N808HC

The pilot reported that during cruise flight the airplane suddenly started shaking violently. He reduced power and the shaking was not as bad. The pilot selected a field and attempted an off-airport landing. During the landing, the "nose wheel dug in" and the airplane nosed over. The airplane sustained damage to the propeller, nose landing gear, wings, and vertical tail. Examination of the airplane's engine revealed that the number 5 piston was fragmented. The engine had last been overhauled on April 23, 1993, and had accumulated 740 hours since that overhaul. The logbook entry for the piston showed that it was a Superior Air Parts piston, part number SA640518.