rod oil slinger slot faces the front of the engine
(Fig. 56).
(7) Wipe cylinder bore clean and lubricate with
engine oil.
(8) Rotate crankshaft until connecting rod journal
is on the center of cylinder bore. Insert rod and pis-
Fig. 54 Bore Gauge - Typical
1 - FRONT
2 - BORE GAUGE
3 - CYLINDER BORE
4 - 38 MM (1.5 in)
KJENGINE - 3.7L 9 - 51
PISTON & CONNECTING ROD (Continued)

(1) Inspect air cleaner, induction system and
intake manifold to insure system is dry and clear of
foreign material.
(2) Remove negative battery cable.
(3) Place a shop towel around the spark plugs
when removing them from the engine. This will catch
any fluid that may possibly be in the cylinder under
pressure.
(4) With all spark plugs removed, rotate engine
crankshaft using a breaker bar and socket.
(5) Identify the fluid in the cylinder(s) (i.e., cool-
ant, fuel, oil or other).
(6) Make sure all fluid has been removed from the
cylinders. Inspect engine for damage (i.e., connecting
rods, pistons, valves, etc.)
(7) Repair engine or components as necessary to
prevent this problem from re-occurring.
CAUTION: Squirt approximately one teaspoon of oil
into the cylinders, rotate engine to lubricate the cyl-
inder walls to prevent damage on restart.
(8) Install new spark plugs.
(9) Drain engine oil and remove oil filter.
(10) Install a new oil filter.
(11) Fill engine with specified amount of approved
oil.
(12) Connect negative battery cable.
(13) Start engine and check for any leaks.
STANDARD PROCEDURE - FORM-IN-PLACE
GASKETS AND SEALERS
There are numerous places where form-in-place
gaskets are used on the engine. Care must be taken
when applying form-in-place gaskets to assure
obtaining the desired results.Do not use form-in-
place gasket material unless specified.Bead size,
continuity, and location are of great importance. Too
thin a bead can result in leakage while too much can
result in spill-over which can break off and obstruct
fluid feed lines. A continuous bead of the proper
width is essential to obtain a leak-free gasket.
There are numerous types of form-in-place gasket
materials that are used in the engine area. Mopart
Engine RTV GEN II, MopartATF-RTV, and Mopart
Gasket Maker gasket materials, each have different
properties and can not be used in place of the other.
MOPARtENGINE RTV GEN IIis used to seal
components exposed to engine oil. This material is a
specially designed black silicone rubber RTV that
retains adhesion and sealing properties when
exposed to engine oil. Moisture in the air causes the
material to cure. This material is available in three
ounce tubes and has a shelf life of one year. After one
year this material will not properly cure. Alwaysinspect the package for the expiration date before
use.
MOPARtATF RTVis a specifically designed
black silicone rubber RTV that retains adhesion and
sealing properties to seal components exposed to
automatic transmission fluid, engine coolants, and
moisture. This material is available in three ounce
tubes and has a shelf life of one year. After one year
this material will not properly cure. Always inspect
the package for the expiration date before use.
MOPARtGASKET MAKERis an anaerobic type
gasket material. The material cures in the absence of
air when squeezed between two metallic surfaces. It
will not cure if left in the uncovered tube. The
anaerobic material is for use between two machined
surfaces. Do not use on flexible metal flanges.
MOPARtBED PLATE SEALANTis a unique
(green-in-color) anaerobic type gasket material that
is specially made to seal the area between the bed-
plate and cylinder block without disturbing the bear-
ing clearance or alignment of these components. The
material cures slowly in the absence of air when
torqued between two metallic surfaces, and will rap-
idly cure when heat is applied.
MOPARtGASKET SEALANTis a slow drying,
permanently soft sealer. This material is recom-
mended for sealing threaded fittings and gaskets
against leakage of oil and coolant. Can be used on
threaded and machined parts under all tempera-
tures. This material is used on engines with multi-
layer steel (MLS) cylinder head gaskets. This
material also will prevent corrosion. MopartGasket
Sealant is available in a 13 oz. aerosol can or 4oz./16
oz. can w/applicator.
