Date:         Mon, 25 Mar 1996 16:31:56 CST6CDT
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "Dan Houg" <fairwind@northernnet.com>
Subject:      H2O Head pitting repair

to All:

Having just repaired the heads on my '87, i thought i'd post my 
observations and methods.  First off, i was agast at how corroded the 
sealing surface actually was.  I had pits 1/4" deep in the aluminum 
surface.  the neoprene gasket was baked and split in many places.  it 
is amazing that it held coolant at all.  read Tim Smith's treatise on 
crevice corrosion.  it applies to the heads in a most infuriating 
manner.

as for actually removing the heads, again Tim posted a nice summary.  
i won't go into detail on my experiences.  well, maybe a couple tips 
later on.  anyway, the head repair....

1-  Remove Head.  you be on your own for this.  it ain't for the 
faint of heart but it is do-able for a person with a reasonable 
arsenal of tools and a workspace.

2-  Examine Head.  cry a little.  think of the $560 you'll be saving 
by trying an marginally tested repair method.

3-  Scrape the bulk of the crud off.  after scraping, you'll be left 
with a deceptively smooth surface.  don't believe it.

4-  Pit cleaning.  i used an el-cheapo siphon sand blaster with 
walnut shell media.  this worked wonderfully to clean the pits out.  
also removed carbon nice from the ports.  spend time (and media) 
really blasting the gunk out.  then i switched to sand media and just 
evenly blasted the perimeter of the head to roughen the surface for 
the epoxy.  dig into the pits with a dental pick and root everything 
out.  take your time.

5-  mix up a small batch of JB Weld.  start filling in the pits.  
work the JB Weld into the pits with a toothpick so that the entire 
pit surface is wetted with epoxy.  do each pit and really work it in. 
 now start smearing the surface with epoxy, wetting the entire 
surface.  don't be concerned about getting a level surface yet.

6-  take a new, clean putty knife, maybe 3-4" wide and skim off the 
surface of the head of excess epoxy.  the epoxy in the pits will 
'pull out' leaving a slight depression and that is okay at this 
point.  let this harden overnight.  the working time on JB Weld is 
really nice so you don't have to panic and rush to get it smoothed 
off before it sets up.

7-  Finish Layer.  mix up another batch.  i like to use the bottom of 
an aluminum pop can.  fill the depression in the pits and apply a 
very thin layer over the scraped surface.  now lay a large sheet of 
wax paper over the entire head sealing surface.  let the epoxy start 
to set up a little bit so it isn't so runny.   take the bottom of a 
black plastic Kodak film can and rub the surface of the wax paper to 
smooth out your finish layer.  go from the center out.  do not remove 
the wax paper.  let this harden over night again.  then remove the 
wax paper.  it WILL come off after the epoxy is set but it will pull 
the epoxy if you try to remove it before it hardens.

8-  Examine the surface.  i was amazed at how nicely it came out.  a 
really smooth sealing surface.  let the entire repair cure at least 
24 hours before placing back on the engine.  i used a brooder light 
to warm the head for curing after the first 12 hours were up.

The Big Question of this repair is how long JB Weld will stand up to 
the test of time.  Based on the hardness of the finished surface, i 
expect good results.  Ideally, you could have a shop rebuild the 
pitted surface.  this is for people on a family budget.

-dan