I believe you probably should drop everything and go get your lottery ticket right now. I'm guessing something being bent or otherwise deformed is the reason the plug keeps getting collision damage.
Yeah, I thought about that. Maybe a good sized piece of that piston got bashed into the piston by the plug.
But...why is it closing the gap only at RPM. That's what has me head scratching.
I've run my piston to head clearance and intake valve to piston clearance as close as .040 and turned it over 8k and neither hit anything unless you were gaining bearing clearance.
I've done .048 on aluminum rods and it cleaned the carbon off the piston but it never touched the head or the intake valve, and that was shifting at 8800.
The fact that it's RPM related is what is bothering me the most. The fact that the engine either failed a piston or swallowed something is relatively benign.
