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Head Questions

To: mgs@Autox.Team.Net
Subject: Head Questions
From: Chris Delling <>
Date: Thu, 04 Dec 1997 14:09:10 -0500
I am looking for some advice on potential head modifications.  In Peter
Burgess's book, "How to Powertune the MGB" he gives a formula for
calculating engine compression ratio, and the effects of shaving the head
on compression ratio.  You must know the displacement of the cylinder at
TDC, and BDC, as well as the displacement of the combustion chamber.  

I have an old style head - pre-smog.  Does anyone know the displacement of
the combustion chamber, or do I need to use a burette to measure it?  For
the cylinder, is it safe to assume that 1798 CC's (engine displacement)/4
is accurate, or do I need to be more precise?  How does on account for the
area above the top cylinder ring when the piston is at TDC?

Also, when modifying the head, how can one know how much can be safely
removed from the head without causing potential valve-to-piston contact?
Trying to determine how much CR increase I can obtain w/o changing pistons.
 This is an 18V engine with low compression pistons.  

Thanks in advance for the help.


Chris Delling

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