|
| |
TM 5-4320-306-24
4-12.
REPLACE/REPAIR CRANKSHAFT ASSEMBLY (Continued)
c.
However, if the crankpins are evenly worn, not out-of-
round, and the crankshaft journal diameters are within
specified limits, the condition may be rectified by
replacing connecting rod bearing shells. Replace in
accordance with paragraph 4-11. Check the radial
clearance of the bearing shells. If it exceeds the
tolerance limits of 0.0016 to 0.0118 inch (0.04 to 0.3
mm), the crankshaft must be replaced.
d.
If the measurements at points 1 and 2 differ by more
than 0.0028 inch (0.07 mm) and/or any one set is
outside the tolerance limits, the crankpin is worn into a
conical shape and the crankshaft must be replaced. If
the measurements along axes A and B differ by more
than 0.0028 inch (0.07 mm) and/ or one set is outside
the tolerance limits, the crankpin is worn into an oval
shape and the crankshaft must be replaced. For both
these out-of-round conditions, also check connecting
rods, pistons, and cylinders for unusual wear.
e.
The crankpin width at point 3 should be 1 4173 to 1.4189 inches (36.0 to 36.039 mm). The fillet radius
measurement should be 0.1693 to 0.1772 inch (4.30 to 4.50 mm). If either measurement is outside the
specified limits, the crankshaft must be replaced.
7
Inspect crankshaft main bearing journals.
a.
Measure diameter of each crankshaft main bearing
journal (1) at points 1 and 2 and along axes A and B with
micrometer. Measure width of journal at point 3. Measure
radius of fillets (2) between main bearing journal and
crank cheek (3).
b.
Normal main bearing journal diameter should be 2.8728
to 2.8736 inches (72.97 to 72.99 mm). If any
measurement
is
outside
the
specified
limits,
the
crankshaft must be replaced. However, if journals are
evenly worn, not out-of-round, and crankpin diameters are
within specified limits, only main bearing bushings need
be replaced.
c
Replace bearing bushings in accordance with paragraph
4-13. Make sure that main bearing bushing radial
clearance does not exceed 0.0020 to 0.0118 inch (0.052
to 0.3 mm). If specified limits are exceeded, the
crankshaft must be replaced.
d.
If measurements at points 1 and 2 differ by more than 0.0028 inch (0.07 mm) and/or one set is outside the
specified limits, the journal is worn into a conical shape and crankshaft must be replaced. If measurements
along axes A and B differ by more than 0.0028 inch (0.07 mm) and/or one set is outside the specified
limits, the journal is worn into an oval shape and crankshaft must be replaced.
4-97
|
