I have seen this fairly often. The 165 and 175 readings are the normal
ones. The low readings on cylinders 1 and 3 is probably caused by worn
cam lobes. The same lobes operate the opposing cylinders. A leak-down
test will more accurately determine if the valves or rings are leaking.
If the performance is acceptable, I wouldn't worry about the worn lobes.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Larry and Avery
Sent: Thursday, May 06, 2004 6:27 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Odd Compression Readings

Earlier this week I was at Frank Condelli's for some Spring Tune-Up. He
measured my compression as 130, 165, 125, 175 psi for cylinders 1 to 4.
This is an old engine with over 250,000 kms (about 155 K miles) with
original heads and gaskets. So we were quite surprised. Our conclusion
was that heavy deposits must have built up in cylinders 2 and 4. Why not
1 and 3 we don't know.

My question is: 'What is the best and safest way to reduce/remove these
deposits without removing the heads?'

At present, I switched to high octane fuel and have added a large slug
of Marvel Mystery Oil to the gas with a full fill. The hope is that the
Marvel will dissolve away the deposit over time. The high octane is
simply because the compression requires it.

Has anyone experienced this odd compression before? How did you reduce
it?
Thanks in advance
Larry

..........There are 10 kinds of people in this world. Those who can read
binary and those who cannot...........