need help trying to figure out comp.ratio hears what i got.heads 101cc,pistons 22ccdome/.180heigth,piston to deck clearance .009, 4.124 bore,3.76 stroke

Originally posted by Carl's 67 SS:
need help trying to figure out comp.ratio hears what i got.heads 101cc,pistons 22ccdome/.180heigth,piston to deck clearance .009, 4.124 bore,3.76 stroke 10.04 with a .039 gasket :D
My compression ratio program takes into account piston top dia & ring depth so it will vary a bit from some of the on line stuff.

I come up with 10.47-1 with a quench of .045

Originally posted by bigjimzlll:
I come up with 10.47-1 with a quench of .045 Jim,
Don't think so with Carl's numbers unless it's past my bedtime or somethin :D

Originally posted by Wolfplace:
</font><blockquote>quote:</font><hr />Originally posted by bigjimzlll:
I come up with 10.47-1 with a quench of .045 Jim,
Don't think so with Carl's numbers unless it's past my bedtime or somethin :D </font>[/QUOTE]It must of been past my bed time...lol I recalculated using a 4.2x.039 head gasket and came up with 10.16-1. This will give a quench of .054...with a .030 gasket I get 10.38-1 and a quench of .039...but I cant figure with the top of piston and ring depth.

Mike would you figure mine:
4.155x3.75
deck height is .004
head gasket is 4.2x.039
chamber is 54cc
V/R is 5cc

Jim,
13.02 :D
Assuming 4.125 piston head dia & rings .250 down

Edit--- using 4.200 as a gasket dia instead of 4.155 it's 12.98

Hey,,, it's early in the am for me graemlins/clonk.gif

Here is a little math lesson.Compression Ratio is Volume BDC/ Volume TDC.
For example:
V(BDC)=Stroke Volume+Head Gasket Volume+Deck Height Volume+Combustion Chamber Volume+Piston Volume
V(BDC)=(PI*((4.124/2)^2)*3.76)+(PI*(Head Gasket Bore/2)^2*Head Gasket Thickness)+(PI*((4.124/2)^2)*0.009)+(101cc*0.0610237)+(-22*0.0610237)
V(TDC)=Head Gasket Volume+Deck Height Volume+Combustion Chamber Volume+Piston Volume
V(TDC)=PI*(Head Gasket Bore/2)^2*Head Gasket Thickness)+(PI*((4.124/2)^2)*0.009)+(101cc*0.0610237)+(-22*0.0610237)
This being shown, it depends on what head gasket you use. The 0.0610237 is the conversion factor from cc's to cubic inches.
Another method is Ross Piston's Calculator
http://www.rosspistons.com/CR%20Calculator.htm

If you are going to go to the trouble of running it to 7 decimal places than you need to take into account the dia of the piston head & the distance the rings are from the top of the piston & the actual bore of the gasket,,, it all accounts for combustion space
I know,,,,picky, picky, picky ;)