Jeep J-10 Series 1982 Technical & Service Manual page 165

(8) If oil clearance exceeds specification, install pair
of 0.001-inch (0.025 mm) undersize bearing inserts and
measure clearance as described in steps (3) through (6)
above.
(9) Clearance measured with 0.001-inch (0.025 mm)
undersize inserts installed will determine if pair of
0.001-inch (0.025 mm) undersize inserts or some other
size combination will provide correct clearance. For ex
ample, if clearance was 0.0035-inch (0.089 mm) origi
nally, a pair of 0.001-inch (0.025 mm) undersize inserts
will reduce clearance by 0.001 inch (0.025 mm). Oil clear
ance will be 0.0025 inch (0.064 mm) and within specifica
tion. Combination of 0.002-inch (0.051 mm) undersize
insert and 0.001-inch (0.025 mm) undersize insert will
reduce this clearance additional 0.0005 inch (0.013 mm)
and oil clearance will be 0.002 inch (0.051 mm).
CAUTION: Never use a combination of inserts that
have a difference of more than one bearing size. For
example, do not use a standard upper and 0.002-inch
(0.051 mm) undersize lower insert.
(10) If oil clearance exceeds specification with pair of
0.002-inch (0.051 mm) undersize inserts, measure crank
shaft journal diameter with micrometer. Refer to Speci
fications. If journal diameter is correct, crankshaft bore
in cylinder block may be misaligned, which requires
cylinder block replacement. If journal diameter is in
correct, replace or grind crankshaft to standard
undersize.
Installation
(1) Lubricate journal contact surface of each insert
with clean engine oil.
(2) Loosen all main bearing caps.
(3) Install main bearing upper insert(s).
(4) Install main bearing cap(s) and lower insert(s).
Tighten retaining screws evenly with 100 foot-pounds
(136 N*m) torque in steps of 30, 60, 90 and 100 foot
pounds (41, 81, 122 and 136 N»m) torque. Rotate crank
shaft after each tightening step to determine if it rotates
freely. If it does not rotate freely, examine inserts for
proper installation and size.
(5) Install oil pan using replacement gaskets and
seals. Tighten drain plug securely.
(6) Fill crankcase to specified level with clean lube
oil.
Measuring Main Bearing Journals with Micrometer (Crankshaft
Removed)
(1) Wipe main bearing journals clean.
(2) Measure each journal diameter with microme
ter. Note difference between maximum and minimum
diameters of each journal.
(3) Refer to Specifications for maximum allowable
taper and out-of-roundness.
ENGINES 1B-97
(4) Compare measured largest diameter dimensions
with journal diameter dimensions listed in Main Bear
ing Fitting Chart.
(5) Select insert pairs that will provide specified
bearing clearance. Correct clearance is 0.0015 to 0.0020
inch (0.038 to 0.051 mm) for No. 1 through No. 4 main
bearings and 0.0025 to 0.0030 inch (0.064 to 0.076 mm)
for rear main bearing.
Rear Main Bearing Oil Seal
The rear main bearing oil seal consists of a two-piece
neoprene single lip seal. Correct installation of the seal
is required for leak-free engine operation.
Removal
(1) Drain engine oil.
(2) Remove starter motor.
(3) Remove oil pan.
(4) Remove oil pan front and rear neoprene oil
seals.
(5) Remove oil pan side gaskets.
(6) Thoroughly clean gasket mating surfaces of oil
pan and engine block. Remove all sludge and residue
from oil pan sump.
(7) Remove rear main bearing cap.
(8) Remove and discard lower seal.
NOTE: To ensure leak-free operation, always replace
the upper and lower seal halves as a pair.
(9) Clean main bearing cap thoroughly to remove
all sealer.
(10) Loosen all remaining main bearing capscrews.
(11) Use brass drift and hammer to tap upper seal
half until sufficient portion of seal is protruding to per
mit pulling seal out completely.
Installation
(1) Wipe crankshaft seal surface area clean and ap
ply light film of oil.
(2) Coat block contact surface area of replacement
upper seal half with soap and lip of seal with clean
engine oil (fig. 1B-150).
(3) Insert upper seal half into engine block.
NOTE: The lip of the seal must face the front of the
engine.
(4) Coat both sides of replacement lower seal half
end tabs with Jeep Gasket-in-a-Tube (RTV silicone), or
equivalent. Do not apply sealer to lip of seal.
(5) Coat outer curved surface of lower seal half with
soap and lip of seal with clean engine oil.
(6) Insert seal into cap recess and seat firmly.
(7) Apply Jeep Gasket-in-a-Tube (RTV silicone), or
equivalent, to both chamfered edges of rear main bear
ing cap.