Jeep Wrangler 1999 Electronic Service Manual page 675

9 - 20 2.5L ENGINE
SERVICE PROCEDURES (Continued)
FITTING CONNECTING ROD BEARINGS
INSPECTION
BEARINGS
Inspect the connecting rod bearings for scoring and
bent alignment tabs (Fig. 13) (Fig. 14). Check the
bearings for normal wear patterns, scoring, grooving,
fatigue and pitting (Fig. 15). Replace any bearing
that shows abnormal wear.
Inspect the connecting rod journals for signs of
scoring, nicks and burrs.
Fig. 13 Connecting Rod Bearing Inspection
Fig. 14 Locking Tab Inspection
CONNECTING RODS
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.
Fig. 15 Scoring Caused by Insufficient Lubrication
or by Damaged Crankshaft Pin Journal
BEARING-TO-JOURNAL CLEARANCE
(1) Wipe the oil from the connecting rod journal.
(2) Use short rubber hose sections over rod bolts
during installation.
(3) Lubricate the upper bearing insert and install
in connecting rod.
(4) Use piston ring compressor to install the rod
and piston assemblies. The oil squirt holes in the
rods must face the camshaft. The arrow on the piston
crown should point to the front of the engine (Fig.
16). Verify that the oil squirt holes in the rods face
the camshaft and that the arrows on the pistons face
the front of the engine.
Fig. 16 Rod and Piston Assembly Installation
(5) 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.
(6) Install bearing cap and connecting rod on the
journal and tighten nuts to 45 N·m (33 ft. lbs.)
torque. DO NOT rotate crankshaft. Plastigage will
smear, resulting in inaccurate indication.
(7) Remove the bearing cap and determine amount
of bearing-to-journal clearance by measuring the
width of compressed Plastigage (Fig. 17). Refer to
Engine Specifications for the proper clearance. Plas-
tigage should indicate the same clearance
across the entire width of the insert. If the
clearance varies, it may be caused by either a
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