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High temp paint

4K views 4 replies 4 participants last post by  Kevin45 
#1 ·
Does anyone know if the color you paint your engine matters heat wise? I was going to paint my block black but everyone says NO! "That holds to much heat" Paint it silver or a light color. Is this true?
 
#2 ·
It's all about light. Black gets hot because it reflects no light of the color spectrum as where white reflects all color and stays cool.
A certain color in a dark area does not matter, it's all about the kind and chemistry of the paint.
If the color black will see light it will get hotter than other colors but if it stays in the dark all the time there is no reason for it to heat up anymore than orange or blue or white.
If you plan on running with your hood off at all, don't go black.

Think about a black shirt vrs. a white shirt outside, obviously the black gets hotter.
Now think about a black shirt and white shirt inside a house where it's a hundred degrees, they will feel the same.
 
#3 · (Edited)
Back in the late 60s or early 70s a top Pro Stock guy (Bill Jenkins, I think) started looking into the color of the engine. While it is true that the "Light" reflection factor is there, there is also a "Heat" reflection factor, since heat and light are both waves.

Here is the weird part of his results...
The paint is the same color on the inside as the outside of the surface painted. A black engine sees the inside of the paint and lets the heat out.
So his motors were painted flat black.
Basicaly the heat is not transfered as easy to a light color paint layer but is reflected back into the metal.

In a street car using a dark compartment would let more of the heat be absorbed by the sheet metal and the engine might run a little cooler. Of course remember, this is not a remedy for an inefficient cooling system. However this could be a big factor in an over heating car if there is little air flow through the compartment.
 
#4 ·
paint

Man ,I just painted it silver, Think it will get hotter now? So what your are telling me is that the black paint absorbs the heat from the block and then disperses it from the reverse side? So if I painted my block silver will the heat reflect back into my block? Where would I go to read about this study?
 
#5 ·
I really do not think at the temperature an engine runs at, that you will see much of a difference with different colors BUT.....

The paint is the same color on the inside as the outside of the surface painted. A black engine sees the inside of the paint and lets the heat out.
Have you ever noticed some heatsinks on electrical components / circuit boards? They are flat black. That way it draws the heat to the heatsink away from the component. So I suppose you could look at an engine the same way. But there are so many variables that I really don't think color makes a difference. If you would monitor under hood temperatures, headers will make the underhood temps hotter over stock exhaust manifolds. And headers will reduce engine temperatures, but with underhood temperatures increasing does any of that absorb back into the engine? A hood insulation lining will hold heat in versus no lining, and the rubber control arm dust shields will keep it a few degrees hotter versus air flow around the engine. Also consider the size of the thermostat that you are running and does the engine have a decent fan shroud or not. So the engine probably does not really see a difference between, orange, black, silver, or even white.
 
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