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Hi,
is it wise to coat the outside of the barrels with black hi-temp paintfor better heat dissipation?

Regards, Rob

You mean the ones surrounded by a water jacket?

No,
i mean the aircooled Type-1 barrels.

Your choice of forum just confused me. Unless of course you are building an oxy. I have painted some, and not painted some. Never saw much difference between the two.

Pretty sure colour does not greatly affect heat dissipation, certainly not at cylinder temps.
Probably worth it for rust protection.

AMBROSIA wrote:Pretty sure colour does not greatly affect heat dissipation, certainly not at cylinder temps.
Probably worth it for rust protection.

you'd be suppised but colour does make a big difference to heat.....

I've done no testing personally for cylinders but read a lot about it in books

When you're talking about heat absorption, as in from exposure to sunlight, color matters greatly. Also a factor in heat radiation when an object is so hot that it's visibly glowing..but for an ACVW cylinder that's living in the dark, not so much.


Black has better emissivity of energy in the infrared region of the spectrum, whereas other colors "specialize" more - but at the temperatures encountered on an engine cylinder, the surface texture and cleanliness is at least as important (a rough finish has more surface area). Another reason to select black IF you elect to paint, since the pigments in (flat) black paints typically cause a slight increase in surface area...but consider that a little oxidation of the surface accomplishes the same thing


When all is said & done, though, the difference between emissivity of painted vs unpainted surfaces is very slight in this application. Pretty much a cosmetic choice.

I always paint the cylinders.
Dupli-Color gloss black.
Cosmetic and to prevent rust obviously.
Never had it burn off any engine.