As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE FLYING, NR 3 ROCKER SHAFT ON EXHAUST VALVE EXITED THE AIRCRAFT CAUSING THE ENGINE TO LOSE POWER. AIRCRAFT MADE A FORCED LANDING INTO A PLOWED FIELD CAUSING THE AIRCRAFT TO FLIP OVER. THE ENGINE HAD 185 HOURS SINCE OVERHAUL, PART COULD NOT BE FOUND, BUT SUSPECT IT FAILED IN THE THREAD AREA NEXT TO THE SMALL NUT.