There has been plenty of discussions on this and many other boards regarding lack of heat transfer because of powder coating...They came from the factory with stove enamel on them not much different from powder of today I have several bikes powder coated with no ill effects...Some people say even polishing covers causes the engines to run hot but....Whatever you like should work I have some with engine paint looks just as good.. :rolleyes:
Strictly for the heat ransfer mechanism, no coating is best. And given that the A7/A10 barrel is cast iron and the finning is somewhat minimal, rust and thick coatings ought to be avoided. For moderate roadwork, however, Mike's comment is fine.
Re: powder coat cylinder barrels?#24857 05/16/072:46 am05/16/072:46 am
Even though I am a fan of powder coatings , I am in the "NO" camp on this one myself . The way I look at it , ading any coating is like throwing a blanket around the part , keeping heat in . This is good in an exhaust system , but bad on a cylinder barrel where you wanna remove heat . probably wont make a difference on an occasionally ridden bike ??
From what I understand, not all coatings are insulators. For example, Kal-Gard is supposed to transmit heat better than aluminum - and much better than cast iron. Plus, being darker, it also radiates heat more efficiently. Brit-Tech, for one, also markets coatings designed to improve heat transfer.
So has someone actually got a bike with powder coated cylinder?? Not sure if Mike Carter meant the cylinder was coated.. . I have a basket A65L, with Maroon powder coated EVERYthing! :rolleyes: , which at the time seemed like it could be interesting in a "retro" kind of way. Anyhow, I was also worried about the cylinder heat. KC
I did a radiative heat transfer analysis about a year ago with a .010" powdercoat thickness on a simple cylinder and found it raised the temperature by less than 1 degree F. Admittedly a simplification, but probably sufficient for an order of magnitude asessment. It satisfied me to the point where I have powdercoated the barrel on my SS90.
A smattering: '53 Gold Flash '67 Royal Star '71 Rickman Metisse '40 Silver Star '37 Rudge Special sixtyseventy Lightboltrocket road racer...and many more.
" radiant heat behaves in a very similar manner to light;it travels in straight lines, and is reflected by a polished surface and absorbed by a dull black one. the latter process is reversable, and therefore a polished surface emits less heat by radiation than a black on. the rate of emission from a polished surface is approximately one-tenth that from the same surface covered with a thin film of lamp-black, and the emissivity of a cast-aluminium surface is increased about 10 per cent by a THIN coating of black paint"
motorcycling engineering (1976) by phil irving, page 183, head design and materials