# Advanced Engineering Tech - cr help!!! .200"x4.04 equals how many cc's?

4SFEDZ
05-22-2010, 08:50 PM
ok, im doin a rebuild and need help on figuring my cr! i have a 4.04 bore, 58cc heads, 3.75 stroke (385 ci) and flat top pistons, no valve release, and my piston at tdc is .200 in the hole! so if i could figure out how many cc's .200" with a 4.04 bore is i could use that figure as my valve relief and figure my cr with a certain head gasket thickness. does this make sense? lol!

NemeSS
05-22-2010, 09:13 PM
.200 in the bore doesnt sound right. 0_o
what is bore and compressed thickness of gaskets used?

4SFEDZ
05-22-2010, 10:19 PM
.200 in the bore doesnt sound right. 0_o
what is bore and compressed thickness of gaskets used?

bore is 4.04, not sure on gasket, trying to see what thickness to use. this is not an ls motor

NemeSS
05-22-2010, 10:32 PM
sound like sbc/lt type build
ur gonna prolly want to run as thin as possible gasket with piston being that deep bore in the hole.
i have always like to kept 0 deck for sbc/lt at least.
and always minimum
+.010 protruding for ls motors
what gasket u plan on running? its not gonna be same as bore of block. has to be bigger.
assuming u were using a theoretical 4.125 bore by .030 compressed gasket: the above engine specs out to around 8.39:1 scr

4SFEDZ
05-22-2010, 10:33 PM
ok i think im on the right track,

cylinder volume, http://www.online-calculators.co.uk/volumetric/cylindervolume.php

convert cubis inches to cc's, http://wiki.answers.com/Q/How_many_cubic_inches_are_in_1000_cc

NemeSS
05-22-2010, 10:35 PM
the piston being that deep in the bore at tdc may affect quench distance.
i like to keep quench in engines ive put together around .035-.040 at least for all builds from n/a to psi
but thats just me

4SFEDZ
05-22-2010, 11:01 PM
ok i found this

http://www.csgnetwork.com/compcalc.html

and yea that was my next question, i prolly need to go as thin on a gasket as possible, what the thinest i should go? and yes its a lt build. im plannin on runnin 20+psi of boost,and race gas. im not to familiar with quench!

NemeSS
05-22-2010, 11:08 PM
the above calculator is pretty accurate. same numbers i got. i figure my scr and dcr by hand with sheet of paper and calculator. i also figure rod/stroke ratio, quench, amount to mill heads, dcr if have cam card etc. i havent found online calc. yet that has all those features.

4SFEDZ
05-22-2010, 11:17 PM
hmm, thanks for the replies, what gasket you recommend? felpro or cometic? also would there be any disadvantage of running the thinnest gasket possible? i just need to figure out my piston to valve!

NemeSS
05-22-2010, 11:27 PM
prolly thnnest mls u can get. bore doesnt really matter as long as its bigger than 4.04. i dont think u will have too many ptv clearance issues with the piston being that far away at tdc. lol
i always keep at .100 minimum for ptv clearance for both valves
.200 is dam way in there. i dont think ive ever heard anyone going with the piston that deep in the bore.

mwg2600
05-23-2010, 03:41 PM
It sounds like you have the wrong rods.

Wicked94Z
05-27-2010, 06:15 AM
yea running a 6" rod piston on a 5.7" rod? that's the only way i see this happening...

KCS
05-27-2010, 09:25 AM
20psi? It'll be fine. For some reason, boosted engines don't really like quench. They tend to make power when you run quench REALLY loose, but I don't. .200" sounds excessive, but I don't think it'll hurt anything.

Got any part numbers on your piston/rod combo?

bww3588
06-01-2010, 08:48 AM
.200 in the hole is beyond unexceptable. with your 58 cc heads, your going to have a 92cc's above the piston @TDC without the gasket....with the excessive quench volume, that flame is going to be so weak, even under boost.

KCS
06-01-2010, 11:33 AM
.200 in the hole is beyond unexceptable. with your 58 cc heads, your going to have a 92cc's above the piston @TDC without the gasket....with the excessive quench volume, that flame is going to be so weak, even under boost.

That's the point. Heavily boosted engines typically don't like quench. I agree that .200" is a lot, but what I'm saying is that I don't think it's going to hurt anything since he is planning on 20psi and race gas.

NemeSS
06-01-2010, 01:21 PM
:corn: