c20let head sunk in between com. chambers?!

[c20let-matt]

my c20let was burning some coolant at first it was nearly unnoticeable but by time it became like a smoke machine!. When I removed the spark plug there was a little water on piston 3 and therefore had to remove the head. Also found water in the inlet manifold port 3 and exhaust manifold. the gasket had a small visible leak near piston 3 and also found out that between all 4 combustion chambers the head had sunk in by about 1mm. the engine never overheated or anything, the head is skimmed to a point where the inlet valves are level with the head's face, had to skim it due to pitting before installing. also the block has steel rings around the bores so a standard gasket is used.
The only thing I can think of is that the head was to thin and therefore it wasn't able to take the stress of the tightening torque

Any ideas, the picture is of the head before fitting just marked from where it sunk in, seems that in those points there are the water ways.

thaanks

[Nemesis]

Either way it's scrap now so just buy another head and bin that one!

[c20let-matt]

Either way it's scrap now so just buy another head and bin that one!

yes, I already have another head ready to bolt on, just wanted to know the possible cause so not to ruin another head.

[Pantera]

Its detonation, i have seen another car that melted pistons slightly do that, the pistons weren't that bad, the bore was perfect but the head was same like yours, head was welded up then skimmed and engine rebuilt and retuned and has been drving ever since

[steveboyslim]

my c20let was burning some coolant at first it was nearly unnoticeable but by time it became like a smoke machine!. When I removed the spark plug there was a little water on piston 3 and therefore had to remove the head. Also found water in the inlet manifold port 3 and exhaust manifold. the gasket had a small visible leak near piston 3 and also found out that between all 4 combustion chambers the head had sunk in by about 1mm. the engine never overheated or anything, the head is skimmed to a point where the inlet valves are level with the head's face, had to skim it due to pitting before installing. also the block has steel rings around the bores so a standard gasket is used.
The only thing I can think of is that the head was to thin and therefore it wasn't able to take the stress of the tightening torque

Any ideas, the picture is of the head before fitting just marked from where it sunk in, seems that in those points there are the water ways.

thaanks

If you fitted that head in that condition it was scrap before you started.

Steve

[c20let-matt]

I think it wasn't detonation as all plugs were good ..and it would sound that it's having detonation, also the pistons and bores are all fine.

Yes, steve I was expecting a short lifetime from that head but not that short, I couldn't skim a lot from it as it was already very low.

[steveboyslim]

I think it wasn't detonation as all plugs were good ..and it would sound that it's having detonation, also the pistons and bores are all fine.

Yes, steve I was expecting a short lifetime from that head but not that short, I couldn't skim a lot from it as it was already very low.

That is the trouble that head has been skimmed too much and in your case building a high horse power engine, will have weaken the head.
That head should not be used.
Also if that head had been on an engine which had suffered from deternation the aluminium will be soft.

Steve

[c20let-matt]

Thanks a lot for your help, I just wanted to know the cause so not to damage another head. the one I have now is like brand new, installed new seals, emptied tappits, and ground the valves and a light skim. (least possible). Will install a new payen std gasket as I have the piano wire in the block.

The other head failed under very low stress as the comp ratio is only 8:1 and had only 6psi of boost comp test gave about 130psi on all 4 ..just finished my running in ... from the beginning it had a little white smoke but I though it was only condensation which is good if not too much. After a few weeks it was increasing and when it was on the dyno it was smoking really bad after the 6th run.

Thanks again hope it will be fine