Date: Thu, 26 Jan 2006 21:41:39 -0500
Reply-To: Benny boy <huotb@VIDEOTRON.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Benny boy <huotb@VIDEOTRON.CA>
Subject: Re: Compression Test
Theory, theory... he he he... on air-cool engine, #3 is somewhat the hotter
one, why!!! well, the oil cooler take is share of airflow, leaving the #3
(farther in front) with less air, also, the thermostat air-flap works
against the #3... Still, after 40k on mine, am 140psi all around, a bit high
on an aircool engine... he he he..
Your suggestion make sense, but the front part of the crank is well
suported, and crank are not a proplem on boxer! cam are, but mostly heads..
now, could the front cylinder have less coolant? Ask Larry Chase if he had
problemS with #1 and #3, it would be YES..... Bob as way more experience
that me in that matter....
What i can tell you for sure is that i have seen VERY good OEM front crank
seal go away in a short period of time!!!!!!!????????
I'm a re-sealer more than i am an engine rebuilt guy.... Bob knows way more...
The thing is when do you check compression? after 250k miles!!!!! now, is
that normal that some cylinder are a bit low! who care which one... boxer
are solid engine, with over 20 years of driving.... they leak, that is true,
but that is a classic VW problem!!! otherwise, they are pretty pretty good
engine, pushing a very heavy van when most other engine company would have
less success with the same engine displacement.
Cheers gentlemen's, Ben
http://www.benplace.com/vw2.htm
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okay you ready for my guess at why this has been the case on all the boxers
i have done a compression test on? i think it is due to the main bearings
near the flywheel getting beat out of round. the excess slop in the crank
allows (over time) the rods to move at a greater angle relative to the bore
thus wearing the rings on those two cylinders. this is part of the reason
that i suggest doing a line bore when ever you do a rebuild on a boxer.
now the question i have for all you old air cooled wrench types is... is the
same pattern of low compression in the two cylinders nearest the flywheel
the same as in the boxer? maybe we can even get a comment or two from boston
bob on the theory :).
jonathan
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