Thanks to these recordings--(http://www.ratwell.com/technical/EngineSounds.html)
I'm thinking I have valve problems, or lifter problems I should say

________________________________
From: Richard Jones <jones@colorado.edu>
To: beer_eighty@YAHOO.COM
Cc: Vanagon Mailing List <vanagon@gerry.vanagon.com>
Sent: Monday, June 1, 2009 6:54:13 PM
Subject: re: '82-2.0 teardown. help me find the knocking please

> A ticking progressed to a knocking my final trip of last summer.sounds like front end of the left side case.

I have an '81 air-cooled, non-California.  It ran too
hot around Bishop and Lone Pine one September and started
knocking.  I drove it home to Boulder.  Teardown
revealed the noise was piston slap.  The cylinders were
all scuffed up.

Cause:  poor sealing of the engine tin to the body, so
heat was coming up to mix with the cooling air, which
then didn't.

Good luck!

Richard