SEALER APPLICATION
MopartGasket Maker material should be applied
sparingly 1 mm (0.040 in.) diameter or less of sealant
to one gasket surface. Be certain the material sur-
rounds each mounting hole. Excess material can eas-
ily be wiped off. Components should be torqued in
place within 15 minutes. The use of a locating dowel
is recommended during assembly to prevent smear-
ing material off the location.
MopartEngine RTV GEN II or ATF RTV gasket
material should be applied in a continuous bead
approximately 3 mm (0.120 in.) in diameter. All
mounting holes must be circled. For corner sealing, a
3.17 or 6.35 mm (1/8 or 1/4 in.) drop is placed in the
center of the gasket contact 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 usage of a
locating dowel is recommended during assembly to
prevent smearing material off the location.
9s - 10 ENGINEKJ
ENGINE - 2.4L (Continued)

(8) Install the starter.
(9) Connect the crankshaft position sensor.
(10) Install the engine block heater power cable, if
equipped.
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
(11) Install the structural cover.
(12) Install the exhaust pipe.
(13) Connect the oxygen sensors.
(14) Lower vehicle.
(15) Connect the knock sensors.
(16) Connect the engine to body ground straps.
(17) Install the power brake booster vacuum hose.
(18) Install the breather hoses.
(19) Install the PCV hose.
(20) Install the fuel rail.
(21) Install the coil over plugs.
(22) Reconnect the engine wiring harness at the
following points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(23) Connect lower radiator hose.
(24) Connect upper radiator hose.
(25) Connect throttle and speed control cables.
(26) Install the heater hose assembly.
(27) Install coolant recovery bottle.
(28) Install the power steering pump.
(29) Install the generator.
(30) Install the A/C compressor.
(31) Install the drive belt.
(32) Install the fan shroud with the electric fan
assembly.
(33) Install the radiator core support bracket.
(34) Install the air cleaner assembly.
(35) Refill the engine cooling system.
(36) Install the hood.
(37) Check and fill engine oil.
(38) Connect the battery negative cable.
(39) Start the engine and check for leaks.SPECIFICATIONS
SPECIFICATIONS - 2.4L ENGINE
DESCRIPTION SPECIFICATION
General Specification
Type In-Line OHV, DOHC
Number of Cylinders 4
Displacement 2.4 Liters
(148 cu. in.)
Bore 87.5 mm
(3.445 in.)
Stroke 101.0 mm
(3.976 in.)
Compression Ratio 9.4:1
Firing Order 1-3-4-2
Compression Pressure 690 kPa (Minimum)
(100 psi Minimum)
Max. Variation Between
Cylinders25%
Cylinder Block
Cylinder Bore Diameter 87.4924±87.5076 mm
(3.4446±3.4452 in.)
Out-of-Round (Max.) 0.051 mm
(0.002 in.)
Taper (Max.) 0.051 mm
(0.002 in.)
Pistons
Piston Diameter 87.463±87.481 mm
(3.4434±3.4441 in.)
Clearance @ 14 mm
(9/16 in.) from bottom of
skirt0.024±0.057 mm
(0.0009±0.0022 in.)
Weight 346±356 grams
(12.20±12.56 oz.)
Land Clearance
(Diametrical)0.614±0.664 mm
(0.024±0.026 in.)
Piston Length 66.25 mm
(2.608 in.)
Piston Ring Groove
Depth No. 14.640±4.784 mm
(0.182±0.188 in.)
Piston Ring Groove
Depth No. 24.575±4.719 mm
(0.180±0.185 in.)
KJENGINE9s-13
ENGINE - 2.4L (Continued)

AIR CLEANER ELEMENT
REMOVAL - 2.4L
Housing removal is not necessary for element (fil-
ter) replacement.
(1) Disconnect air intake duct at side of element
cover.
