TM 5-4310-354-14
crankshaft must be reground to
2. Measure
the
crankshaft
0.010, 0.020, 0.030, 0.040, or 0.060
journals, and compare these
inch (0.254, 0.508, 0.762, 1.016, or
measurements to the diameters
1.524 mm) undersize. Proceed as
required for various undersize
follows:
bearings shown in table 7-1.
These
measurements
will
1. Prior to grinding a crankshaft,
determine the size to which the
check carefully for cracks which
crankshaft journals must be
start at an oil hole and follow the
reground.
journal surface at an angle of
450 to the axis.
Any
3. If one or more main or
crankshafts with such cracks
connecting rod journals require
must be rejected, as these
grinding, then all main or all
cracks indicate torsional fatigue.
connecting rod journals must be
Grinding of the shaft will
ground to the same required
increase the stress at the cracks
size.
causing eventual failure.
Table 7-1. Crankshaft Journal and Crankpin Dimensions
Connecting rod journal
Main bearing journal
Bearing sizes
dia "A"
dia "B"
Inches
Millimeters
Inches
Millimeters
Inches
Millimeters
Standard
2.3730-2.3740
60.2742-60.2996
2.8734-2.8744
72.9844-73.0098
0.010 undersize
0.254
2.3630-2.3640
60.0202-60.0456
2.8634-2.8444
72.7304-72.7558
0.020 undersize
0.508
2.3530-2.3540
59.7662-59.7916
2.8534-2.8544
72.4764-72.5018
0.030 undersize
0.762
2.3430-2.3440
59.5122-59.5376
2.8434-2.8444
72.2224-72.2478
0.040 undersize
1.016
2.3330-2.3340
59.2582-59.2836
2.8334-2.8344
71.9684-71.9938
0.060 undersize
1.524
2.3130-2.3140
58.7502-58.7756
2.8134-2.8144
71.4604-71.4858
7-67
