CYLINDER BLOCK. - TM-10-3930-622-140134

(9) Replace remaining bearings in same

e. Inspection and repair of crankshaft.

manner.

(1) Inspect

crankshaft

journals

and

bearings for excessive wear, scoring, taper, out of

NOTE

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

damage.

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.

pounds.

(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.

6-82.

CYLINDER BLOCK.

(1) Remove bearing cap and place a piece of

0.002 by 1/2 by I inch shim stock in bearing cap (Figure

a. Removal.

Remove engine from the truck

6-38).

(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,

crankshaft (paragraph 6-81) and camshaft (paragraph 6-

clearance is correct.

Remove shim stock and

79).

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

block.

available. If this method is used, do not rotate crankshaft

(2) Remove dirt, carbon, and sludge.

with plastigauge in place.

Maximum allowable

(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.

compressed air.

NOTE

(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.

0.004 inch.

(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

(paragraph 6-80b.).

round. Move dial

(5) Mark and remove crankshaft bearing

caps, procedure a. above, and remove bearings from

caps.

(6) Remove crankshaft and remove upper

bearing halves.

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.

110