Probably a long time, but the "unbalance" will take its toll eventually.  You need to figure out if it's valve or rings causing the low compression.

Do the compression test again with a squirt of oil in each and see if the compression comes up.  If it does, the rings are worn, and if it doesn't it's a valve problem.  Check the lash.

A leak down test on all of the cylinders can also help pinpoint which valve(s) are leaking, or if the rings are leaking, or if everything is leaking. 

Be sure engine is fully warmed up, remove all the sparkplugs, and prop open the throttle to do the compression test.  Engine should spin free and fast. 

If the rings are good and given the oil pressure you have, you could replace the heads and probably get another 100K+ out of it. 

I think you have plenty of time to build up your engine fund though if the rings are shot.

It's up to you what to do at that point--rebuild or convert.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Loren Busch
Sent: Saturday, May 24, 2014 9:30 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Engine Advice Needed

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.