Incident Overview
A pilot executed an off-airport landing after experiencing a rough-running engine, oil obscuring the windshield, and a radio report indicating smoke trailing from the aircraft. The landing was made on a dirt road. During the rollout, the aircraft struck a ditch and nosed over.
Engine Examination
Subsequent examination of the engine disclosed an intake manifold seal that was leaking at its attachment point to the number 4 cylinder. Additionally, the number 4 piston contained a burned hole. The propeller shaft seal had been displaced forward onto the engine propeller shaft, and the engine oil supply had been vented overboard through the engine breather and around the propeller shaft.
Recent Overhaul
The engine had undergone an overhaul only 11 hours prior to the accident.
Conclusion
The source provides details of the mechanical findings but does not assign a probable cause or indicate any injuries or fatalities.