Date:         Fri, 26 Jul 1996 18:46:26 -0700
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         natasha!kombi@adobe.mv.us.adobe.com
Subject:      Re: GEX update (fwd)


> 
> I just returned from the garage and hada look at the head in question. The
> intake vlave seat on number was not dropped or dislodged by pushed
> in a fraction. There was exhaust etc from where the head was not meeting
> the cylinder. Any one familiar with this one?
> 
This problem sounds like failure due to pre-ignition (knocking, pinging,
etc.).  Also check for damage on the piston crown.  VW buses have their
engines rather far from the ears of their drivers, pull large loads with 
itty-bitty engines, heat up alot, etc. alltogether a bad mixture for this.
The pinging occurs when the mixture explodes rather than burns.  It sounds
like a rather tinkly rattling under load (like going up hills).  If you
don't stop what you're doing (downshift, take the foot off the gas) you
continue to hammer the inside of the engine.  On most engines, the piston
crown, being aluminum is the weak point, and you blow a hole in the piston.
Veedubs break in other formats, including driving a valve through the head.

I've never done this particular variation, but I got an '81 Vanagon that
has *just* this problem -- I'm parting it out (not for this reason, tho --
it's really trashed!).  The exhaust valve is pushed about 1/2" into the head.

On a single cylinder, I would expect this to be caused by too lean a mixture,
either from a leak in the intake or a bad injector.  If this is merely the
worst cylinder of four with similar problems, then I'd suspect driver error.
Pinging *can* result from too high compression (145 sounds too high to me --
any comments out there?) or from a hot spot in the cylinder -- a sharp edge
like a spark plug thread can do this (or the crud build-up in old engines).

Regardless, if the engine was damaged by knocking, I would not expect this
to be anybody's fault other than your own.  The head may have been bad,
and broken under the exhaust seat, so maybe I'm wrong -- I hope so.

On my ol' single cab, not only was the engine far away, but there was no
van body channeling the sound.  I trashed lots of engines in that thing.
Cost of doin' business -- couldn't hear a thing.

Good luck -- I hope I'm wrong, and am not expert on this...

malcolm