Other things that can offer a false reading:

Low charge on battery
Failure to remove all spark plugs during test
Failure to depress clutch (so you aren't spinning the tranny junk as well)
Failure to open the throttle fully (so the motor can't suck in air)
Filthy air filter

Any or all of these can reduce your *apparent* compression. Also, make sure
the conditions are relatively the same from one test to another: motor
temp, oil viscosity, cleanliness of air filter, etc.

Cheers,

G. Matthew Bulley
Bulley-Hewlett
Corporate Communications Counselors
www.bulley-hewlett.com
Cary, NC USA
888.468.4880 tollfree

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-----Original Message-----
From:   Wagner, James W., , SAF/AQPS [SMTP:WagnerJW@PENTAGON.AF.MIL]
Sent:   Friday, December 10, 1999 2:44 PM
To:     vanagon@GERRY.VANAGON.COM
Subject:        Re: Shaft and compression

Maybe just stating the obvious, but:

The first time I did a compression test, I failed to let the engine turn
over an adequate number of times.  I ran the starter as I normally do when
starting the engine: just a couple engine revolutions.  I eventually
learned
it takes a few turns of the key to build the pressure up to 150 psi (my
current readings).  Also, I can only hand tighten my tester into the
cylinder, so I might have some loses there.

James Wagner
85 Vanagon Westy GL

> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf
> Of Joel D Shortlidge
> Sent: Friday, December 10, 1999 11:11 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Shaft and compression
>
>
> Hey Volks,
>         Well my brother got back the shaft for his Syncro
> from the drive line
> place!  It was balanced with washers and had new U-joints
> installed. It
> was $198 but it has a 90 day guarantee.
>         Also my brother tested the compression on his '87
> Syncro.  He followed
> all the directions for the tester and it read 90 psi, 90psi, 80,
> 84!!!!!!!  he got these same #'s three times!  No wonder it
> is so %#%$%#@
>  SLOW!!!  I can't belive it even RUNS!!!  The BIG book says between
> 184psi and 140 MIN!!  This engine block has 150,000 miles on
> it, it was
> rebuilt professionaly by a local VW guru 40,000 miles ago!
> It does not
> burn a drop of oil or coolant and starts and runs fine!  It
> just doesn't
> have any real power, but it will do 70 mph on a flat away.  So what do
> you think? valves? rings? bad reading?
>         I will e-mail once the shaft is installed.
>
> PS. E-mail me directly I am off the list right now!
>
> ___________________________________________________________________
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