TM 5-4310-379-14
(k)
Clean crankshaft (3) with dry cleaning solvent and dry thoroughly.
(I)
Inspect keyway and replace crankshaft if cracked or worn.
NOTE
Maximum runout on the intermediate journal must not exceed .003 in. (.007 cm).
(m)
Using a dial indicator, check the main journal runout. If the runout exceeds .003 in. (.007 cm),
replace the crankshaft.
NOTE
The main bearing journal diameter is 3.499-3.500 in. (8.887-8.8900 cm) and diameter of connecting
rod journal is 2.749-2.750 in. (6.982-6.985 cm). Taper on journals of used shaft should not exceed
.0015 in. (.0038 cm), and out-of-round should not exceed .0010 in. (.0025 cm). The maximum taper
on new crankshaft is .0005 in. (.0012 cm) and maximum out-of-round is .00025 in. (.00063 cm).
(n)
Measure the main and connecting rod bearing journals. If measurements exceed the specified
limits, replace crankshaft.
(o)
Inspect crankshaft for cracks by using the magnetic particle method, fluorescent magnetic particle
method or fluorescent penetrant method.
(p)
Inspect oil seal for wear or damage.
(q)
Inspect bearing shells for scoring, pitting, flaking, chipping, cracking, loss of babbit, or signs of
overheating. If any of these defects are present, replace bearing shells.
(r)
Inspect back of bearing shells for bright spots which indicate they have been moving in caps or
cylinder block. If these spots are present, replace bearing shells.
NOTE
Minimum thickness of a worn main bearing shell is .153 in. (.388 cm).
(s)
Using micro meter ball attachment, measure the bearing shells, and if dimension is not within
specified dimension, replace shell.
NOTE
Clearance between main bearing journals and inside diameter of bearing shells, when installed,
shall not exceed .006 in. and .0014-.0044 in. (.0035-.0111 cm) for new parts.
(t)
Measure clearance between main bearing journals and inside diameter of bearing shells, if clearance
exceeds specified dimension, replace bearing shells.
5-97
