Our TiiCo has been resonance free for a  few months now.  My search is over.
She's smooth as the 2.0 16V in my Jetta.

FWIW, my opinion now is that there are several areas of the TiiCo engine
that participate sympathetically in the vibration problem.  I can't tell you
which is the biggest culprit; I failed to use a proper scientific method.  I
just threw ideas at it to see what would stick.  I still think that the
exhaust is a symptom not a cause.  My "pipe filled with sand" is now a the
head of a 5 lb sledge bolted to the header just before it turns to cross the
rear of the van.  This does help; when I remove it, some noise returns.  I
used "B-Quiet Beavertail" sound deadening extensively throughout the rear of
our Vanagon.  I filled all of the voids in the motor & tranny mounts with
very dense foam from a boat bumper.  It's jammed in with the mount opened up
then released. We continue to use the flexi-mount on the alternator (if you
do this, be sure the lower pivot is loose enough to move.  If it's rigid you
defeat the the whole idea).  These mods together defeated the drone.

Gary
----- Original Message -----
From: "phil stanhope" <napszeerf@YAHOO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, April 24, 2002 2:12 PM
Subject: Re: Tiico: Harmonic balancing pulley

> "I think it was Gary Stearns that posted a few
> messages outlining his
> experiences with vibrations and some solutions."
>
> Yeah he did, here is a something he posted a few
> months ago,(i keep a private file of good tips) check
> the snip:
>