ARMY TM 9-2815-256-24 AIR FORCE TO 38G1-96-2 MARINE CORPS TM 2815-24/5 CAUTION 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. (3) Install all the orifices and tighten to 84 in-lbs (10 Nm). 3-43.3.  Repair. If crankshaft is to be reground, use following recommended guidelines. CAUTION Crankshaft   grinding   should   be   done   only   by   experienced   personnel   on   equipment   capable   of maintaining crankshaft size and finish specifications. CAUTION If undersize bearings are used, check bearing clearance after bearing caps have been tightened to specified torque.  If undersize bearings are too tight and clearance is not within specifications, journal and bearing will be wiped clean of all oil.  This would result in premature wear of parts. CAUTION When grinding crankshaft, also grind fillet radii to specifications.  This is necessary to prevent stress risers in fillet areas during grinding. NOTE In addition to standard size main and connecting rod bearings, 0.002, 0.010, 0.020, and 0.030 inch (0.05, 0.25, 0.51, and 0.76 mm) undersize bearings are available. NOTE The 0.002 inch (0.05 mm) undersize bearings are used normally to compensate for slight even wear on crankshafts.  Regrinding is usually unnecessary when this size bearing is used. NOTE To maintain the correct end play, the two piece main bearing with three piece thrust washer set can be used to replace the two piece flanged main bearings if desired. a. Compare crankshaft journal measurements taken during inspection and determine size which journals are to be reground. b. If  one  or  more  main  or  connecting  rod  journals  requires  grinding,  then  grind  all  of  main  journals  or  all  of connecting rod journals to same required size.  Grind clockwise (opposite engine rotation). c. All journal fillets radii must be free of any sharp grind marks or scratches.  Fillet must blend smoothly into journal and crank cheek.  Radius may be checked with a fillet gage. 3-186