What was found
PILOT EXPERIENCED RPM DROP, LOSS OF OIL PRESSURE, AND ROUGHNESS. LANDED ON CITY STREET. NO AIRCRAFT DAMAGE. FOUND OIL APPARENTLY EXHAUSTED THROUGH CRANKCASE BREATHER. NR 4 CYLINDER PISTON BURNED THROUGH AFT SIDE UNDER RINGS .3750 INCH HOLE. NR 3 CYLINDER CONNECTING ROD BROKEN LOOSE AT END CAP. PUNCTURED BOTTOM OF CRANKCASE. NOTE: APPROX 8 FLIGHT HOURS PREVIOUSLY, CYLINDER COMPRESSION CHECKS WERE ALL IN THE MID 70'S, OVER 80.