TM  10-3930-638-24&P 4-2.   ENGINE   MAINTENANCE   (cont) f. Pistons and Connecting Rods (cont). STEP LOCATION ITEM ACTION REMARKS INSPECTION   (cont) 8 d. Second piston ring Measure Use feeler gauge. If measurement exceeds (cont) side clearance 0.008 inch, replace piston NOTE Top piston ring clearance cannot be checked. e. Piston diameter Measure Use  micrometer.  Measure  across  thrust face at bottom of piston, perpendicular to piston pin holes, as shown. If piston diameter is less than 3.9940 inches, re- place  piston 9 Piston pin (9) Outside  diameter Measure Use micrometer. Replace if measurement is less than 1.2495 inches 10 Retaining  ring  (8) Inspect Check  for  damage  and  loss  of  resiliency. Replace if damaged or resiliency is lost NOTE Replace connecting rod as an assembly if side clearance check, performed in step 1 of removal, exceeded 0.011 inch. 4-46