Black Paint DOES Run Cooler!

[viclioce]

There have been arguments presented by both sides of the thinking in the past, that black paint does or does not dissipate heat faster. I searched this on the web and here’s what I found.

Fact. It's been said that black is actually the best color for dissipating heat from the engine. This statement is true, here's why:

The reason black paint dissipates heat more than any other color is that black is the most capably dissipative color for infra-red (heat) wavelengths. As we all know, back is very absorbent when energy rays (visible AND invisible) such as sunlight hit it. It is also able to cast off the most heat energy, all of its radiation being in the infra-red part of the energy wavelength spectrum. Single colors tend to focus their ability to both absorb AND dissipate in the wavelength of their color, and far less in the infra-red compared to black. One last thing about black: It absorbs energy better than it dissipates it, which is likely why the effect of black dissipating heat is less known. Also, since it absorbs far better than it dissipates (as do all colors), it has a net gain, for example when your black car sits in the sun, until an equilibrium is reached depending on the heated body's ability to be cooled (like with a fender or hood, by the surrounding air). The ambient temperature of the air around the black fender keeps it from heating beyond a certain range. I hope this helps explain the "I don't know why" of black paint being a better cooler for engines. The effect won't be much, and might not even be noticeable unless closely monitored, but it is a fact.

Black radiates heat in the infra-red spectrum better than other colors, which tend to "specialize" by radiating less efficiently in the infra-red and more in just their color portion of the spectrum.

Speakers analogy: With regard to black being able to radiate heat well, heat is like a bass note, black is a woofer, and other colors are "mere" tweeters.

So I looked it up. Black does INDEED dissipate heat faster. Glad I could share this! Victor

[JPark]

I think my mind got dissipated somewhere along the way, but my librium is still equal.

[viclioce]

Well some would call it headache reading! But at least it does confirm that black paint helps a motor run cooler than an I painted motor! Victor

[Bullfrog]

. . . um, no discussion of the insulative properties of the paint coating?

. . . and what oil should I use?

Ed

[matt glascock]

Looks like its gettin' about time to whip out the Dremel. Captain? Keys please.

[Bullfrog]

Dremel tool relates to black paint how?? Still not sure whether the Dremel should be unlocked. (Mayhaps over on the stuck 03 piston thread? Seems like it may be time for careful conversion of a piston to aluminum flakes/chips.)

Ed

[matt glascock]

Then Hey! I'm your guy. Bring on the 03!!

PS - actually, the last time I repainted the jugs on my Sportster, I ran a fine grinding wheel along the edge of each fin for a groovie highlight effect.

[hodakamax]

I'm with Ed. Covering bare metal with a layer black paint is a different story and experiment. I'm also with Victor. Black paint probably disperses heat better than white paint. Science. Luvit. Maxie

[MTrat]

Black paint vs unpainted not measured here. No likely significant difference.

[JPark]

Maybe a rusty red would be just as good at infra red. No need to repaint at all.

And maybe oil goes black for a good reason.

[Bullfrog]

Maxie, I didn't take a side. I just pointed out that the discussion didn't review all factors.
Ed

[viclioce]

I just provided the information for the purposes of “Friendly Discussion!” I didn’t want it to become an argument.

I appreciate the point made by Capt. Ed regarding whether or not the coating of the paint holds in more heat or not. There was no info about that in the article.

I can only assume, and I hate to use that word but, that the author was discussing it from the standpoint of dealing with only iron or steel motors which are painted so they do not rust, rather than aluminum engines? And NO, we aren’t going to go into “Ford blue is better than Chevy orange!”

I also don’t know why Hodaka decided to paint the Model 99 & 98 motors black but not the Model 02 and other motors. Seems like they tried it and then abandoned it?

So let’s keep this discussion pleasant and not let it turn into a typical oil tirade!!! I already know the oil I use is best, because Danny Cooke said so!!! LMAO!!! Victor

[Bobv07662]

Black motorcycles are faster than any other color bike!

[Bullfrog]

Bobv,

I think you may be on to something there!

. . . and Vic, I see that you definitely "got" my intent when I drug oils into the discussion.

There is another topic which can be debated forever (even though I have the definitive, correct answer). "What is the best way to maintain your drive chain?" . . . and THEE answer is . . .



Yes!


(maintain your drive chain)
Ed

[matt glascock]

[viclioce]

. . . and Vic, I see that you definitely "got" my intent when I drug oils into the discussion.
Ed

Well, if Danny says then Danny says!!!

It’s more about having fun than being right!!! Victor

[thrownchain]

Way over thinking the whole idea. Go riding and clear your head.

[givergas]

lets see????

[Al Harpster]

Well, are there some known temperature ranges, in degrees F or C that are known to be damaging?

I'd guess if it's hot enough to seize that'd be one.

Iron cylinder, aluminum Piston..... Differences in thermal expansion resulting in excess friction.

Or, too hot & lubricant fails to lubricate & burns off instead.

All modern two stroke bikes are water cooled. They put out so much power for their size the heat has to go to water. Air can't take it away fast enough.

But what's the engine temperature danger zone?

Just wondering.

[Bobv07662]

I start to worry at 400'F.

[taber hodaka]

Jetting affects the heat more than paint. ------------------Clarence

[viclioce]

Old men effect jetting more than heat. ————————
Victor