TM 9-2320-272-24-4
5-8. CRANKSHAFT AND MAIN BEARINGS MAINTENANCE (Contd)
b. Cleaning and Inspection
WARNING
Drycleaning solvent is flammable and toxic. Do not use near open
flame and always have a tire extinguisher nearby when solvents
are used. Use only in well-ventilated places, wear protective
clothing, and dispose of cleaning rags in approved container.
Failure to do this may result in injury or death to personnel and/or
damage to equipment.
Clean crankshaft (2) and crankshaft gear (6) with drycleaning solvent. For cleaning instructions,
1.
refer to para. 2-14.
Inspect crankshaft gear (6) for breaks, cracks, or chips. If broken, cracked, or chipped, replace
2.
crankshaft (2) assembly.
Wipe rear No. 7 main bearing journal thrust flange (1) clean and check stamping (4) on
3.
shaft web (5). Stamped numbers show standard or oversize thrust rings both front and rear.
Inspect rear No. 7 main bearing journal thrust flange (1) for scratches or scoring. If scratched or
4.
scored, regrind and stamp shaft web (5) accordingly.
CAUTION
If any one bearing shell half is damaged, all bearing shells must
be discarded. Not doing so will vary oil clearance limits when
installed in engine and cause lubrication problems.
Wipe lower and upper half main bearing shell (7) clean and inspect for pits, chips, and scratches.
5.
If pitted, chipped, or scratched, replace bearing set.
Measure thickness of lower and upper half main bearing shell (7). If thickness is less than 0.1215
6.
in. (3.086 mm), replace bearing set.
Wipe crankshaft main bearing journals (3) clean with lint-free cloth and inspect for out-of-round
7.
condition. Measure out-of-round condition with micrometer. If out-of-round more than 0.002 in.
(0.05 mm), replace crankshaft (2).
Measure outer diameter of crankshaft main bearing journals (3) with micrometer. If outer diameter
8.
is less than 4.4975 in. (114.237 mm), repair and stamp on front counterweight (8) accordingly.
Wipe lower and upper half rod bearing shell (7) clean and inspect for pits, chips, and scratches. If
9.
pitted, chipped, or scratched, replace bearing set.
Measure lower and upper half rod bearing shell (7) thickness with micrometer. If thickness is less
10.
than 0.071 in. (1.80 mm), replace bearing set.
Wipe crankshaft rod journals (9) clean with lint-free cloth and measure outer diameter with
11.
micrometer. If outer diameter is less than 3.122 in. (79.30 mm), repair and stamp on front
counterweight (8) accordingly.
Measure outer diameter of rear counterweight seal flange (10) with micrometer. If outer diameter is
12.
under 5.997 in. (152.94 mm), replace crankshaft (2).
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