Measuring Bearing Clearance With Plastigage (Crankshaft Installed); Removing No. 4 Main Bearing Insert; Normal Main Bearing Wear Pattern - Jeep J-10 Series 1982 Technical & Service Manual

P
ENGINES 1B-59
T-Z
Crankshaft Connecting Rod Journal 7
Color Code and Diameter in
Inches (Journal Size)
Bearing Insert Color Code
Upper Insert Size
Lower Insert Size
Yellow - 2.4995 to 2.4990 (Standard)
(63.4873 to 63.4746 mm)
Yellow
Yellow
— Standard
Yellow — Standard
Orange
- 2.4990 to 2.4985 (0.0005 Undersize)
(63.4746 to 63.4619 mm)
- Standard Black
- 0.001-inch Undersize (0.025mm)
Black
- 2.4985 to 2.4980 (0.001 Undersize)
(63.4619 to 63.4492 mm)
Black - 0.001-inch Undersize (0.025mm) Black - 0.001 -inch Undersize (0.025mm)
Green - 2.4980 to 2.4975 (0.0015 Undersize)
(63.4492 to 63.4365 mm)
Black - 0.001-inch Undersize (0.025mm) Green - 0.002-inch Undersize (0.051mm)
Red
- 2.4895 to 2.4890 (0.010 Undersize)
(63.2333 to 63.2206 mm)
Red
- 0.010-inch Undersize (0.254mm)
Red
- 0.010-inch Undersize (0.254mm)
NOTE: Because there is no hole in the number 4 main
journal, use a tongue depressor or similar soft-faced tool
to remove the bearing (fig. lB-93). After movjng the
insert approximately one inch (254 mm), the insert can
be removed by applying pressure wider the tab.
Fig. 1B-93 Removing No. 4 Main Bearing Insert
(7) In the same manner described above, remove
remaining bearings one at a time for inspection.
Inspection
(1) Wipe lower insert clean and inspect for abnor
mal wear pattern and for metal or other foreign mate
rial imbedded in lining. Normal main bearing wear
pattern is illustrated in figure 1B-94.
NOTE: If the crankshaft journal is scored, remove the
engine for crankshaft repair.
(2) Inspect back of insert for fractures, scrapings or
irregular wear pattern.
UPPER
LOWER
HEAVIER WEAR
PATTERN ON
LOWER INSERT
60262C
NO WEAR IN
THIS AREA
LOW AREA
IN BEARING
60762
Fig. 1B-94 Normal Main Bearing Wear Pattern
(3) Inspect locking tabs for damage.
(4) Replace bearing inserts that are damaged or
worn.
Measuring Bearing Clearance with Plastigage (Crankshaft Installed)
NOTE: Measure clearance ofone bearing at a time. All
other bearings must remain tightened.
(1) Remove main bearing cap and insert.
(2) Clean insert and exposed portion of crankshaft
journal.
(3) Place strip of Plastigage across full width of
bearing insert.
(4) Install bearing cap and tighten bolts with 80
foot-pounds (108 N«m) torque.
(5) Remove bearing cap and determine amount of
clearance by measuring width of compressed Plastigage
with scale on Plastigage envelope (fig. 1B-95). Correct
clearance is 0.001 to 0.003 inch (0.025 to 0.076 mm). The
Plastigage should maintain same size across entire
width of insert. If size varies, it may indicate tapered
journal or foreign material trapped behind insert.