Combustion chamber volumes?

[Pancake]

Anyone have the combustion chamber volumes for the various M10 heads? I tried searching both the forums and google (and E30tech) but didn't find anything. I'm looking for the E21 head casting and the 1.8 head but would also love info on the E12 (got a couple in the back of my garage).

[MrNvgtr]

I just had my E12 head CC'd at 54.5. I'm not sure if that's the exact same figure as combustion chamber volume, but it sounds like what you're looking for. FYI, you probably want a few answers because I can't guarantee my E12 head chambers weren't changed much from a recent light polishing.

[Caesar]

take a look here

http://www.kengineering.info/cylinder%20head.html

[Pancake]

8cc difference between the E12 and 1.8 head... wow. I'll bet it's actually even closer to 10, since that head had been milled twice and a 64cc combustion chamber keeps creeping into my head from my E30 318 days.. How close to the E12 is the early (76) E21 head? I know the 1.8 is the most open, with a open semi-hemi design instead of quench pads.

I'm trying to figure compression on the 82 1.8 shortblock and 76 E21 top end I've got (from a previous owner). I didn't even think that it would work, but some people have suggested that the 8.8:1 pistons from the 80-82 E21 1.8 will while the 9.4:1 from the 83 and E30 won't. I'm getting the sneaking hunch I need to stop running 87 octane and bump my timing back up.