TM 10-4320-307-24
4-17
CRANKSHAFT ASSEMBLY REPLACE/REPAIR (CONT)
9.
Inspect crankshaft thrust surfaces. If slightly worn or grooved, smooth out and polish surfaces with wet crocus cloth.
Make sure to leave a 0.1693 to 0.1772 inch (4.30 to 4.50 mm) radius between thrust surface and journal.
10. Inspect thrust rings for nicks. scratches, cracks, or other damage. Replace If damaged. Measure thickness of thrust
rings. Replace rings if they are not the same thickness.
11. Measure connecting rod journals as follows:
a.
Measure diameter of each connecting rod
journal (4) at points A and B along axes X
and Y with micrometer.
b.
The minimum acceptable diameter for con-
necting rod journal (4) is 3.122 inches (79.298
mm). If any measurement is outside specified
limits, crankshaft must be replaced. However, if
connecting rod journals are evenly worn, not
out-of-round, and crankshaft journal diameters
are within specified limits, the condition may be
rectified by replacing connecting rod bearing
shells in accordance with paragraph 4-16.
Crankshaft Journal Diameters - Inch (mm)
Journal
Minimum
Maximum
Worn Limit
Connecting
3.1235
3.125
3.122
Rod
(79.337)
(79.375)
(79.298)
c.
If measurements at point A and B indicate more than 0.0005 inch (0.013 mm) taper per length of journal (4)
and/or one set is outside specified limits, the journal is worn into a conical shape and crankshaft must be
replaced.
d.
If measurements along X and Y axes differ. and/or one set is outside specified limits. journal is worn into an oval
shape.
e.
Measure width of connecting rod journals.
f.
Measure fillet radius at each connecting rod journal using fillet ball gauge set. Fillet radius should measure from
0.1693 to 0.1722 inch (4.30 to 4.50 mm). If any fillet measurement is out of limits, replace crankshaft. Fillet must
blend smoothly into journal cheek and must be free of scratches. Polish and smooth any slight imperfections with
crocus cloth wet with lubricating oil.
12. Check connecting rod journal bearing clearance in accordance with paragraph 4-16.
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