Found this when I removed my cylinder head...

[e30gumball]

that was caused by a spark plug breaking off the tip.
I have seen exactly the same, it bounces off the top of the piston and smashes the soft hot aluminium of the head.
it would be worth polishing it out (as well as the other 5) and using it as a race head.

[Jand3rson]

that was caused by a spark plug breaking off the tip.
I have seen exactly the same, it bounces off the top of the piston and smashes the soft hot aluminium of the head.

That's exactly what I was thinking. The top of that piston of that cylinder had the same damage on that side.

[e30gumball]

The reason i am so sure is that the broke end normally bounces up on the same side held into a part of the chamber by the piston skirt hence the damage to a certain area instead of the whole area.

It probably burned up after a while as it loses its toughness after breaking from the plug arm above the electrode.

[M-technik-3]

The term is FOD ala Foreign Object Debris

[Jand3rson]

My brother in law repaired the damage today. Sorry I can't get you guys a pic, it's already boxed up and ready to ship. We smoothed it all out with a Dremel to a very nice finish. It should have no problems at all, almost all of the damage is completely non-existent. It really came out good.

[e30gumball]

did you match all 6 of the dishes or just the damaged 1 ?

[Jand3rson]

did you match all 6 of the dishes or just the damaged 1 ?

We made sure it matched against the others.

I wish I could get a pic, but there's no way I'm opeing THAT box up again. It's sealed up tighter than a duck's butt.