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Re: Compression Test

To: Bob Palmer <rpalmer@ames.ucsd.edu>
Subject: Re: Compression Test
From: Steve Laifman <laifman@flash.net>
Date: Wed, 18 Aug 1999 07:36:45 -0700
Bob,

While I've never tried a cold vs hot compression test (how did you ever get
cylinder 8 without burning something?), there are practical reasons for the
differences.

Thermal expansion, while hot, can close clearances, as the aluminum piston 
expands
more than the iron bores.  The valves can seat better when warmed up.  And 
perhaps
most importantly, the friction has been reduced from a cold crank so that the
cranking rpm is higher, giving higher readings.


Have you tried this test before and after an oil squirt in the spark plug holes
(two more burned knuckles.)

Steve

--
Steve Laifman         < Find out what is most     >
B9472289              < important in your life    >
                      < and don't let it get away!>

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