Item Subject: Advice Rebuilding an 84  : head coating
     
Hi Todd,

  How much did it cost to have the water cooled used heads repaired and coated? 
How long have the used heads been in use so far?  I live in the Corvallis area, 
who and where is the shop in Portland you used?  Did you also rebuild/check any 
of the other aspects of the used WC heads before coating?
  I was going to look into some other coatings that are used in my profession 
(Machine Design), but I like the thermal insulating properties of ceramics as 
well.  However, that is an entirely different thread.  Any answers you can give 
to the above questions would be appreciated.

Thanks,

Vince.

______________________________ Reply Separator _________________________________
Subject: Advice Rebuilding an 84  : head coating
Author:  Non-HP-vanagon (vanagon@lenti.med.umn.edu) at HP-Corvallis,shargw1
Date:    12/18/96 1:03 PM

ROGunter@aol.com wrote:
> 
> Thanks Todd,
> 
>      What do you mean by "coating" a head?  Are you talking about coating the 
> surface that will touch the block with something that prevents contact
> between the metal surfaces of the head and the block?  What do they coat the 
> head with?
> 
> 
     
Hi Russell:
I'm sorry you got only half of the message I origanally wrote. I have 
been trying for about two days to get this message out. It goes to the 
list and half turns up missing. Can't figure it out. I have written 
other messages before and after and they have been working. Oh well, to 
the question at hand: I have been working with a shop here in 
Portland,OR. that applies Ceramic coating to engine parts. When I 
rebuilt my engine I bought new heads and had him ceramic coat the 
combustion chambers in order to keep unwanted heat out of the head ( you 
see, this ceramic coating is a high performance thermal barrier sort of 
like is used on the bottom of the space shuttle. In a engine application 
it is intended to keep the heat in the exhaust and blow it out the pipe 
instead of absorbing it into the head. In race car applications it is 
supposed to increase power.) and they also coated the whole surface 
surface surrounding the combustion chambers that touches the coolant. I 
figured that ceramic should not corrode so it should be perfect for 
controling the pitting of the heads. Also since this stuff is a thermal 
barrier it should keep some of the heat of the head from getting to the 
large rubber head gaskets which I assume whould add to the life of the 
gasket, and with the history of these gaskets any help is welcome. I 
also had the exhaust ports coated to keep heat from the head and I had 
the valve heads coated. They say the valves keep cooler when they are 
done. I have about 40,000 miles since rebuild with no problems. I won't 
really be able to tell how well things are going until I take it apart 
again, so it will be (hopefully) a while till I can really complete my 
report. 
I had a couple of other wc engines done also. These heads were used and 
badly pitted from corrosion. In this case the shop first filled the pits 
with ceramic putty then covered everything with ceramic coating , then 
they are baked at 300 degrees to cure the coating just like the new 
heads I had done. The seal surface came out very smooth. So far we 
havn't had any trouble with those heads either.
 I also had a couple of air cooled race engines (type 4) done. This was
done strictly to keep as much heat out of the head as possible. I have 
not done tests to find out if it helps, I just have relied on things I 
have heard and magazine articles that have talked about the stuff and 
swear it is the hot ticket (cool ticket?).
     
Todd Francis
91 Tristar
86 Westy Syncro