Thrust Bearing Clearance

TM-9-2815-255-24_205_1

Thrust Bearing Clearance:
Measure main thrust journal width and thrust bearing width, refer to FIGURE 1, as follows:
(1)Measure width of main thrust journal with an inside micrometer.
(2)New main thrust journal width is 1.531 to 1.535 inches (38.90 to 39.00 mm).
(3)If width is not within specification, recondition crankshaft and install an oversize thrust washer set. If widthis correct, measure main thrust bearing width.FIGURE 1. Measuring Main Thrust Journal and Thrust Bearing Width.

(4)Measure width of thrust bearing using an outside micrometer.
(5)New main thrust bearing width (standard size) is 1.528 to 1.530 inches (38.80 to 38.85 mm).
(6)New main thrust bearing clearance (thrust journal width minus thrust bearing width) is 0.002 to 0.008 inch(0.05 to 0.20 mm).
(7)Maximum allowable thrust bearing clearance is 0.015 inch (0.38 mm). Oversize thrust washer sets have thrust washers that are 0.007 inch (0.18 mm) over size.
Measure assembled ID of main bearing caps as follows:
(1)Remove bearing inserts from caps and engine block. Keep inserts in correct order if they are to be reused.
(2)Clean caps in dry cleaning solvent (P-D-680) and dry with compressed air.
(3)Inspect caps for serviceability. Small burrs or nicks on flat surfaces may be removed with a file. Use amedium-grit abrasive cloth to dress up curved bearing surfaces.
(4)Install bearing caps in engine block. Tighten capscrews to 85 ft-lbs (115 Nm).
(5)Measure ID of bore without bearings. Main bearing bore ID without bearings should be 3.325 to 3.326inches (84.45 to 84.48 mm).
(6)If bearing caps are damaged or bore is not within specification, replace cap and bore to specification.
CAUTION
Main bearing cap line boring should be done only by experienced personnel on equipmentcapable of maintaining the bore specifications. Make sure that dimension from centerline ofcore-to-top deck of engine block does not exceed 11.889 to 11.894 Inches (301.98 to 302.11 mm)

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