What was found
(CAN) PILOT REPORTED VIBRATION ON LT & RT ENGINE ON RUN-UP. INSPECTED BOTH ENGINES, FOUND GOOD COMPRESSION, NO BROKEN ENGINE MOUNT (COMMON ON THIS AIRCRAFT). REMOVED LIFTERS FOUND BADLY DAMAGED, DAMAGE ON CAMSHAFT AS WELL. FRONT SURFACE MISSING PIECES ON LIFTERS. BOTH ENGINES REMOVED (& PROP FOR FLUSHING) SEND TO LEAVENS AVIATION FOR REPAIR. NOTE: LIFTERS INSPECTED ON 500 HOUR SINCE OVERHAUL, NO DAMAGE AT THAT TIME. DAMAGE OCCUR WITHIN 150 HR SINCE THAT INSPECTION.