93CobraR

Thanks again! I reached out to zKars, I’ll see what he has to say. Also, I wonder how much I could mill off the E31 cylinder head to help get the compression ratio back up before I ran into chain tensioner issues?

It’s a very low number, numbers matching, right hand drive car.

I appreciate the response, also I would be taking the block 1mm over to 79mm for the pistons above. I used a few different calculators and was getting in the mid to high 7’s and that’s what made me worried as well as potential valve clearance issues with the block using the E31 with the larger valves. I saw that Tony D had mentioned using L24 pistons in the L20 block but I’m guessing it would have to be sleeved? I think that would be my best way out if the block doesn’t need sleeved.

Hello all, long time lurker, first time posting. I have a L20A engine that I am currently rebuilding and I have some questions I am hoping someone can help me with since there’s not a lot of information on the earlier engines in the US. First, my problem is the original E30 cylinder head was missing and all I was able to obtain was the E31. It’s my understanding that the E30 had smaller valve(s) and a smaller combustion chamber. I think the E30 was 36-38cc and the E31 is 42.5? My second issue is, the original pistons were garbage, and I can’t seem to find factory replacements. I have been looking at the KAMEARI light weight street pistons (SP-L20401-79) that are 79mm. I understand that I would need to go to a full floating rod to utilize these. I was looking at the CXracing L24 rods which are 133mm long like the L20a rods. My questions are, possible valve interference with the engine block due to the small boar and the oversized E31 cylinder head valves. Next, low compression ratio due to the higher cc head and the new pistons. Any advice on this situation would be much appreciated. Links for the rods and pistons below: Pistons https://www.kameariengineworks.co.jp/4-catalogue/2024.8.7-English-cataloge-v4/E0011.pdf Connecting Rods https://www.cxracing.com/ROD-L6-1330x6?srsltid=AfmBOoq1seHAZKHRIzfi8Ty5q1oPRFdG1V-m7n75OsCHTH5WlRE-H_q4i8Y