As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THROUGH 7000 FELT A SLIGHT SHUDDER. WHILE LEVELING AT 9500, NOTICED OIL PRESSURE GOING DOWN. PROP WENT TO FLAT PITCH. OIL PRESSURE NOW IN YELLOW ARC. DECLARED AN EMERGENCY. PULLED ENGINE TO IDLE AND BEGAN A DESCENT TO AIRPORT. LANDED LONG AND BLEW MAIN TIRES WHILE BRAKING HEAVILY. STOPPED SHORT OF OVERRUN. INSPECTION FOUND A SECTION OF CYLINDER WALL HAD DELAMINATED AND PASSED THROUGH THE ENGINE.