Originally Posted by
bigdel
My sons Focus was running 480hp when an ITV27 decided to disintegrate resulting in a melted piston. When we took it back to the engine builder, who builds all kinds of engines for road and track, he advised going back to the standard Ford plugs when the engine is rebuilt.
Or more likely...poor tuning, lean mixtures, detonation....destroyed the piston and the plug. Not that the plug caused it.