This usually caused by a bad seal between the head and the cylinders or a
leak in the exhaust system.  On these engines, I often find the case is
warped or worn on the center bearing web. This causes the cylinders to no
sit parallel.  Without the cylinders sitting perfectly square to each other,
the gaskets will not seal causing all sorts of problems.

Dennis

-----Original Message-----
From: Brian W. Block <bwb@MICRON.NET>
To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Date: Thursday, July 15, 1999 1:56 PM
Subject: backfiring..

>Hello all--
>
>Any hints or suggestions on this one?  I've done a top end rebuild on the
>83 van (air-cooled) and now it seems to be running o.k, but Im experiencing
>excessive backfiring (the van, not myself)  Its not real loud, but just
>noticeable when you let off the gas.
>What could cause this?  I'm stumped.
>
>
>Regards,
>
>Brian