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E21 for E12 Head Swap


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I am going to swap my E12 head for a E21 head. My engine is fitted with shallow piano topped pistons (about 3-4mm high). I think these are 8.5:1 compression ratio.

What do I need to grind off the new head for piston clearance and what will the typical compression ratio be afterward?

Thanks in advance

rtheriaque wrote:

Carbs: They're necessary and barely controlled fuel leaks that sometimes match the air passing through them.

My build blog:http://www.bmw2002faq.com/blog/163-simeons-blog/

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Put some plasticene across the top of the pistons, bolt head on without head gasket i just nip it down , connect cam chain , rotate engine by hand at least 360 deg,dont force it if you feel resistance,remove head ,plastacine will show you where.Now saying all that I have done the same at one stage E12 to E21 Low top pianos and Idont think I ground off much at all .....depending on your head thickness as well.Doing it without the head gasket will give you that bit more clearance when you put it back together with the gasket. You wouldnt notice the differance in comp ratio .

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