Date: Tue, 21 May 2002 14:53:02 -0400
Reply-To: Ben huot <huotx@VIDEOTRON.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ben huot <huotx@VIDEOTRON.CA>
Subject: Re: 84 update/head job
Tim, while the head is (are) out, if possible, have the heads tested by any
good engine rebuild shop. They can do a leak test. It can tell you how deep
(if it's leaking air) is the crack and if it can be repaired. At the same
time, valves should be removed and valve guide should be check for proper
clearance. Valve seal should also be replaced. This is the minimum safe
amount of work to do when a head is out.
Here are all the things you should do to put a head back in shape (if the
crack can be repaired)and if the rst of the engine is in good shape.
- Head-mating surface done (remove a few thousand of an inch) get rid of
the pitting.
- Valve seat done
- Valve mating surface cut.
- Valve guide properly check by someone competent.
- Valve spring check for proper compression.
- Camshaft check for wear and proper clearance.
- Rocker check for excessive wear.
WARNING, doing so imply an increase in compression, that is not always
good!!!!!!! The low part of the engine; pistons, rings, connecting rods are
subject to an increase in compression and are subject to future failure if
only the top end is done. Especially for the piston ring and connecting
rod. Doing an overall of the top engine section should be followed by at
least a double check of the pistons-cylinder clearance and for sure a
complete set of new rings for all pistons. My engine had a 145psi -+ 3 in
all cylinders before I did this job (this is good). Only the top end was
done.
The wear of an engine is normally well distributed throughout the engine,
rebuilding only one section if the rest is worn out or getting old is not a
good idea.
My experience is from Honda engine, I don't think that the VW flat-4 is as
strong as any Honda engine. We have done many complete heads rebuild on old
engine without doing anything to the lower parts with plenty of success. I
would not do the same for a low compression Vanagon engine.
A broken stud in the head is nothing (I broke all 8 on my heads), when head
is remove it is very easy to get the rest of the bolt out. If you cannot
get the bolt out yourself, bring this one to the engine rebuilt shop.
Good luck, Ben
http://www3.sympatico.ca/huotx/engine1.htm