On taxi back to the pit after landing, the engine quit. After retrieving the plane, the engine appeared to be locked up. Later, it turned roughly with what seemed like a bad bearing. Even later, the roughness went away. I noticed a gray residue at the prop driver (#20-6101) to crankcase (#10-6102) interface. Perhaps the gray residue was from the two aluminum parts rubbing together, and the lockup/roughness was from heat expansion of the crankcase.
This engine was broke-in exactly as specified in the "Owner's Guide" for 5 tanks of fuel on a test stand, then had 5 more airborne tanks as specified. The problem didn't appear until the last tank. What is the solution to this problem? :?: