It focused on the thread and not the porcelain, how is the piston, did it take that out too?
I have never pushed it that far with my own stuff, I'm still on pump gas.
I've seen a lot of it with friends stuff though, sometimes it takes the piston out too, sometimes the ground strap is gone and everything else is fine. I've even seen a large chunk of the cylinder wall melted out, but not all the way through, strange. The worst is when the block, crank, cam, and rods are all in chunks all over the place.