TM 10-4320-307-244-17CRANKSHAFTASSEMBLY REPLACE/REPAIR (CONT)7.Measure crankshaft main bearing journals as follows:a.Using micrometer, measure diameter of eachcrankshaft main bearing journal (1) at points Aand B, along axes X and Y.b.The maximum acceptable diameter for journalis 4.4975 inches (114.237 mm). However, ifjournals are evenly worn, not out of round. andcrank pin diameters are within specified limits,only main bearing bushings need be replaced.Crankshaft Journal Diameters - Inch (mm)JournalMinimumMaximumWorn LimitMain4.49854.5004.4975Bearing(114.262)(114.30)(114.237)c.If measurements at points A and B indicate more than 0 005 inch (0.013 mm) taper per length of journal, and/orone set is outside specified limits, journal is worn In a conical shape and crankshaft must be replaced.d.If measurements along X and Y axes differ and, or one set is outside specified limits. journal is worn into an ovalshape.NOTEFor both above out-of-round conditions, also check connecting rods. pistons. cylinders,and main bearing bushings for unusual wear.e.Measure width of crankshaft journals.f.Measure fillet radius at each crankshaft main journal using fillet ball gauge set (3). Fillet radius should measurefrom 0.1693 to 0.1772 inch (4.30 to 4.50 mm). If any fillet measurement is out of limits. replace crankshaft. Filletmust blend smoothly into journal check. and must be free from scratches. Polish and smooth any slightimperfections with crocus cloth wet with lubricating oil.8.Check crankshaft main bearing clearances as follows:aAssemble upper bearing shell, lower bearing shell and bearing cap to cylinder head, using hexagon screws andwashers. Torque screws in accordance with installation instructions.b.Measure inside diameter of bearing shells.c.Subtract journal outside diameter (previously measured) from bearing shell inside diameter to obtain clearancebetween shell and journal.Bearing Clearance - Inch (mm)BearingNew DimensionJournalMinimumMaximumWorn LimitMain0.00150.00500.0070Bearing(0.038)(0.127)(0.178)4-128
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