Incident Overview
While cruising at 8,000 feet at night, the pilot of the airplane reported a sudden violent vibration. In response, the pilot adjusted the mixture, switched fuel tanks, and changed the propeller setting, but these actions did not alleviate the vibration. The pilot then reduced power to mitigate the vibration.
Diversion and Approach
Air traffic control vectored the pilot toward the nearest airport. The pilot located the runway; however, due to fog and inadequate visibility, the pilot was unable to dissipate excess altitude and subsequently overshot the runway.
Post-Incident Examination
An examination of the engine revealed that the number 2 cylinder exhaust valve had failed due to fatigue.