Incident
During flight, the pilot observed a loss of manifold pressure and oil pressure. Shortly after, the engine began emitting loud noises. The pilot elected to turn back toward Grand Junction (Colorado) and executed a forced landing on a slippery road. Upon touchdown, the aircraft skidded and the landing gear collapsed.
Investigation
Following the incident, Teledyne-Continental conducted an examination of the engine. They determined that a thrust washer half had been omitted during the engine's manufacturing process. This omission allowed excessive crankshaft movement, which in turn side-loaded and failed the number two connecting rod and damaged the number one connecting rod. The engine failure precipitated the forced landing.
Probable Cause
The probable cause of the accident is the engine manufacturer's omission of a thrust washer half during assembly, which permitted abnormal crankshaft movement and subsequent connecting rod failure.