The bottom end of the new engine it togther and the heads etc are being finished. It was decided to bump the CR up a fair bit and because if this, ceramic coat the piston tops and combustion chambers and exhust ports on each head. I understand the theory behind this, eg to stop heat transfer etc.

But it was also suggested i ceramic coat the outside of the barrels, what are ppls opinions on this? i assume its a different coating to the inside as you want to be dissapating heat rather than keeping it in? is it a good idea?

Do not coat barrels with anything other than old fashioned black stove enamel. Any coating will impair heat flow.

judson that is incorrect,
research coatings and you will find heat dispersing coatings widely used in many apps ,for our need they are particularly good ,i have used it and and was very happy with the results however i cant give you empirical data as i didnt have another set to swap over too ,ceramic and heat dispersant coatings work well in my experience:beer:beer:beer

ANY smooth coating,weather it be ceramic or polished dog sh*t will REDUCE the ability of the cylinders to dissapate heat when used externally.The air flow will lose turbulance if the surface isn't "rough" and the cooling ability is reduced as the air flows over a reduced surface area.Do a search,this has been brought up before. Coating the inside of the head is a different ketle of fish...:beer

v8 supercars and almost every othre form of motorsport involved in extracting the last bit of performance will disagree with your sweeping statement,if you need to dissapate heat fast you need these coatings ,they are not ceramic and they dont smooth they ENHANCE the heat shedding properties of a cast piece be it alloy or iron,this stuff on plain ordinary cast iron cyls works and in conjunction with ceramic combustion chambers and ex ports and valve heads really gets things under control ,its not cheap, but it works:beer

Read this..

http://forums.aussieveedubbers.com/viewtopic.php?tid=5613#pid191792 

Ok well i have already done a search and read the other thread, but it turned into a thread with no real back up or data. just ppl slanging each other.

Done some more investigation, and the barrels will be coated with a heat dissapating coating, which is different to the ceramic coating of the piston tops and chambers.

the compression ratio really requires it (10.5:1). Its a 90% race motor... i won't talk about the cost. But hopefully will have it fully sorted for the hillclimb championships a mt cotton this year.......

Just a question when is the Mt Cotton hillclimb this year, thanks Damo.

which event? the first round of the tighe series is on the 11th of feb.............

OK Topless I guess my 30 years work in advanced engine research counts for nothing - so go ahead and coat your barrells and fry your engine. As others have said your signature is pretty spot on!

As a general statement I'll stand by what I said "any coating will impair heat flow" You can believe what you like about snake oil type sales information but the fact of the matter no engine manufacturer of air cooled engines use any form of coating other than paint or anodizing on aluminium barrels. This includes Porsche, Honda, Yamaha and also aircraft engine makers like Pratt and Whitney Lycoming. The risk of any coating that claims to improve heat dissipation is that if is not correctly applied a air gap forms between the cylinder and coating and this further impedes heat flow.

Rather than believing sales information educate yourself by searching the technical papers published by SAE and leading engine research universities like the University of Wisconsin. They have no axe to grind.

I'd save my money and stay away from coating barrels.

The links you posted are interesting as they all look like low budget operations and when you read about their heat dispersant coatings they sound like expensive forms of black stove enamel - which I originally said was the only thing you should coat barrels with.

The post topic is "ceramic coatings" and you are leading the even less informed to believe ceramic coatings of barrels are a good idea.

I'll stop my arguing now!



[ Edited on 26-1-2007 by Judsons4eva ]

The only real difference is in the cam selection, which is a little mild.

lol... here we go...

nick

craig craig...are you saying that if you win its simply the motor and not any driver skill whatsoever..if thats the case perhaps you should change from a pobjoy and see if u sitll win :p


Anthony

Bix, without getting caught in all the other crap, when I did my motor (2L type 4) in addition to ceramic coating the compustion chamber I also did the exhaust. The only other thing I did was to get a molybond type coating to the piston sleeves and valve spring.
:blah

Hi Craig, what sort of times do you run around mt cotton? i normally run road reg rather than imp prod.

There is also another bug (pobjoy powered) that just hit the road up here, and did its first run on the hillclimb a few weeks ago (more of a shake down).

Andy, exhaust ports are being done but not the ex system, i was going to heat rap that.

I have never raced at Mt Cotton, so the Australian titles will be the first time !!

Should be a good event, I hope you enter so we can both slaughter the escorts and datsuns

Do the exhaust system as well.