Date:         Thu, 17 Feb 2000 21:10:24 EST
Reply-To:     Wolfvan88@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Robert Lilley <Wolfvan88@AOL.COM>
Subject:      Re: Electrolysis and prevention of corrosion: It CAN be done...
Content-Type: text/plain; charset="US-ASCII"

All this talk about preventing the head gasket corrosion, makes me think
about WHY I had the sealing surface of my heads ceramic coated.

Keith in Calgary, Alberta Wrote:
<<<In summary, you can do a little to *slow down* the corrosion, but you
can't work around a design flaw. >>>

I think that something can be done...

To prevent the CORROSION damage, Bond to the surface of the item a substance
that DOES NOT corrode.  Aluminum coatings protect the aluminum beneath from
corroding. Airplanes have a great deal of aluminum in their construction.
There are a lot of products designed to protect the aluminum from corrosion
damage (Do a web search).

Others Vanagon owners have used different types of aluminum coatings to
protect the heads with great success.  I chosen to add a thermal barrier,
ceramic coating from Swain Tech.  Not only for the ability to protect the
aluminum sealing surface from corrosion damage, but also to REDUCED the heat
that rubber gasket normally faces.  This should prolong the life of the
gasket.  The coating of all parts that touch combustion heat were also coated
to control the heat, forcing most of the heat into the water and out the tail
pipe Not into the engine.

For instance: After running a highway speeds for @45 minutes, I can then
immediately remove my temp sensor II plug with no heat trouble (I needed to
check my timing after installing a new Idle control module), Before the
coatings it was very hot and difficult to remove.

Adding the sacrificial gizmos do nothing for the coolant that is forced into
the space between the head and the rubber gasket where the corrosion process
is found.


I have looked at there different engines head gaskets and each looks like the
corrosion was what was forced into the gasket surface forming pockets of
corrosion all to different degrees, embedded into the gasket, slowly
destroying the gasket.

Here goes my theory:
As the engine heats the gasket is squeezed between head and block as the
parts increase is size due to heat.  The coolant pressure also increases.
Then the engine is turned off, as parts cool they retract, But the coolant is
still under pressure and forces its way under the soft rubber gasket (time
factor is determined by the quality of the bond of the sealant to the
aluminum).  The engine is started and the gasket is again squeezed.  But the
coolant is trapped and small pockets develop in the gasket.  Soon the
corrosion process starts.  This is continued over and over, the pockets grow
in size and the corroded material grows in size and this then starts to cause
tiny tears in the rubber gasket small at first, then growing to the point of
failure. Some head gaskets are attacked from both sides and when the tears
meet there is catastrophic failure. The type of coolant and water quality
also factor in.



With the coatings the corrosion process cannot start and therefore the
pockets of corrosion do not develop that ultimately damaged the gasket.

While the coating do not guarantee that the head gasket will fail (ANY WATER
COOLED engine CAN suffer from a BLOWN head gasket) they should prevent the
corrosion from starting and increase the life of the gasket.



The question is why some and not others, Well I think it depends on several
factors.  The most important is "How the engine was put together." The
cleanness of the block and heads at assembly time and how well the builder
applied the sealant to the heads, the time of day/the day/the month all
factor into the engines success.  Then you have the care the Vanagon received
from its owner. Then the life that the engine had: hills/lead foot driver/FI
problems/Overheating/FI Vs Carbs.

Someone could give the car a pampered life, But still have failure because of
"How the engine was built at the factory"



Rather than abandon an excellent engine (The BEST of both the T1 and T4
engines) for something else, I have done what other owners have done, simply
fix the problem. But I also added some other improvements...

To coat the sealing surface the cost is was only $80 per head.
I got my New AMC heads from AVP and got a $100 credit for my old heads. Cost
of head was $325 per head.  The credit I received paid for the coating of the
head.





Robert