Compression ratio

[SSpev]

Many people talk about what CR they have. Does anyone measure it? I do. Most that I talk to say I used the 11 pistons with factory heads. Or i figured from the factory specs. I found that this method is 0 to 1 point low. could be .5 point in one engine. The only way to know is measure it. I do. To get my 348 close to 9.5, I sorted rods and pistons to get the piston as high as possible. My average CR was 9.42 with a deviation of about .05. This is just memory as I still can't get to all my notes.

[Bungy]

Tom, of all the engines I have actually measured, none have been at the factory specs. All have been below. I think the factory figures were all calculated as well using the minimum acceptable combustion chamber and maximum piston height etc.

[walkerheaders]

http://www.348-409.com/forum/showthread.php?s=&threadid=1874

wasnt this just discussed last week?

[SSpev]

No, that tread was how to calculate with a formula. I asked if anyone ever accuately MEASURES the stuff. Then and only then can you KNOW what the CR is. Not "I got 11 to 1 pistons" Not "well the camber is 70 cc, valve releaf is 4 cc, gasket is about .040. That should be about 10 to 1...calculated...shoulden it?" :confused: ;) ;) :deal :deal :)

[walkerheaders]

my mistake, i actually do measure everything as you say and posted that on the other thread.same answer, different question.