CLEANING - TM-10-3930-638-24-P0806

TM 10-3930-638-24&P

4-2. ENGINE MAINTENANCE (cont)

d. Crankshaft and Main Bearings (cont).

REMARKS

ACTION

ITEM

LOCATION

STEP

CLEANING (cont)

WARNING

Wear safety glasses when drying parts with compressed air. Fail-

ure to do so could cause serious injury to eyes and possible blind-

ness. If you hurt your eyes or if a foreign object is blown into

your eyes, seek medical attention immediately.

All parts

Clean

Use cleaning solvent P-D-680. Dry thor-

oughly with moisture free compressed

air or clean cloths

INSPECTION

Key (10)

Inspect

Inspect for cracks, damage and wear. Re-

place if cracked, damaged or worn

a. Crankshaft overall

Crankshaft (8)

Inspect

Inspect surfaces for rough or grooved con-

dition. Inspect for scoring, pits, cracks,

damage, and evidence of overheating. If

any of these conditions observed, replace

crankshaft

b. Crankshaft main

Measure

Use micrometer. Measure front and rear of

bearing journals

each journal. If diameters are smaller than

2.8730 inches use undersize bearing liners

(0.002 inch)

NOTE

When main bearing journals are worn more than 0.002 inch, grind

undersize to following dimensions:

Outer Diameter

Grind

Undersize (inch)

to (inches)

0.002

2.2460 to 2.2470

0.010

2.2380 to 2.2390

0.020

2.2280 to 2.2290

0.030

2.2180 to 2.2190

If one or more journals are to be ground, then grind all journals.

c. Crankshaft main

Measure

Measure 90 degrees from first measurement

bearing journals

for out-of-roundness. If out-of-roundness

exceeds 0.0005 inch, regrind journal and

use undersize liners.

d. Crankshaft connect-

Measure

Use micrometer. Measure front and rear of

ing rod journals

each journal, checking taper. If taper ex-

ceeds 0.001 inch, regrind journal

4-28