TM 5-3810-300-24&P-3
1.3 Crankshaft
Fig. 2. Crankshaft, Timing Gear and Oil Pump Drive Gear Assembly - Four Cylinder Engine
15. Remove the cylinder head.
If the crankshaft shows evidence of excessive
overheating, replace the crankshaft since the heat
16. Remove the connecting rod bearing caps.
treatment has probably been destroyed.
17. Remove the main bearing caps.
Used crankshafts will sometimes show a certain amount
of ridging caused by the groove in the upper main
18. Remove the thrust washers from each side of
bearing shell or lower connecting rod bearing shell (Fig.
the rear main bearing.
3). Ridges exceeding .0002" must be removed. If the
ridges are not removed, localized high unit pressures on
19. Remove the pistons, connecting rods and liners.
new bearing shells will result during engine operation.
20. Remove the crankshaft, including the timing
The ridges may be removed by working crocus cloth, wet
gear and oil pump drive gear (Fig. 2).
with fuel oil, around the circumference of the crankshaft
21. Refer to Section 1.7.5 for removal of the
crankshaft timing gear and Section 4.1 for the
procedure covering removal of the oil pump drive
gear.
Inspection
After the crankshaft has been removed, clean and
inspect it thoroughly before reinstalling it in the engine.
Remove the plugs and clean out the oil passages
thoroughly with a stiff wire brush. Clean the crankshaft
with fuel oil and dry it with compressed air. Then reinstall
the plugs.
Inspect the keyways for evidence of cracks or wear.
Replace the crankshaft, if necessary.
Fig. 3. Typical Ridging of Crankshaft
PAGE 62
