Michael,
Compression is measured per cylinder. Not as a combined pressure. The 180
psi is + or - 10 psi. 90 psi is way too low. A low compression is caused by
worn (or broken) rings or bad valves.
A good test to run on a low pressure cylinder is to squirt some oil in the
hole and crank the engine about three rotations, a bad valve will show
little to no difference with compression where as a worn ring will tend to
pump up the compression.
This may be more than you wanted to know but I though I might as well share.
Charlie Hubbard
1964 SPL310
-----Original Message-----
From: Mikie2U@aol.com [mailto:Mikie2U@aol.com]
Sent: Friday, August 20, 1999 11:59 AM
To: datsun-roadsters@autox.team.net
Subject: An Observation on Compression
I have a question/observation for the Roadster enthusiasts.
I am going to try to rebuild the engine for the 1600 that siezed up last
winter and while I was doing some reading to help me prep for the project I
made an observation and I want to ask if my reasoning is sound.
According to the specifications in the manual the compression pressure is
180.6 psi. If you divide that by 2 you come up with 90.3 psi. +/- a little
of that 90.3 should be considered a good compression reading, shouldn't it?
I base this assumption on 2 pistons being up while 2 are down, therefore the
180.6 / 2.
Or, do I have it all wrong?
By the way, Chris, my son opted to buy a nice '67 Mustang this summer, so I
get to have the Roadster.
Michael
'67 1600
Va Bch, VA
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