Fabian
Well-Known Member
Jaguar is on the money
I've tried various high compression cylinder heads and i've had metal to metal interference on all of them with anything up to 3 head gaskets. One cylinder head required 4 head gaskets to clear an NGK B6HS spark plug.
The other thing to note is that the cylinder head will walk around on the cylinder and find it's natural position if your engine uses 6mm head studs and 8mm stud holes in the cylinder and cylinder head.
Sometimes the natural position of the cylinder head is offset from the cylinder and because of this the cylinder head combustion chamber will walk it's way into contact with the piston, initially making a sound like detonation then an ever increasing metal to metal rattling sound, even if using 3 or 4 head gaskets.
Placing 6mm to 8mm sleeves over the 6mm head studs fixes the problem.
In such a situation you start chasing an ignition/compression problems because it sounds like detonation. I have wasted countless hours of my life doing this very thing, only to find out the real cause of the problem.
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