Measuring Connecting Rod Bearing-To-Journal Clearance With Plastigage - Jeep 1987 Wrangler Workshop Manual

2.5L 1-4 ENGINE OVERHAUL
ENGINE ASSEMBLY
pin is
8 9 0 0 N ( 2 , 0 0 0
pounds) press fitted into
the rod.
A squirt hole in the crankshaft end of the c o n -
necting rod p r o v i d e s lubrication for the
camshaft lobes, distributor drive gear, cylinder
walls and piston pins.
Misaligned or bent connecting rods can c a u s e
abnormal wear on pistons, piston rings, cylin-
der walls, connecting rod bearings and crank-
shaft connecting 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 connecting rods.
Connecting Rod Bearings
The connecting rod bearings are two-piece,
steel-backed, lead-aluminum alloy units.
E a c h bearing insert is selectively fitted to its
respective journal to obtain the specified oper-
ating clearance between the bearing and the
journal. In production, the select fit is obtained
by using various-sized, color-coded bearing in-
serts a s listed in the bearing fitting chart. The
color code appears on the edge of the bearing
insert.
N O T E : T h e size is not stamped on inserts used
for production of engines.
The rod journal is identified during the engine
production by a color-coded paint mark on the
adjacent cheek or counterweight toward the
flanged (rear) end of the crankshaft. The color
codes used to indicate journal sizes are listed in
the bearing fitting chart.
When required, upper and lower bearing inserts
of different sizes may be used a s a pair. A stan-
dard size insert is sometimes used in combina-
tion with a 0.001 inch undersize insert to reduce
clearance 0.0005 inch.
C A U T I O N : Do not intermix bearing c a p s . E a c h
connecting rod and its bearing cap are stamped
with the a s s o c i a t e d cylinder number on a
machined surface adjacent to the oil squirt hole
that faces the camshaft side of the cylinder
block.
Measuring Connecting Rod Bearing-to-Journal
Clearance with Plastigage
Wipe the journal clean of oil.
U s e short rubber hose sections over rod bolts
during installation.
Lubricate the upper bearing insert and install in
connecting rod.
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