Date:         Fri, 14 Jun 1996 17:20:18 -0700 (PDT)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Dwight Mattix<dmattix@qualcomm.com> (Dwight Mattix)
Subject:      (can do) Aluminum Crank Case..Weld or Replace?

used to have a lot of cases welded when i worked as an A&P on general
aviaton type engines (lycoming, continental, et al).  had success w/ some
extreme failures in aircraft powerplants. like when a jug would blow off
taking a section of the case w/ it.

would use Nixon's in LA area.  FAA approved.  Gotta be good enough for VW
too.  been 10 - 15 years. don't know if they're still there or how to
contact.  any good heliarc guy should be up to it.

also did w/ cracked motorcycle cases when chain would come off and bust a
chunk out. weld it up and mill out seal/bearing seats as needed.

on one hand, it'd be a cool experiment for you, but, might cost you to a
bit for a good welder to do it right.  my recollection is that doing it
right means heat treating for stress relief.

actually, i think more accurate term is that annealing is what you'd want
-- oven you can do this yourself good enough for gov work if you've an
available stink_up_able oven.  heat it up ~500F (my swag) in an oil bath,
hold it there 24 hrs., turn oven off and let it cool in it's own sweet
time.  the slower ramp down, the better.  probably some materials guy out
there who can tell me why i'm nuts/off the mark, but that's my recollection
of what worked/was judged airworthy.

i'd be tempted to try it, but that takes into account a certain propeller
head quotient.  what's the risk?  it ends up leaking again?

on the other hand a good VW case isn't _that_ expensive and is an
opportunity to convert/try hydraulic lifters for a little extra denaro.

in a $erious pinch?  never underestimate the ability of JB Weld.
i put many years, miles, trips down the strip on my T3 w/ JB weld repaired
tranny nose cone with no problems.  Musta been in 30 pieces before
reconstruction w/ epoxy.  granted that probably wasn't as severe duty as
your engine case.  only thing in your case, epoxy wouldn't do anything if
the crack wanted to propogate further.

my $.02,
dwight


>Bob is right.  I have never had to weld an aluminum case, but I've had a
>lot of other alum parts welded, like cylinder heads, without problems.  My
>personal VW-engine-rebuilding-bible, Tom Wilson's "How to Rebuild your Air
>Cooled VW" states very clearly that welding cracked cases is no problem.
>
>Here's some more friendly advice:  You shouldn't even be attempting this
>job without getting and reading a copy of the above book.
>
>-David