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Subject: Re: What's normal comp 4 TR6

To: "6pack-digest@autox.team.net" <6pack-digest@autox.team.net>,
Subject: Subject: Re: What's normal comp 4 TR6
From: Robert Greene <rgreene@whoi.edu>
Date: Wed, 24 Oct 2001 21:00:09 -0400
Hi Dick & Shane:
    For what is worth. I have a stock 76 tr6. (no mods that I know of)
My last comp. test showed 147 +- 3# across the board.
    Bob Greene
76 Tr6 CF56728UO.
Cape Cod British Car club
http//clubs.hemmings.com/capecodbritish/
F
<From: tr6taylor@webtv.net (Sally or Dick Taylor)
    Hi, Shane---As you know, a compression test measures pressure, and
while
it's related to the compression ratio, the two are different. It's
possible to have a high CR and not have high pressure. A lot depends on
the type of cam shaft used and to some degree, how the cam is timed. In
any case, a compression test measures the air trapped between the piston

top and the combustion chamber. Under most circumstances, a low
compressioned head will give back lower pressure readings. I just
measured fellow owner J. Lopez' 1974, recently overhauled engine. Stock
head at 3.580. It showed 120 lb. with a performance cam. After
installing a stock cam, (long story) the pressure rose to 125 lb,
indicating the performance cam bled off some of the pressure before both

valves closed.

In short, I don't think there are many stock '74's that have a CR as
high as yours. It would be interesting for others with the late (stock)
head to give feed back on this.

Listers?

Dick Taylor>

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