I don't recall hearing about any instances of spring steel being used for head bolts. Normally high tensile steel is used. However, for applications where the valve clearances increase as the engine warms up, spring steel would probably suffice. As would plasticine.
Steve
Spring steel is normally high tensile steel, either way the elastic modulus is the same & somewhat different to plasticines.
Excuse me? I quoted your entire reply.
OK, but being a liquid the vast majority would be easily forced out of the gap by the pressure of the valve spring, if the valve wasn't fully open. The remainder would presumably still be there when the engine is running (if slightly thinner when hot), so can be included when measuring the clearance.
But if there's absolutely no clearance to start with, and removing a 0.1mm shim makes the clearance somewhere in the region of 0.05mm, do you at least agree that it's reasonable to describe the clearance as -0.05mm, or, at the very least, negative?
Although specific application spring steel tends to have a higher carbon content than steel specifically manufactured for high tensile strength. But in any case, since we seem to have moved into a universe where A, a ford york engine can reverse the temperature vs expansion equation, and B, a ford york engine can be kept running long enough between head gasket changes to reach normal working temperature without self-destructing, it probably doesn't make much difference.
I still don't accept your premise of the valve clearance increasing with temperature.
Steve
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