ARMY TM 9-2815-259-24
AIR FORCE TO 38G1-125-2
MARINE CORPS 09249A/09246A-24
Refer to Table 5-5 for bearing-to-journal clearance.
Measure assembled inner diameter of main bearing caps as follows:
Remove bearing inserts from caps and engine block. Keep inserts in correct order if they
are to be reused.
Clean caps in solvent and dry with compressed air.
Inspect caps for serviceability. Small burrs or nicks on flat surfaces may be removed with a
file. Use a medium-grit polishing cloth to dress up curved bearing surfaces.
Install bearing caps in engine block. Refer to Table 5-5 for values.
Measure inner diameter of bore without bearings. Refer to Table 5-5 for main bearing bore
inner diameter without bearings.
If bearing caps are damaged or bore is not within specification, replace cap and bore to
Main bearing cap line boring should be done only by experienced personnel
on equipment capable of maintaining the bore specifications. Refer to
Table 5-5 for dimension from centerline of bore-to-top of deck of engine
Replacement bearing caps are supplied with bearing bore unfinished.
Inspect piston cooling orifices as follows:
Inspect each cooling orifice to make sure it is not plugged or damaged.
Use a soft wire and compressed air to clean orifice. Replace, if condition is questionable.
A piston cooling orifice failure could cause damage to pistons, piston pins,
rod pin bushings, and liners. If a piston cooling orifice is left out of block
during assembly, low or no oil pressure will result.
Install all the orifices and tighten to values in Table 5-5.