Howdy
Gasket went on a 999 FIRE. Took off the head, no warps, or damage. The head bolts were bolted down unbelievably tight. Way way tighter than the specified torque. The gasket was broken (wire bit) on cylinder 4. However piston 3 has damage to the outside edge, and correspondingly, on the cylinder wall at the top were deposited/stuck hard, non-magnetic shards, almost matching the damage in the piston. My question is, are these from the cylinder seizing at some point and the bits breaking off the piston, or are they broken rings. I am not sure how the car was running before it overheated, so don't know what the compresion was on this cylinder. Is there any way of knowing what it is, and should I just put the lot back together with a new gasket and see how it goes?

Just replace the engine. 999cc FIREs are easy to come by, even in NZ.

Yeah, a replacement is definately on the cards. The engines not worth working on. Had a look at the piston. Rings are all there, so not sure what caused this. Anyway, in the bin it goes.

Bloody hell - that's stuffed!

It is an interesting question. Maybe something was dropped into the inlet manifold (during work on the carburettor) but it's a strange erosion. I think your idea was more likely - the engine overheated severely and the piston started to weld itself to the bore, losing chunks in the process.

The engine may have continued to work all right, but as jjhepburn says, I think for the trouble you've gone to so far, it was best to change it. Apart from anything else, rings lose their springiness when overheated, so they would have needed replacing/cylinders honing.

-Alex

Re: Piston damage, what has caused this?

Yeah, definately overheating and welding. It ran for a while with the piston like this, until it ran out of water again and the gasket blew apart. I think the head was cranked down super hard in an attempt by a 'mechanic' who charged (not me) $1400 to fix the rough idle problem.

Glad I didn't waste a new gasket on it.