What was found
PRIOR TO DISASSEMBLY, A 'GRATING' OR 'RATCHETING' NOISE COULD BE HEARD AT A CONSTANT LOCATION DURING CRANKSHAFT ROTATION WITH THE NOSE OF THE ENGINE RACING DOWN. THE ACCESSORY CASE AND COLLECTOR CASE WERE REMOVED AS A UNIT. UPON REMOVAL, A SINGLE GEAR TOOTH WAS FOUND ON THE ENGINE CRANKCASE. CLOSER EXAMINATION SHOWED THE TOOTH HAD BROKEN FROM THE IMPELLER DRIVE SHAFT (P/N 6514). THE REMAINING TEETH WERE NOTED AS SEVERELY WORN. DURING OIL SCREEN AND ENGINE SUMP OIL EXAMINATION, NO METAL COULD BE NOTED VISUALLY.