Figure 36. Main bearings and crankshaft, removed and installation.
bearing. Dress all edges of the stock
b. Disassembly. Refer to figure 37, and dis-
carefully to be sure there are no burrs
a s s e m b l e the main bearings and crankshaft.
to mark the bearing. The thickness
Note. Remove the bearing sleeves (2, 4, 6, and 8)
of the feeler stock should be equiva-
from the bearing caps and the engine block.
lent to the maximum clearance, which
i s 0.003 inch, in the hearing. Place
111. Main Bearings and Crankshaft
the feeler stock on a film of oil in the
Cleaning, Inspection, and Repair
b e a r i n g , install the bearing cap, and
a. Cleaning.
torque the capscrews to specified
amount ( in, capscrews, 85-90 ft-
( 1 ) C l e a n all parts in an approved clean-
lb; 9/16 in. capscrews, 100-110 ft.-lb).
ing solvent.
A definite drag should be felt when
( 2 ) C l e a n all oil passages in the crank-
t h e crankshaft is turned.
shaft.
Note. If a new shaft and new bearing
Caution: Use extreme care in clean-
are installed, the crankshaft would be im-
ing and handling the bearing caps,
possible to turn except with a wrench or bar.
sleeves and crankshaft journal to
( 3 ) Inspect and measure the. connecting
avoid damaging the machined surfaces.
r o d journals in a similar manner as
d e s c r i b e d for the main bearing jour-
b. Inspection and Repair.
nals above. The connecting rod jour-
(1) Inspect the bearings. Replace the
nal diameter should be 3.499 to 3.500
bearing if there is an indication of
inches. When the connecting rod is
wear, flaking out, or scoring. If visual
perfectly free, with the proper clear-
inspection appears satisfactory, meas-
ance it should have 0.008 to 0.012 inch
u r e it for thickness with a microme-
side play. Repair or replace a defec-
ter. The correct thickness is 0.1237 to
t i v e part as required.
0 . 1 2 3 2 inch. Replace a bearing that
( 4 ) The main hearing cap must be torqued
is worn more than 0.0005 inch.
t o the correct tightness, inch cap
(2) Inspect the crankshaft journals for
screw should be from 85 to 95 foot-
wear or scoring. The diameter of the
pounds and the 9/16 inch capscrew
c r a n k s h a f t journals should be 3.749
from 100 to 110 foot-pounds.
to 3.750 inches. The clearance of each
( 5 ) I n s p e c t the rear oil seals for cracks,
bearing should be measured with a
w e a r , or deterioration. Replace gas-
piece of feeler stock inch wide and
kets and defective seals.
1/8 inch shorter than the length of the
AGO 8498A
80
