Incident Overview
A pilot reported that before departure, the spark plugs were cleaned and inspected, and the engine was serviced with eleven quarts of oil. Approximately three hours into the flight, the aircraft encountered instrument meteorological conditions (IMC) with rain. Shortly thereafter, the oil pressure dropped to zero and the engine began running rough.
Emergency Response
The pilot secured the engine, declared an emergency, and initiated a descent under IMC with vectors provided by Kansas City Air Route Traffic Control Center (ARTCC). After breaking out of the clouds, the only available landing area was a rolling pasture with a drainage ditch across the intended landing path.
Post-Accident Examination
A post-accident examination of the engine revealed that the failure was caused by oil starvation due to the failure of the number six pushrod and damage to the crankcase.