compression ratio

[Paul Lennemann <pjlenn@xxxxxxxxx>]

I got one head pulled off of my motor today.  I was pretty disappointed 
in what I found.  My goal is to get the C.R. bumped up to @ 9.0:1 or a 
little better.  What I found was that my pistons are down in the hole at 
least .140".  Using the C.R calculator at:  
http://www.csgnetwork.com/compcalc.html

 I used 4.32" bore dia.
        3.75" stroke
        0.25 compressed head gasket thickness (a guess)
        4.40" Head gasket bore dia. (a guess)
        88 cc's for the chamber volume (906 heads)
         0 piston dome volume (flat top pistons)
         0.140 for piston deck clearance
This yields a C.R. of 8.04:1.  This was @ my guess for what I had.  But 
finding those pistons that far down in the hole was a bit of a bummer.  
I was hoping to be able to mill the heads a little to achieve the higher 
compression I was looking for but with the pistons down 0.140 I don't 
think that will get me where I want to be.
I'm guessing if I took 0.060" off the heads it would drop the chamber 
volume to @ 84 CC's.  That would only give me a bump of @ .23.  Not much 
bang for the buck.  So it looks like I'm going to have to go into this 
thing a lot deeper than I wanted to in order to meet my goals.

Paul L.
'63 Sport Fury
440/727
http://www.1962to1965mopar.ornocar.org/ml-lennemann63.html


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