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Deck Height and compression ratio
Posted: Fri Jun 30, 2006 6:03 am
by JohnBC
I am building one of Jake's 2270s. As you know he is off on a well deserved holiday. Unfortunately I figured out my deck height one day too late! Here is what I have: 58 cc chambers, flat pistons and 0.80 (2 mm) deck height. This gives me a compression ratio of 8.9:1.
What should I be aming for with a street engine on pump gas? More like 9.2:1 ish?
Posted: Fri Jun 30, 2006 7:02 am
by JohnBC
Cam number is 163/86b and it is going into a 914.
Posted: Fri Jun 30, 2006 11:10 am
by Dean
Hi John,
Sorry I can't help you with your question on what the compression ratio should be but I do have a question for you. Do the heads you got have a step in them and was the cc's written on the head include that step? I was looking at the Hotvw article on the torquer and it seems that the step is not included in the cc measurement. I'm going to try and cc the heads this weekend to find out but I don't have a bore plate that will fit so it's not going to be very accurate.
Posted: Fri Jun 30, 2006 6:16 pm
by JohnBC
Did a bit more digging and found Jake's recommenmdation was 0.055" which works out to about 9.3:1. I was able to work the shims I had to hit 0.050", about 9.4:1 which should be ducky.
My heads are from Len and the combustion chamber volume was stamped on the back. No step but they are not VW castings.