The gap could have closed while the plug was bouncing around, I guess. I don't think it had been over tightened. I just do a little more than finger tighten. It's been a while since I changed the plugs. Like probably over a year. There was no aluminum on the plug. I think the head is stripped now though. :( I stuck a claw grabber thing in the cylinder and didn't feel anything in there. It was running fine. No knocking or anything.
Last edited by L200B; 06-04-2017 at 10:11 PM.