(2) Pry up 2 spring clips from front of housing
cover (spring clips retain cover to housing).
(3) Release housing cover from locating tabs
located on rear of housing, and remove cover.
(4) Remove air cleaner element (filter) from hous-
ing.
(5) Clean inside of housing before replacing ele-
ment.
INSTALLATION - 2.4L
(1) Install element into housing.
(2) Position housing cover into housing locating
tabs.
(3) Pry up spring clips and lock cover to housing.
(4) Connect air intake duct.
If any air filter, air resonator, air intake tubes or
air filter housing clamps had been loosened or
removed, tighten them to 5 N´m (40 in. lbs.) torque.
CYLINDER HEAD
DESCRIPTION
The cross flow designed, aluminum cylinder head
contains dual over-head camshafts with four valves
per cylinder (Fig. 5). The valves are arrange in two
in-line banks. The intake valves face toward the left
side of the vehicle. The exhaust valves face the right
side. The cylinder head incorporates powdered metalvalve guides and seats. The cylinder head is sealed to
the block using a multi-layer steel head gasket and
retaining bolts.
Integral oil galleries providing lubrication passages
to the hydraulic lash adjusters, camshafts, and valve
mechanisms.
OPERATION
The cylinder head closes the combustion chamber,
allowing the pistons to compress the fuel/air mixture
for ignition. The valves are actuated by the lobe pro-
files on the camshaft to open and close at specified
duration to either allow clean air in the combustion
chamber or the exhaust gases out; depending on the
stroke of the engine.
DIAGNOSIS AND TESTING - CYLINDER HEAD
GASKET
A cylinder head gasket leak can be located between
adjacent cylinders or between a cylinder and the
adjacent water jacket.
Possible indications of the cylinder head gasket
leaking between adjacent cylinders are:
²Loss of engine power
²Engine misfiring
²Poor fuel economy
Combustion Leak Tester C-3685-A
Cylinder Compression Pressure Adaptor 8116
Fig. 5 Cylinder Head and Camshafts
CAM PLUG - NOT SHOWN
1 - CAMSHAFT BEARING CAPS
2 - PLUG
3 - CAMSHAFT
4 - CYLINDER HEAD
5 - CAMSHAFT OIL SEAL
KJENGINE9s-19
ENGINE - 2.4L (Continued)

INSPECTION
(1) Inspect camshaft bearing journals for damage
and binding (Fig. 19). If journals are binding, check
the cylinder head for damage. Also check cylinder
head oil holes for clogging.
(2) Check the cam lobe and bearing surfaces for
abnormal wear and damage. Replace camshaft if
defective.
NOTE: If camshaft is replaced due to lobe wear or
damage, always replace the rocker arms.
(3) Measure the lobe actual wear (unworn area -
wear zone = actual wear) (Fig. 19) and replace cam-
shaft if out of limit. Standard value is 0.0254 mm
(0.001 in.), wearlimitis 0.254 mm (0.010 in.).
INSTALLATION
CAUTION: Ensure that NONE of the pistons are at
top dead center when installing the camshafts.
(1) Lubricate all camshaft bearing journals, rocker
arms and camshaft lobes.
(2) Install all rocker arms in original positions, if
reused.
(3) Position camshafts on cylinder head bearing
journals. Install right and left camshaft bearing caps
No.2±5andright No. 6. Tighten M6 fasteners to 12
N´m (105 in. lbs.) in sequence shown in (Fig. 20).
(4) Apply MopartGasket Maker to No. 1 and No.
6 bearing caps (Fig. 21). Install bearing caps and
tighten M8 fasteners to 28 N´m (250 in. lbs.).NOTE: Bearing end caps must be installed before
seals can be installed.
(5) Install camshaft oil seals. (Refer to 9 -
ENGINE/CYLINDER HEAD/CAMSHAFT OIL
SEAL(S) - INSTALLATION)
(6) Install camshaft target magnet and camshaft
position sensor.
