heat sink colour - makes a difference?
 

so, according to the laws of physics a black object will radiate heat better than a silver one. so if i was to spray my engine head black, would i notice a difference in engine temps? or would the effect not be noticeable?

Well, I think the first law of physics you would want to look at would have to be how well the paint conducts heat. If the dried paint is a crappy conductor ( which it is ) of heat, then black paint might be the least crappiest color you could spray paint your head.

I would venture to guess that the color of the head has no significant impact on the cooling heads ability to dissipate heat.

The paint color does not really matter. If you have 2 heat sinks one is polished and one is painted or anodized. The painted/anodized one will dissipate the heat faster/better than the polished one. Lightly painted not gooped or slopped on. What the paint/anodizing does is raise the emissivity of the heat sink(head) and thus is dissipates heat better.

Anodizing is better than painting.

Thermally speaking,
Chuck

Do a Google search. I did before and found a detailed study on the emissivity rate of various colors of anodized coatings. It does make a difference but not really enough to concern yourself with.

Here it is. scroll down: http://www.electro-optical.com/bb_ra...tlemisivty.htm