The certificated private pilot, the sole occupant, was on a cross country business flight when the engine quit. The pilot made a forced landing about 250 feet short of a dirt airstrip. The airplane was destroyed by impact and a post impact fire, and the pilot was fatally injured. Examination of the engine revealed a broken crankshaft on the crankcheek adjacent to the number 1 cylinder. The crankshaft had been replaced 42 hours prior to the accident. The crankshaft was supplied from an engine with an accumulated total time of about 1,000 hours of operation that had previously sustained a separation of the number 1 cylinder from the engine case. After an inspection, the crankshaft was determined to be serviceable and installed in the accident airplane's engine. Metallurgical examination revealed a high cycle fatigue failure consistent with surface initiated cracking. A metallurgical report indicated that surface cracking would not be expected in the area of failure unless prior damage to the surface had occurred.