Jeep J-10 Series 1982 Technical & Service Manual page 163

(5) If end play is not within specification, inspect
crankshaft thrust faces for wear. If no wear is apparent,
replace No. 3 (thrust) main bearing inserts and measure
end play. If end play is not within specification, replace
crankshaft.
NOTE: When installing the No. 3 (thrust) main bearing
inserts, pry the crankshaft fore and aft to align the
thrust faces of the bearing inserts before final
tightening.
Crankshaft Main Bearings
The main bearing inserts are steel-backed aluminum-
tin lined. Optional bearing inserts are available with
overplated copper-lead linings. The main bearing caps
are numbered 1 through 5, front to rear, with an arrow
to indicate the forward position. The upper main bear
ing insert surfaces are grooved. The lower insert sur
faces are smooth.
Each bearing insert pair is selectively fitted to its
respective journal to obtain the desired operating oil
clearance. In production, the select fit is obtained by
using various-sized color-coded main bearing inserts as
listed in the Main Bearing Fitting Chart. The bearing
color code appears on the edge of the insert.
NOTE: The bearing size is not stamped on production
inserts.
The main bearing journal diameter is identified in
production by a color-coded paint mark on the adjacent
cheek toward the flanged (rear) end of the crankshaft,
except for the rear main journal. The paint mark that
identifies the rear main journal diameter is on the
crankshaft rear flange.
Refer to the Main Bearing Fitting Chart to select the
proper bearing inserts to obtain the specified bearing
clearance. The correct clearance is 0.0015 to 0.0020 inch
(0.038 to 0.051 mm) for No. 1 through No. 4 main bear
ings and 0.0025 to 0.0030 inch (0.064 to 0.076 mm) for the
rear main bearing.
ENGINES iB-95
When required, use different sized upper and lower
bearing inserts as a pair. Use a standard size upper
insert in combination with a 0.001-inch (0.025 mm) un
dersize lower insert to reduce the clearance by 0.0005
inch or 1/2 thousandth of an inch (0.013 mm).
Example:
Insert
Incorrect
Correct
Upper
Standard Standard
Lower
0.002-inch (0.051 mm)
undersize
0.001 -inch (0.025 mm)
undersize
70242
NOTE: When installing upper and lower inserts having
different sizes, install undersize inserts either all on the
top (upper) or all on the bottom (lower). Never use bear
ing inserts in combination with greater than 0.001-inch
(0.025 mm) difference in size.
Service replacement main bearing inserts are avail
able as pairs in the following sizes: standard, 0.001-inch
(0.025 mm) undersize, 0.002-inch (0.051 mm) undersize,
0.010-inch (0.254 mm) undersize, and 0.012-inch (0.305
mm) undersize. The bearing size is stamped on the back
of service replacement inserts.
NOTE: The 0.012-inch (0.305 mm) undersize insert is
not used for production engine assembly.
Removal
The following procedure can be used when the engine
is installed in the vehicle.
(1) Drain engine oil and remove oil pan.
(2) Remove main bearing cap and lower insert.
(3) Remove lower insert from bearing cap.
(4) Remove upper insert by loosening all other bear
ing caps and inserting tool fabricated from cotter pin
approximately 1/2-inch (14 mm) into crankshaft oil
hole. Fabricate cotter pin as depicted in figure 1B-147.
Main Bearing Fitting Chart
Crankshaft Main Bearing Journal
Color Code and Diameter in
Bearing Color Code
Inches (mm)
Upper Insert Size Lower Insert Size
Yellow -2.7489 to 2.7484
(69.8220-69.8O93mm) (Standard)
Yellow —Standard
Yellow —Standard
Orange
-2.7484 to 2.7479
(69.8093-69.7966mm)(0.0005 Undersize)
Yellow —Standard
Black
0.001-inch (0.025mm) Undersize
Black -2.7479 to 2.7474
(69.7966-69.7839mm)(0.001 Undersize)
Black
0.001 -inch (0.025mm) Undersize
Black
0.001-inch(0.025mm) Undersize
Green
-2.7474 to 2,7469
(69.7839-69.7712mm)(0.0015 Undersize)
Black
0.001 -inch (0.025mm) Undersize
Green
0.002-inch(0.051mm) Undersize
Red —2.7389 to 2.7384
(69.568O69.5553mm)(0.010 Undersize)
Red
0.010-inch (0.254mm) Undersize
Red
0.010-inch(0.254mm) Undersize
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