(7) Install cylinder head cover. (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION)
(8) Install timing belt rear cover and camshaft
sprocket. (Refer to 9 - ENGINE/VALVE TIMING/
TIMING BELT / CHAIN COVER(S) - INSTALLA-
TION)
(9) Install timing belt. (Refer to 9 - ENGINE/
VALVE TIMING/TIMING BELT/CHAIN AND
SPROCKETS - INSTALLATION)
Fig. 19 Checking Camshaft(s) for Wear
1 - UNWORN AREA
2 - ACTUAL WEAR
3 - BEARING JOURNAL
4 - LOBE
5 - WEAR ZONE
Fig. 20 Camshaft Bearing Cap Tightening Sequence
Fig. 21 Camshaft Bearing Cap Sealing
1 - 1.5 mm (.060 in.) DIAMETER BEAD OF MOPAR GASKET
MAKER
KJENGINE9s-25
CAMSHAFT(S) (Continued)

shown in (Fig. 34). Refer to for Engine Specifications
(Refer to 9 - ENGINE - SPECIFICATIONS). Correct
piston to bore clearance must be established in order
to assure quiet and economical operation.
NOTE: Pistons and cylinder bores should be mea-
sured at normal room temperature, 21ÉC (70ÉF).
STANDARD PROCEDURE - CYLINDER BORE
HONING
(1) Used carefully, the cylinder bore resizing hone,
recommended tool C-823 or equivalent, equipped
with 220 grit stones, is the best tool for this honing
procedure. 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.
(2) Deglazing of the cylinder walls may be done
using a cylinder surfacing hone, recommended toolC-3501 or equivalent, equipped with 280 grit stones,
if the cylinder bore is straight and round. 20±60
strokes depending on the bore condition, will be suf-
ficient to provide a satisfactory surface. Use a light
honing oil.Do not use engine or transmission oil,
mineral spirits or kerosene.Inspect cylinder walls
after each 20 strokes.
(3) Honing should be done by moving the hone up
and down fast enough to get a cross-hatch pattern.
When hone marksintersectat 40-60 degrees, the
cross hatch angle is most satisfactory for proper seat-
ing of rings (Fig. 36).
(4) A controlled hone motor speed between
200±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 40±60
degree angle. Faster up and down strokes increase
the cross-hatch angle.
(5) After honing, it is necessary that the block be
cleaned again to remove all traces of abrasive.
CAUTION: Ensure all abrasives are removed from
engine parts after honing. It is recommended that a
solution of soap and hot water be used with a
brush and the parts then thoroughly dried. The bore
can be considered clean when it can be wiped
clean with a white cloth and cloth remains clean.
Oil the bores after cleaning to prevent rusting.
CLEANING
Clean cylinder block thoroughly using a suitable
cleaning solvent.
Fig. 34 Checking Cylinder Bore -Typical
Fig. 35 Piston Measurement - Typical
Fig. 36 Cylinder Bore Cross-Hatch Pattern
1 - CROSS-HATCH PATTERN
2 - 40ɱ60É
KJENGINE9s-31
ENGINE BLOCK (Continued)

INSPECTION
ENGINE BLOCK
(1) Clean cylinder block thoroughly and check all
core hole plugs for evidence of leaking.
(2) If new core plugs are to be installed, (Refer to 9
- ENGINE - STANDARD PROCEDURE - ENGINE
CORE AND OIL GALLERY PLUGS).
(3) Examine block and cylinder bores for cracks or
fractures.
(4) Check block deck surfaces for flatness. Deck
surface must be within service limit of 0.1 mm (0.004
in.).
CYLINDER BORE
NOTE: The cylinder bores should be measured at
normal room temperature, 21ÉC (70ÉF).
The cylinder walls should be checked for out-of-
round and taper with Tool C119 or equivalent (Fig.
37) (Refer to 9 - ENGINE - SPECIFICATIONS). If
the cylinder walls are badly scuffed or scored, the
cylinder block should be replaced, and new pistons
and rings fitted.
