Figure 3-91. Crankshaft fatigue cracks.

Figure 3-91. Crankshaft fatigue cracks.

(8) Check thrust surfaces for evidence of

oil seal contact

excessive wear or roughness. In many instances

this point.

o n l y slight grinding or "dressing up" of the thrust

surfaces is necesaary. In such cases, use of new

Slight ridges

variation may be removed with crocus cloth, wet with

s t a n d a r d thrust washers will probably hold the end

fuel oil. The crankshaft should be rotated at intervals

t h r u s t clearance within the specified limits of 0.004

to remove ridges from the complete circumference of

to 0.011 inch for new parts or a maximum of 0.018

the shaft without disturbing the concentricity y. Ridges

i n c h with a used crankshaft. otherwise, it may be

which approach 0.0005 inch or greater should first be

necessary to use 0.005 inch oversize rear thrust

cleaned up with 120 grit emery cloth, followed by use

of 240 grit emery cloth for finishing. Crocus cloth,

washers.

wet with fuel oil, should then be used for final polish-

( 9 ) Inspect keyways for evidence of cracks or

ing. If excessive wear or grooving is present, and can-

worn condition, and replace shaft if necessary.

not be cleaned up satisfactorily, the oil seal may be

(10) Carefully inspect crankshaft in area of

pressed in the flywheel housing and front cover

f r o n t and rear oil seal contact surface for evidence

approximately 1/8 inch from its original position.

of rough or grooved condition. Any imperfections of