What was found
DURING CRUISE FLIGHT, A LOUD NOISE WAS HEARD COMING FROM THE ENGINE COMPARTMENT. FOLLOWED BY AN AIRFRAME VIBRATION, WHICH WAS FOLLOWED BY AN ENGINE SHUT DOWN. AFTER LANDING A LARGE HOLE WAS FOUND IN THE ENGINE CRANKCASE ABOVE THE NR 5 CYLINDER. DURING THE TEARDOWN INSPECTION, IT WAS NOTED THAT THE PISTON COOLING NOZZLE ASSEMBLIES HAD NOT BEEN INSTALLED. IT APPEARS THAT SOMETIME DURING THE ASSY OF THE ENGINE, A STD-1339, PLUG WAS INSTALLED INSTEAD OF A COOLING NOZZLE. THE PLUG EFFECTIVELY BLOCKS OFF THE FLOW OF OIL TO THE BASE OF THE CYLINDERS PREVENTING THEM FROM GETTING ANY ADDITIONAL COOLING AND LUBRICATION.