Date:         Thu, 23 May 1996 21:52:40 -0800
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         tbf@pacifier.com (Todd Francis)
Subject:      Re: The transitional engine...no more corrosion?

>To: To: Multiple recipients of list <vanagon@lenti.med.umn.edu>
>From: tbf@pacifier.com (Todd Francis)
>Subject: Re: The transitional engine...no more corrosion?
>
> 
>> 
>>The best idea that I've come up with is Jet Hot Coating for the
>>combustion chamber, intake and exhaust ports and exhaust valves only.  It
>>would cost about 1-200$ per head, and I haven't called them to get the
>>details. Jet Hot is a metal-ceramic coating that can be applied to 
>>spcific areas and has been race and aircraft proven for years. It is a 
>>thermally insulating coating of extreme toughness. The coating bonds with 
>>the metal and requires a 3 step treatment. Another area that would be 
>>good to get done are the piston tops. The idea is to insulate the head 
>>and pistons from the heat of combustion, thus reducing thier temperatures 
>>and extending thier useful life.
>>
>>
>> I am currently putting a 2.1 engine together for my syncro that we plan
to take to Inuvik this summer. After removing the heads because of leaking
rubber seals , I found they were corroded bad enough that I wouldn't trust
them. I purchased 2 new heads and thought about how to prevent corrosion.
Ceramic coating came to mind and I went to a local shop (Portland,OR) to
find out about it. I had the surface done that the rubber seal goes against
and decided to leave the combustion chamber alone (about $60 pr). I had the
heads installed by a shop and drove for about 20,000 mi. On a trip to
sothern CA the little light came on in the dash. I checked the overflow tank
and of course it was full. Crap, blown head gasket. Towed home and took the
engine apart myself to see what was going on. I think the head bolts lost
torque or were not torqued correctly. Upon inspection of the coated heads
the coating looked great. There was already corrosion in the cylinder bores
where the green "O" rings slide into(yes I used  vw blue megabuck coolant).
This area was not coated. This coating is the same stuff that they put on
piston tops. I understand NASCAR racers have been using it for years. It is
meant to keep heat from transfering through. I figure that is a bonus
because it should keep some of the heat of the head from getting to the
spendy little rubber gasket that seals the coolant in. I think that the
cooler the gasket stays the longer it will last. These seals are the reason
I took the heads off in the first place. They were in tatters after 138,000
mi. I was impressed with how the ceramic looked and decided to have the
combustion chambers ,valves, and I had some different black ceramic put into
the exhaust ports. Having these areas done will keep heat from absorbing
into the head and the heat will go out in the exhaust. Of particular
importance ---- The coating shop has a ceramic putty that you can fill
corrosion pits in with, then you coat the whole surface and combustion
chambers completely($100 a pair you clean and take the valves out). I have a
friend that has 25,000 miles on his since we did that to them. No leaks so
far. I will soon be putting a set of badly pitted heads(repaired with
coating) on another engine and try them out. This definitly appears to be a
good deal but until we get a bus with 100,000 mi. or so then take it apart
to check the heads, who knows.
>  One other thing of interest. After 20,000 mi I checked the valves and
seats in the new heads I installed,removed, then recoated(you have to have a
valve grind done to remove ceramic). The valves were pretty warped and the
seats wern't in good shape either. I belive a new set of heads take a set
after a few thousand miles and the valve job goes away. I think this valve
job will stay much better since the heads are used. The heads are the
Spanish ones not German (I went to the Portland VW dealer to get German and
he only had Spanish.He claimed they were considered OEM. hmmmmmmmm.) I
suppose there has been a lot of discussion about the Spanish heads here but
being new on the list I havn't seen anything.How about them? Good? Bad?
>  If anyone would like to try this on they're heads please let me know. I
can put you in touch with the shop here or if you have another shop do it I
would like to keep track on how they work as the miles accumulate.
>Todd Francis
>86 Syncro Westy                Visulize no pitted heads
>