(9) Replace remaining bearings in same
e. Inspection and repair of crankshaft.
bearings for excessive wear, scoring, taper, out of
round, and other damages. See tabulated data for
minimum allowances for bearings and journals.
Be sure thrust side of front main
(2) Inspect crankshaft gear for cracks or tooth
bearing lower half is flush with thrust
side of upper half, then check
Replace gear if defective.
crankshaft endplay. Endplay should
(3) When installing new crankshaft, also
be 0.002 to 0.004 inch.
install new main and connecting rod bearings.
f. Installation of crankshaft. Reverse procedure in
(10) Torque numbers I and 4 main bearing
c. above, observing the following:
capscrews to 70 foot pounds, and all others to 60 foot
(1) Time gears.
(2) Torque bearing capscrews .(paragraph 6-
(11) Install oil pan.
81a.(10)) and check bearing clearance.
b. Clearance. The crankshaft bearing clearance
(3) Be sure front main bearing lower half is
should be checked as follows after new bearing halves
flush with upper half on thrust side, then check endplay.
have been installed or when engine performance
(crankshaft knock) indicates need for such a check.
(1) Remove bearing cap and place a piece of
0.002 by 1/2 by I inch shim stock in bearing cap (Figure
Remove engine from the truck
(paragraph 6-74c.). Strip engine down to bare block by
(2) Install bearing. cap and tighten as given in
removing remaining accessories (paragraph 6-74d.),
a.(10) above. If crankshaft rotates with noticeable drag,
clearance is correct.
Remove shim stock and
reassemble bearings to engine.
b. Cleaning, inspection, and repair.
(3) Clearance may be checked by plastiqauge
(1) Remove gasket residue from cylinder
method-if plastigauge and special measuring scale are
available. If this method is used, do not rotate crankshaft
(2) Remove dirt, carbon, and sludge.
with plastigauge in place.
(3) Clean oil and water passages.
crankshaft bearing clearance, if bearing shells are being
(4) Clean block with SD and dry with
reused, is 0.0029 inch.
(5) Inspect block for cracks or damage.
Be sure front main thrust bearing
(6) Inspect expansion plug for good condition
lower half is flush with upper half on
and tight seal, and replace plug if necessary.
thrust side, then check crankshaft
(7) Examine machined surfaces for scratches,
endplay. Endplay should be 0.002 to
nicks, burrs, or similar damage.
(8) Examine all threaded holes and retap any
that are stripped or damaged.
c. Removal of crankshaft.
(9) Inspect cylinder bores while holding a light
(1) Remove the engine (paragraph 6-74c.).
at the bottom of each bore. If rust pits are evident, or if
(2) Remove engine flywheel and bell housing
bores are deeply scratched or scored, rebore block.
(paragraph 6-74d. (5) and (6)) and oil pump.
(10) Rotate dial indicator in cylinder or measure
(3) Remove timing gear cover, cover plate,
bore with inside micrometer, and observe and record
and crankshaft pulley (paragraph 6-74d.(7)).
largest and smallest indications (Figure 6-39). The
(4) Remove the pistons from the engine block
difference between the indications is the amount of out of
round. Move dial
(5) Mark and remove crankshaft bearing
caps, procedure a. above, and remove bearings from
(6) Remove crankshaft and remove upper
d. Cleaning. Clean all parts with SD and dry them
thoroughly. Use a soft wire probe or stiff bristle brush to
clean all oil passages.