Date:         Mon, 7 Apr 2008 14:06:12 -0400
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: 1985 Vanagon Gas Eng. - Block's stud failure - details
              acoming....
Comments: To: word_aag@COMCAST.NET
In-Reply-To:  <007301c898c9$c0a7a5c0$6601a8c0@WordHomePC>
Content-Type: text/plain; format=flowed

I made a typo. # 5 should read "Not" honing the cylinders. You have worn
piston skirts and worn cylinders. Honing will increase the clearance
further. You need to make some carefull measurements.

Nuts should rarley be reused on critical applications. ~97% of the load is
carried on the bottom three threads resulting in some distortion. This will
effect the pre-load or tension of the assembly for a given torque. Using a
die on the stud and tap on the nut will effect the class of thread fit. The
stud threads are rolled, not cut.

Visable corroision on the studs is sure sign repalcement is needed. Not only
can the corroision weaken the studs due to missing material, the corroision
creates stress risers. Think of scoring glass to cut it. The corroison on
the studs also means your coolant was not able to do its job. Most likely
bubbles formed and the vibration of the studs caused cavitation eroision.
This is a common Diesel problem.

Dennis


>From: AAG - Larry Word <word_aag@COMCAST.NET>
>Reply-To: AAG - Larry Word <word_aag@COMCAST.NET>
>To: vanagon@GERRY.VANAGON.COM
>Subject: 1985 Vanagon Gas Eng. - Block's stud failure - details acoming....
>Date: Mon, 7 Apr 2008 12:09:26 -0400
>
>Group's advise thus far: (1) determine true cause of stud failure - Either
>heat or corroision or pre-load issues would likely indicate changing the
>full set.
>
>                                     (2) Always replace the stud cap nuts -
>the nut you torque to "set head gasket"....WHY always replace?  The studs
>have visible corrison.
>
>                                     (3) Piston rings really do not wear -
>they loose tension, break, get stuck etc.
>
>                                     (4) Piston wear is most likely to
>occur in the ring lands on the pistons.
>
>                                     (5) If you're replacing the rings you
>probably should hone cylinders trying to avoid piston slap - Can anyone
>explain this further?
>(6) New rings will set within old cylinder jugs, even without honing  - Can
>anyone attest to this fact(s)? Tells of what you did?
>
>                                     (7) Takes time to properly hone
>cylinders, else better off adding a new set of cylinders - at that point
>you should do both sides of engine.
>
>
>
>Is there a trick to (a) removing the wrist pins that hold pistons to rod in
>this Vanagon engine - I've done aircooled engine but never Vanagon's?
>
>                             (b) re-installing the new ring set (3 rings in
>my case) onto the old pistons
>
>                                     -Art of inspecting and clean the ring
>lands on the piston - PLEASE ADVISE!
>
>
>
>Sorry to "scream" but I really don't want to get this wrong - Thanks in
>advance for group's collective wisdom, I'm always impressed....
>
>
>
>Have a good day!
>
>Larry Word
>Ga.