TM 5-3895-383-241.The serviceman must be very careful to use Plastigagecorrectly. The following points must be remembered:a.Be sure that the backs of the bearings and the boresare clean and dry.b.The bearing locking tabs must be properly seated intheir slots.c.The crankshaft must be free of oil where it is incontact with the Plastigage.d.If the main bearing clearances are checked with theengine upright or on is side, the crankshaft must besupported. Use a jack under an adjacent crankshaftcounterweight, and hold the crankshaft against thecrown of the bearing. If the crankshaft is notsupported, the weight of the crankshaft will causeincorrect readings.e.Put a piece of Plastigage on the crown of the bearinghalf that is in the cap. Do not allow the Plastigage toextend over the edge of the bearing.f.Install the bearing cap using the correct torque-turnspecifications. Do not use an impact wrench totighten the bearing cap mounting bolts. Be careful notto dislodge the bearing when the cap is installed.g.Do not turn the crankshaft with the Plastigageinstalled.NOTE:When using Plastigage to measure bearingclearances, the readings can sometimes beunclear. For example, all parts of the Plastigageare not the same width. Measure the major widthto be sure they are within specification range.h.Carefully remove the bearing cap, but do not removethe Plastigage. Measure the width of the Plastigagewhile it is in the bearing cap or on the crankshaftjournal. See the photograph which illustrates this.i.Remove all Plastigage before reinstalling the bearingcap.8-59/(8-60 blank)
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