Date:         Tue, 14 Mar 2000 14:59:07 -0500
Reply-To:     John Anderson <jander14@WVU.EDU>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Anderson <jander14@WVU.EDU>
Subject:      Re: How best to JB weld pitted heads?
In-Reply-To:  <LPBBJDPNOOKKNECCKCKBEELMCBAA.jliasse@toast.net>
Content-Type: text/plain; charset="us-ascii"

>   First thing I did was to make VERY sure everything was CLEAN and oil
>free. Easiest way to do this is with a good carb cleaner and a wire brush.
>Get all that crud out of the pits so the JB will hold. Pick it out with a
>needle if necessary.

I'm going to comment here as well, as I've done quite a few sets and have
some in service now for 75k miles and 4-5 years or so.

Firstly you should really bead blast the surfaces, you can not begin to
imagine how extensive that corrosion actually is.  I've picked at it with
needles too, and Dremel tool wire brushed out what I though were massive
pits, then gone back with the bead blaster only to find massive swiss cheese
underneath all of the what I thought was cleaned out.  A rule of thumb I'd
say is that the corrosion is about 3 times worse than what it looks after you
clean it out by hand.  Plus using a dremel and brush or whatever tends to
only polish and smear aluminum, using the beadblaster will leave a nice
surface with plenty of "tooth" for the glue to grab.  Again from years of
glueing
on tabs to composite test samples, the difference between roughed up just
even a hair and smooth when it comes to epoxy on aluminum is night and
day.  This takes a bit more effort sure, you got to dissasemble the heads,
put rubber plugs in the guides for protection, and have a blaster, but the
results will be amazing for doing it.  BTW even a $10 Harbor Freight pail
blaster will do two heads sufficiently, and you could just use fine blasting
sand $5 for 50 lb.  And I'd wash the heads off after dissasembling them real
well first in hot water with degreaser.

After that, my next rec, conversion coat.  Alodine, you can do it at home.
Get it from a good machine supply place or if that isn't available, PPG car
paint places sell it for a ludicrous markup by the quart ($15) or so as their
aluminum conversion coat prior to painting.  But it is just alodine solution
marked up about 4 times.  Take a washpan, brush the blasted surface for
a good fifteen minutes or so with the solution (which you can save), wash
everything off a few times in steaming hot water with your favorite cleaner
(watch phospates on aluminum, you must use them sparingly).  Then do
the JB, I'd do 2 applications myself as it shrinks back in.  A neat hint here
if you got a MityVac BTW is to evacuate your JB after mixing.  Mix it up in
a milk jug lid, then put it in the MityVac resevoir, plug the end, and pump it
up, watch all the bubbles come out.  Let off the vacuum, pump it again, hold
it for a few minutes.  Really, really decreases the amount of voids when you
apply it.  Apply with a good condition putty knife or the edge of a single
sided razor.  Let it dry, the slow JB, OVERNIGHT.  Sand off at about 240
the next morning using a little aluminum block to keep the paper flat.  Then
you'll see that in the dips it has sunk away, so sand into them by hand again
(remember adhesives are all about cleanliness and "tooth") clean it up with
high grade alcohol, another JB, again overnight.  Sand a final time at 320.
Finally reassemble the heads, personally I'd hand lap the seats at least,
check the guides (probably OK on the higher end of spec at 120k or so),
and maybe if the exhaust were really ugly, I'd pop for the $10 each to have
them zipped clean (any shop, the 9mm guide is common Ford escort or
something, so anyone will have the guide and a 45 degree stone) and pop
a new valve in, but I doubt it.

Put em on.  Use a NON ACETIC ACID silicone like VW supplies in the set
or a good Locktite product.  Although that isn't going to save you, no reason
to tempt fate from the start.  Why do it all?  Well even doing all I've
mentioned,
even if you bought the Alodine, the $10 blaster, a $10 hood, $10 in sand, etc,
you are still under $50.  You got to fab or buy a bug style spring compressor
as the waterboxer dual springs are tough to get any other way (but that was
a bug rocker arm and 5 minutes with the welder for me) but even then another
$20 or so.  Do it all, do it right and you are $75 plus $100 in a gasket
set to
Bus Depot, and are going to get 75-100k out of the things.  The repair is a
solid weekends work engine in Van (put it up on ramps for better sitting room
before you start) and will save you $500 or more.  And I don't look on this
as a kludge or cheating fix.  BMW reccs JB-Weld (by name no less) to
repair a similar sort of problem on the first generation M3 engines, why
sweat it.  You've got to factor in as always how the heads are from a regular
old standpoint, guide wear, condition of the valves, that sort of thing, but
for anything under 100k those things aren't likely issues in a waterboxer
that has not been abused.

Having said this, a lot of people have got 75k more out of a set by just
picking at them and sloshing it on, so do what you will.

The fix as I've described it using a certain level of anality works well, and
I'd warrant is probably as good as having them ground out and welded.
Again as always, YMMV, I'm not at all afraid to jump into a van I've done
this to 50k ago and drive anywhere, I've seen the corrosion re-started on
rewelded heads with 20k service and on the new AMC heads with about
10k on them.  So pick the fix that gives you enough peace of mind.

John
jander14@wvu.edu