OEM Head gasket thickness


Staff member
The last time I rebuilt my engine I assumed the OEM head gasket compressed to a 1.2mm thickness. I think this was because HKS etc were selling 1.2mm as the "standard" replacement gasket

Reading around the internet on SR20DET rather than gtir, nowadays 1.1mm seems to be what people consider OEM compressed thickness.

This explains why Cosworth sell a 1.1mm gasket as their starting point rather than a 1.2mm. I expect the 1.2mm HKS sell is to compensate for the cleaning up of block/head surfaces prior to fitting a metal gasket?

I know I'm sweating the details here but my objective is to double check what is the OEM compressed thickness so when I deck the block and fit a larger HG I keep the size and shape of the combustion chamber as close to standard as possible.

I have adjustable cam timing but this will also help keep the cam timing as close to stock as possible.
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