Date: Thu, 23 May 2013 09:13:38 -0700
Reply-To: Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject: Re: quick and dirty head swap-dennis' 2 cents.
In-Reply-To: <BAY152-DS188CDF74710AA09E540663A0AA0@phx.gbl>
Content-Type: text/plain; charset="us-ascii"
Wow, more like two bits worth, or 25 cents, not 2 cents. That was painful
to read, so thanks for confirming my plan to convert to a Subaru! No leaks
so far, just low compression. I've sent in a sample for an oil analysis,
and I need about 3000 more miles of summer travel before I scrap it. If the
analysis doesn't show any antifreeze or excessive metal maybe I can make it.
I'd get a used WBX (with exhaust) if this one doesn't hold together rather
than tackle this job. I think it would re-define the term "can of worms" to
open this original engine after 28 years. The only things that have been
replaced are the water pump, starter, alternator, and AFM. I can put up
with the low power and leaky exhaust as long as it holds together.
Stuart
-----Original Message-----
Subject: Re: quick and dirty head swap-dennis' 2 cents.
I know this sounds a bit crazy but pulling the heads should not be taken
lightly and a quick and dirty job usually just means you need to have a good
towing plan. In the grand scheme of things the outer gasket only holds the
coolant in and small leaks don't mean a tow home. What is critical is the
seal between the heads and the cylinder sleeves. If you actually sand
blasted, not glass or aluminum oxide blasted you may have removed enough
material to prevent the heads from sealing there. Hylomar or Loctite 508
(with activator) can help this seal hold if used carefully. I also use the
Hylomar on the green o-rings on top and o-rings at the base of the
cylinders.
The sealant that now comes in the kit works very well. Years ago it sucked.
I have also used the "Right Stuff" there along with a bunch of other
products. Permatex also sells a rubber gasket dressing, 85409. Don't bother
with epoxies and other methods to seal pitted heads. This stuff will stop
all leaks out there forever. You don't want to have to remove it. You have
to be careful using it. The head has to be assembled before it begins to set
or it will over compress and destroy the new gasket.
The most important point to success is the torqueing of the nuts. They
should really be replaced. If not, you need to carefully clean the threads.
Get a high quality bottom tap (10 x 1.5). Run to the bottom of each one.
Make sure the threads on the studs are clean also. Any friction on the
threads will result in the studs twisting as you try to get to the final
torque. Do NOT put anything inside the cap nut. Use a nickel based anti
sieze on the threads of the studs. Fully cover the threads, no drips or
puddles. Use the yellow sealant from the kit only on the nut flange. Use a
beam or dial torque wrench for the final tightening. Apply the torque and
hold pressure until the nut stops turning. You will feel when it right.
There is too much twist for clicker type wrenches to be reliable. If you get
a nut that never seems to tighten beware, it will only stretch so far before
breaking. Even if you stop it may break later while driving. These studs are
shot. The original spec was 37 ft lbs. VW later changed the spec to 41.
If the cylinders are disturbed after you get it running do another oil
change. After 1,000 miles do an oil test to make sure antifreeze is not
getting into the oil. I have learned that I now pull the cylinders and
replace the o-rings at the base of the cylinders. Antifreeze outside of a
sealed system, heated, agitated and mixed with air becomes extremely
corrosive. Those pits in the head were not cause of the gasket leaking. The
gasket leaked and as the heated coolant reached the outside air it corroded
the head and caused the pitting. Note there was no pitting anywhere else but
under that gasket. Long before you see it in the oil it will start
destroying the bearings. While the cylinders are out I also use them with
some lapping compound the clean the heads where the cylinders have to seal.
You will see the high and low spots. With the cylinders in you want to use
a good straight edge to make sure the cylinders are level and parallel. If
not the case is twisted and again you won't get a good internal seal. One
more cause of combustion gasses in the cooling system.
As important if not more than the type of antifreeze you use is the quality
of the water. I buy pre mixed or use distilled water. I no longer use the VW
Blue stuff or dexcool. My favorite is the late model long life diesel
antifreezes such as "Final Charge" or the G05. Once on the final charge
figure yo never have to change coolant again. Regular hose and water pump
replacements will take care of that. The expected service life is 6 years or
600,000 miles in heavy duty engines with a one-time supplement at the half
life. It also has wetting agents (required for diesel Sleeve cylinder
engines) so no Water wetter stuff is needed. The only down side is that the
wetting agents also eliminate water's surface tension. So if there is any
chance of anything leaking it will and you get a crusty orange trail to find
it.
Dennis
