CAMSHAFT AND BEARINGS INSPECTION.

TM 10-3930-623-34

5. Check that all drilled oil passages in the block

3. Inspect cover (11) and gear faces for wear or

are unplugged, by blowing through them with shop

scoring. Check gear to cover side of gasket (12) for

compressed air. (Since all passages are drilled straight,

0.0015 to 0.006 inch maximum clearance.

they can be probed with wire or welding rod to unplug

them).

7-42. CRANKSHAFT INSPECTION. Inspect crankshaft

6. Check oil pan (28, figure 4-22) for leaks, dents,

(37, figure 4-28) as follows:

or deformations that might cause leakage of oil or

1. Measure main and connecting rod bearing

interference with crankshaft travel.

journals for any scoring, or wear in excess of 0.002 inch,

7. Inspect front and rear filler blocks (37 and 38) for

out-of-round in excess of 0.001 inch, or taper of the

damage.

journal in excess of 0.002 inch. If shaft exceeds given

8. Check expansion plugs (10 and 11) for condition

limits (13 and 18, figure 7-1) regrinding of the journals to

and security of installation. Discard any plugs in doubtful

the next standard undersize to fit available bearing

or bad condition.

inserts is required. Do not regrind any journal more than

0 040 inch undersize.

2. With crankshaft mounted in centers of V-blocks,

7-39. CAMSHAFT AND BEARINGS INSPECTION.

1. With camshaft (19, figure 4-23) installed in

check run-out at center main bearing journal. Straighten

block, use a piece of narrow (about 1/4 inch wide or

shaft if run-out exceeds 0.002 inch.

less) feeler stock to measure the bearing clearance.

Clearance greater than 0.004 inch requires checking

7-43. PISTON INSPECTION.

Inspect pistons (16,

diameter of shaft journals against 7, 8, 9 and 10, figure

figure 4-28) as follows:

7-1, to determine if bearings or shaft require

replacement.

1. Check piston visually for damage, carbon

2. Check rubbing surface of camshaft lobes for

coating or scores or scratches.

wear, scuffing or scratches. Discard shaft showing

2. Check piston dimensions against values given in

imperfections on the working surfaces.

22 through 27, figure 7-1.

3. Check camshaft lobe wear by use of dial

indicator and a 5/16 inch diameter rod. Remove valve

7-44. CONNECTING ROD, CONNECTING ROD AND

and replace with rod resting on tappet. Set dial indicator

MAIN BEARING INSPECTION. Inspect as follows:

to measure lift of rod as camshaft is rotated. Minimum

1. Check axial alignment of both bores of each

lift is 0.281 inch.

connecting rod. Bores must be parallel to within 0.002

inch at 4 inches from rod. Any bend or twist greater than

7-40. VALVES AND TAPPETS INSPECTION. Since

this must be corrected by bending or replacing

these items are so closely related, inspect them

connecting rod.

considering their relationship with each other, as follows:

2. Check thickness of rod bearing inserts (24,

1. Inspect exhaust valve seat inserts (3, figure

figure 4-28) against dimensions given in 12, figure 7-1.

4-23) and replace any that are loose, cracked or

damaged.

NOTE

2. Inspect valves (1 and 2) for burning, cracking, or

If crankshaft journal has been ground

carbon formation. Measure stem diameter for wear (5,

to standard undersize, add one-half

figure 7-1).

the nominal crankshaft undersize to

3. Inspect tappet face for wear or pitting. More

this dimension to get thickness.

than two small pits per tappet face calls for tappet

replacement.

3. Repeat step 2 for main bearing inserts (34, 35

4. Inspect valve springs (5, figure 4-23) for

and 36, figure 4-28).

pressure necessary to compress them to 1-45/64 inches

(6, figure 7-1). Replace weak springs.

7-45. DRIVE LINE AND CONTROL COMPONENT

5. Check valve guides (4, figure 4-23). Replace all

INSPECTIONS AND TESTS.

guides that are worn bell-mouthed, or exceed 1, figure

7-1.

7-46. TRANSMISSION AND TORQUE CONVERTOR

INSPECTION.

Perform the following inspection or

7-41. OIL PUMP INSPECTION. Inspect as follows:

disassembled transmission assembly.

1. Examine screen strainer (6, figure 4-26) for

1. Perform general inspection steps listed in

clogging or damage.

paragraph 7-5 through 7-13 as applicable to

2. Examine gears (13 and 16) and pump body (19) for

transmission parts.

wear indicating lack of clearance. Check gear-to-body

2. Inspect strainer element (9, figure 4-14) and all

clearances for 0.003 inch maximum clearance.

fluid passages for freedom from obstructions to fluid

flow.

7-14