Date:         Sat, 29 May 1999 19:40:56 EDT
Reply-To:     KENWILFY@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         KENWILFY@AOL.COM
Subject:      Update on piston problem (the death of a piston)
Content-Type: text/plain; charset="us-ascii"

OK I just wanted to update the list on my customer's problem with the broken
piston. To recap he had a VW factory rebuild installed two years ago (aprox
40k miles on it).  He came to me complaining of power loss and he had taken
it to another shop where they said that he had lost a cylinder.  Number three
cylinder was found to have no compression so I removed the head and found
that the piston itself had lost a large chunk of itself (much aluminum
shrapnel inside the cylinder and head).  I asked the list for suggestions as
to what could cause this and one person suggested detonation.  Well after
examining the motor further, I have decided that he was right.

When the garage installed this fellow's nice factory rebuild they neglected
to put a ground strap on the head.  So for the past two years his motor
hasn't run worth a lick.  It was constantly running rich because without that
ground strap the computer basically goes haywire.  I asked him about the
driveability of the van and he said it "ran fine" , oh yeah sometimes it
would "buck and also bog down".  This guy must be one of the most tolerant
customers in the world.  If I had paid over $3500 for a rebuilt engine and
installation and then the van didn't run right!  I would've been back there
in a second.  But not him.

So the basic scenerio is that for two years the van ran really rich all the
time.  Carbon built up in the cylinders.  Finally one day one of the thick
carbon deposits got so hot that it glowed red, and ignited the fuel mixture
too rapidly or at the wrong time (the first is detonation and the second is
preignition, both are bad for the motor).  This might have happened only once
or several times until it finally blew away part of the piston.  After losing
the cylinder the customer probably drove the van at least 50 miles to home
(probably more but that is all he will admit to).  When I drained the oil it
seemed like about 50% oil and 50% gas (all that unburnt fuel went right past
the piston into the crankcase).  So the motor is basically toast.  We are
getting a rebuilt one and I'm installing it.

So if you are having a bucking problem or you can tell your motor is running
rich (black smoke coming out the exhaust), don't ignore the problem.  If you
ignore your motor it will go away as this customer learned very painfully.  I
don't put all the blame on him though.  If the shop had done a thorough job
when they installed the motor initially (I found several other half tightened
bolts and some missing brackets on the motor) then this probably wouldn't
have happened either.

Moral:  Take good care of your engine and find a reliable shop to do whatever
work you can't/don't want to do.
Ken Wilford
Van-Again
John 3:16