ARMY TM 9-2815-259-24
AIR FORCE TO 38G1-125-2
MARINE CORPS 09249A/09246A-24
If engine has previously had a major overhaul and undersized bearing
inserts were used, above listed inner diameter and outer diameter
dimensions may not be the same as those recorded. However, oil clearance
should be within specifications. Oil clearance is 0.0016-0.0043 inch (0.041
to 0.109 mm).
Use crankshaft journal outer diameter measurements to determine if journal is out-of-round
or tapered. Refer to Table 5-5 for journal out-of roundness wear limit and journal taper-per-
inch of journal length wear limit.
If journals are tapered, out-of-round, scored, or damaged, crankshaft should be ground.
Refer to paragraph (e). Proper undersize bearings should be installed after grinding.
Measure main thrust journal width and thrust bearing width, refer to Figure 5-69, as follows:
Measure width of main thrust journal with an inside micrometer.
Refer to Table 5-5 for new main thrust journal width.
If width is not within specification, recondition crankshaft and install an oversize thrust
washer set. If width is correct, measure main thrust bearing width.
FIGURE 5-69. MEASURING MAIN THRUST JOURNAL AND THRUST BEARING WIDTH
Measure width of thrust bearing using an outside micrometer.
Refer to Table 5-5 for new main thrust bearing width.