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ENGINEG-bCYLINDER
9-49
U P P E R
-
LOWER
'
I
'
Fig. 1 15-Main
Bearing Identification
1361,383
8
4 2 6 Cubic Inch)
edge of the bearing.
On all engines, number 3 bearing halves are
flanged to carry the thrust load and are not inter-
changeable with the other four bearings. Bearings
that are not badly worn or pitted must be reinstalled
in the same position.
The bearing caps are not interchangeable and
should be marked at removal to insure the correct as-
sembly. Bearing shells are available in standard and
the following undersizes: .001, .002, .003, .010 and
.012 inch. Never install an undersize bearing shell
that will reduce the clearance below specifications.
Removal
(1)
Remove the oil pan and mark the bearing caps
before removal.
(2)
Remove the bearing caps one at a time. Re-
move the upper half of the bearing by inserting Tool
CBEARING
1
Fig.116-Removing
or
Installing M a i n Bearing
fled
C-3059)
C-3059 (Fig. 116) into the oil hole
of the crankshaft.
(3) Slowly rotate the crankshaft clockwise, forcing
out the upper half of bearing shell.
Measuring Main Bearing Clearance
(Shim Stock Methodl
(1) Smooth the edges of a
Y 2
X
% inch piece of soft
copper or brass shim stock, .001 inch thickness.
(2)
Lubricate the main bearing journals and posi-
tion the shim stock across the center main journal.
(3) Install the bearing in the center main bearing
cap, bearing tang in groove in cap, lubricate bearing
and seat cap or block. Tighten bolts to
85
foot-
pounds torque.
(4)
If a slight drag is felt as the crankshaft is
turned (move no more than
y4
turn in either direc-
tioh), the clearance is
.001 inch or less and is con-
sidered satisfactory.
If, however, no drag is felt, the bearing is too large
or the crankshaft cannot be rotated, the bearing is
too small and should be replaced with the correct
size.
(5) Measure crankshaft end play to
.002-.007 inch.
If end play is less than .002" or more than .007", in-
stall a new Number 3 main bearing.
(6)
Fit the remaining bearings in same manner.
Only one main bearing should be selectively fitted
while all other main bearing caps are properly
torqued.
It is permissible to use one .001 inch undersize
bearing shell with one standard bearing shell or one
.002 inch bearing shell with one .001 inch undersize
shell.
Always use the smaller diameter bearing half
as the upper.
Never use a new bearing with a used
bearing and never use an upper bearing half more
than .001 inch smaller than the lower bearing half.
Installation
of
the Upper Main Bearing
NOTE:
When installing a new upper bearing shell,
slightly chamfer the sharp edges from the plain
side.
(1)
Start bearing in place, and insert Tool (2-3059
into the oil hole of the crankshaft (Fig. 116).
(2) Slowly rotate the crankshaft counter-clockwise
sliding the bearing into position.
(3) After all bearings have been fitted, tighten all
caps to
85
foot-pounds torque. The crankshaft end
play should be .002 to .007 inch.
REPLACEMENT OF THE REAR MAIN
BEARING OIL SEALS
(Crankshaft
Removed)
Upper Seal
der block
so
that both ends protrude.
(1)
Install a new rear bearing oil seal in the cylin-
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