Measure the cylinder bore at three levels in direc-
tions A and B (Fig. 37). Top measurement should be
10 mm (3/8 in.) down and bottom measurement
should be 10 mm (3/8 in.) up from bottom of bore.
(Refer to 9 - ENGINE - SPECIFICATIONS).
CONNECTING ROD BEARINGS
STANDARD PROCEDURE
CONNECTING ROD - FITTING
(1) For measuring connecting rod bearing clear-
ance procedure and use of Plastigage(Refer to 9 -
ENGINE - STANDARD PROCEDURE). For bearing
clearance refer to Engine Specifications. (Refer to 9 -
ENGINE - SPECIFICATIONS)
NOTE: The rod bearing bolts should not be reused.
(2) Before installing theNEWbolts the threads
should be oiled with clean engine oil.
(3) Install each bolt finger tight then alternately
torque each bolt to assemble the cap properly.
(4) Tighten the bolts to 27 N´m PLUS 1/4 turn (20
ft. lbs. PLUS 1/4 turn)Do not use a torque
wrench for last step.
(5) Using a feeler gauge, check connecting rod side
clearance (Fig. 38). Refer to clearance specifications
(Refer to 9 - ENGINE - SPECIFICATIONS).
CRANKSHAFT
DESCRIPTION
The crankshaft is made of nodular cast iron and
includes five main bearing journals and four connect-
ing rod journals (Fig. 39). The number three journal
is the location for the thrust bearing. The mains and
connecting rod journals have undercut fillet radiuses
that are rolled for added strength. To optimize bear-
ing loading, eight counterweights are used.
Fig. 37 Checking Cylinder Bore Size
Fig. 38 Connecting Rod Side Clearance
9s - 32 ENGINEKJ
ENGINE BLOCK (Continued)

(4) Install flex plate. Apply MopartLock & Seal
Adhesive to bolt threads and tighten bolts to 95 N´m
(70 ft. lbs.).
(5) Install the transmission.
PISTON & CONNECTING ROD
DESCRIPTION
The pistons are made of a cast aluminum alloy.
The pistons have pressed-in pins attached to forged
powdered metal connecting rods. The pistons pin is
offset 1 mm (0.0394 in.) towards the thrust side of
the piston. The connecting rods are a cracked cap
design and are not repairable. Hex head cap screws
are used to provide alignment and durability in the
assembly. The pistons and connecting rods are ser-
viced as an assembly.
OPERATION
The piston and connecting rod is the link between
the combustion force to the crankshaft.
REMOVAL
NOTE: Cylinder Head must be removed before Pis-
tons and Rods. Refer to Cylinder Head Removal in
this section.
(1) Remove top ridge of cylinder bores with a reli-
able ridge reamer before removing pistons from cyl-
inder block.Be sure to keep tops of pistons
covered during this operation. Mark piston with
matching cylinder number (Fig. 60).
(2) Remove oil pan. Scribe the cylinder number on
the side of the rod and cap (Fig. 61) for identification.
(3) Pistons have a directional stamping in the
front half of the piston facing towards thefrontof
engine.
(4) Pistons and connecting rods must be removed
from top of cylinder block. Rotate crankshaft so that
each connecting rod is centered in cylinder bore.
(5) Remove Balance Shaft Assembly. Refer to Bal-
ance Shaft Removal in this section.
(6) Remove connecting rod cap bolts. Push each
piston and rod assembly out of cylinder bore.
NOTE: Be careful not to nick crankshaft journals.
(7) After removal, install bearing cap on the mat-
ing rod.
(8) Piston and Rods are serviced as an assembly.
Fig. 59 Rear Crankshaft SealÐInstallation
1 - SPECIAL TOOL 6926±2 INSTALLER
Fig. 60 Piston Markings
1 - DIRECTIONAL ARROW WILL BE IMPRINTED IN THIS AREA
9s - 40 ENGINEKJ
CRANKSHAFT OIL SEAL - REAR (Continued)