If it was in my driveway I would do a leak down test to get an idea of the leakage amount and then place full shop pressure in the cylinder to determine if it is a valve or piston problem and know which valve. Once you adjust stuff diagnostics become even more difficult. 

Dennis

-----Original Message----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of mark drillock
Sent: Saturday, May 24, 2014 1:34 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Engine Advice Needed

If it was in my driveway the test would now be to loosen the valve adjusters a full turn on that low reading cylinder. Then compression test that cyl again.

At this point I would pull the 1 plug, test the compression again to get a new base reading and since the other plugs are still in, then remove valve cover, loosen 1 adjuster for that cyl exactly 360 degrees. Test compression, loosen the other adjuster 360 degrees, test again. The reason for 360 degrees is that the adjusters get flat spots worn into them over time and a fraction of a turn loosening can actually bring a high spot into position and then the clearance is actually tighter rather than looser. Having 2 new adjustors on hand might be good too so you can replace the adjusters if mushroomed or pitted.

Mark

Loren Busch wrote:
> In a '90 Westy, stock 2.1L WBX with 185k miles, auto tranny
>
> Recent compression test is 150, 145, 135, 70.  Number one is 70.
> So, two questions.
> How long can I drive with this condition before I have major problems?
> And second, what is my best solution to this.
> BTW, oil pressure is good, 60 psi at idle warm.
>