What was found
PILOT REPORTED FAILURE OCCURRED AFTER TAKEOFF WHILE TURNING DOWN WIND AT 1,100 FEET AGL. A LOUD BAG HEARD FROM THE ENG WITH SMOKE AND OIL COVERING W/S FOLLOWED BY A LOSS IN OIL PRESSURE. ENG SHUT DOWN, UNEVENTFUL DEAD STICK LANDING MADE. INVEST REVEALED A HOLE IN THE COWLING AND ACFT COVERED WITH OIL FROM ENG. REMOVED TOP COWLING TO FIND NR 1 CYL HEAD SEPARATED FROM CYL BARREL. ENG HAS 894.0 HRS SMOH WITH CERMICROME CYL. A COMP TEST, 20 HRS BEFORE FAILURE OCCURRED, WAS 72/80. NO INDICATION OF LEAKAGE; CYL HEAD APPEARED CRACKED ABOUT HALF-WAY AROUND CYL BARREL FOR SOME TIME. FAILURE OCCURRED WHERE CYL HEAD THREADS ON TO BARREL. RECOMMEND FAA INVESTIGATE. SUSPECT CAUSE TO BE MFG OR CYL O/H PROCESS.