ARMY TM 9-2815-260-24 AIR FORCE TO 38G1-126-2 MARINE CORPS TM 09244A/09245A-24 5-93 (2) After thorough cleaning, inspect and clean cylinder block as follows: NOTE All components (including piston cooling orifices, soft plugs and oil gallery plugs) must be removed from the cylinder block for inspection and cleaning. (a) Inspect each piston orifice (1, Figure 5-79) to make sure it is not plugged or damaged.   Cooling orifices deliver approximately 0.4 gallon per min (1.50 liters/min) oil flow. (b) Use soft wire brush and compressed air to clean orifice.  Replace if condition is questionable, refer to paragraph 5.4.7. CAUTION A piston cooling orifice failure could cause damage to piston, piston pins, rod pin bushings, and liners.  If a piston cooling orifice is left out of assembly, low or no oil pressure will result. (c) Inspect all passages and crevices to ensure they are cleared of sludge and grease. (d) Inspect all coolant passages to ensure they are cleared of any lime deposits and scale. CAUTION Do not file line support flange excessively.  Excess filing can damage liner support flange and may result in an improper fit.  Thoroughly clean all filings from cylinder block (2, Figure 5-81). Failure to comply may result in engine damage. (e) Be sure liner support flange (1, Figure 5-81) is free of any burrs.  If burrs are present, use a small half-moon file and lightly file (in a circular motion) burr off at approximately 60 degree angle.  Do not let file hit top of cylinder block while filing. (f) Carefully inspect cylinder block for cracks or damage.  Replace block of there is evidence of physical damage. (g) When determined that cylinder block is serviceable, clean out threads for cylinder head capscrews in top deck of cylinder block using 1/2-13 UNC-2A x 4.00 inches (101.6 mm) long tap (3).  Use compressed air to remove any debris or fluid which may be present in the tapped holes after cleaning. (h) Inspect O-ring bore.  If required, clean O-ring bore using O-ring bore cleaning brush as follows: 1 Chuck bore cleaning brush in 1/2 inch drill motor.  Rotate brush and move in an up and down motion in O-ring bore. 2 Thoroughly clean all lime deposits from O-ring bore.