the detonation on the head button doesn't lie....... the bushing came out from the engine being too lean.....The bushing and crankpin lost lubrication causing the bushing to stick onto the crankpin and spinning out of the rod....with a rod bushing out an engine wont even run, let alone run long enough to cause detonation marks on the button.......This is definitely a case of an engine being run too lean...detonated head button and a spun rod bushing....this one is as cut and dry as they get I am sorry to say...