Accident Sequence
During a night forced landing following a total loss of engine power, the pilot maneuvered the airplane to avoid telephone poles. The aircraft subsequently struck crops and nosed over.
Engine Examination
The accident airplane had undergone a cylinder overhaul 166.5 hours prior to the event. At that time, the owner requested the installation of used serviceable components. A serviceable exhaust valve and piston were installed in the #4 cylinder. Post-accident, metal pieces were found in the intake tubes, engine, and oil pump. The #4 cylinder piston was broken into numerous pieces, and the exhaust valve head was separated from the valve stem. Damage to the #4 cylinder valves and piston precluded metallurgical examination to determine the mode of failure. The #4 connecting rod was separated from the crankshaft. The connecting rod bearings were found coated with oil and without evidence of lack of lubrication.
Occupant Restraint Examination
Testing of both front lap belts, which failed during the accident, and both front shoulder harnesses found that the belts and shoulder harnesses did not meet manufacturer's specifications.