Paint it Black

[Shrek]

Would it help if you paint the engine black, and if so what else could you paint black? (Now i've got this song my head do do do do do...)

[Greyg]

I see a red door and I want it painted black.

[Jay2TheRescue]

The engine in my 86 chevy truck came black from the factory.

[TomO]

A black colored block helps to dissipate heat more evenly. But it also depends on what you're painting it with, as in what type of paint. They make paints that are available for radiators that don't inhibit the Heat transfer:
Eastwood Company

The short answer though is that the effect would be very minimal, probably not measurable against a control. But it sure would look nice.

[thisisntjared]

i hear water helps dissipate heat too... i think your on to something...

[zero_gravity]

i hear that if you use a black condom it looks invisible in the dark

[maximilian]

Uh, in total darkness aren't all colors invisible?

[theholycow]

It's better with the lights on, anyway.

[maximilian]

Depends what they look like, I suppose. I like to joke that I'm glad I'm nearsighted rather than farsighted because I can always tell who I'm in bed with. My being a massive geek adds some irony to this as I'm hardly fighting women off.

[zero_gravity]

if people call me a geek or a nerd these days i just say 'thanks. geeks make all the money'

[Shrek]

My thinking is that wenever you put on a black shirt on a hot day you'll start to get hot within the minute, but if you have a white shirt, it takes it a little while longer to get hot.

[NovaResource]

Actually, whenever you put on a black shirt on a SUNNY day you'll start to get hot within the minute. It's the sun making you hot. However, wearing a black shirt on a hot day while standing in the shade doesn't get you any hotter than any other color shirt.

So, unless you drive your black painted engine around with no hood so the sun can warm the engine, painting it black will have little effect on actual engine temps.

But, what do I know. Ask the experts here like BEEF and RIDE.

[aalb1]

Originally Posted by NovaResource

However, wearing a black shirt on a hot day while standing in the shade doesn't get you any hotter than any other color shirt.

I hate to call you out on a technicality but wearing a black shirt on a hot day while standing in the shade will get you slightly hotter. This is because black will absorb light and in the shade there is still light. Not as much as standing out of the shade of a tree but still there is light. Now if you were in a pitch black cave your statement would be true. Once again a slight technicality that probably makes me come across as a dick.

So now to the original poster ask yourself... is there enough light in your hood covered engine bay to merit painting it? I'm sure the differences are negligible.

Something else to discuss though is paint jobs on cars. Lately Flat Black or Satin Black paint jobs have been all the rage. Though aesthetically pleasing to the eye -- as they look real bad *** when you can actually keep dirt off of it -- flat black paint jobs absorb an incredible amount of light that a gloss coat would reflect. This light turns into heat and pretty much makes your car an oven compared to others. Make sure your AC it top notch!

Maybe a flat black hood would help you get what you're shooting for though.

[R.I.D.E.]

I was led to believe that black paint on an engine would radiate more heat to the atmosphere. An old friend who graduated from MIT with a degree in Theoretical Aerodynamics who raced Nissans in the 80s, so I guess he should know. One of the most brilliant people I have ever had the pleasure of meeting.

Now, for the purpose of mileage, you shoud try to retain any heat energy you can, so it would seem that there would be a logical argument for painting it with a white paint or even something with an insulating value.

I know one of the Insight hypermilers built a insulated cover for his engine. One of those hypermilers got 180 MG in a manual tranny Insight, averaging about 36 MPH.

Also the old Opel that got 300 + MPG a loooooong time ago had the engine covered with some kind of insulation, to keep it from cooling down when the motor was shut off.

regards
gary

[theholycow]

Too bad the black shirt doesn't radiate more heat to the atmosphere...white shirts stain when I'm outside doing yardwork.

[maximilian]

When it's hot I just dampen my T-shirt and let evaporative cooling keep me cool. When it dries out I just wet it again. I've done outdoor construction in greater than 90 degree weather with no problems (also drinking lots of water and using sunscreen). Of course some of you guys get hotter weather than that!

[theholycow]

Keeping fresh cool water on my clothes can help, but with me the water just gets hot really quickly and exacerbates the problem of sweat soaking my clothes and rubbing me the wrong way. Not much evaporation happens when humidity is 90%, maybe being further from the ocean you don't have that problem.

[maximilian]

Muggy days aren't real common here, it's true. I prefer water over sweat, if given the choice. My ex used to make wet T-shirt contest jokes when I did it.

[bobc455]

Sounds like some confusion here.

Gary is 100% correct. Yes, black does absorb heat very well. But, it is also the best heat-giver-offer. A quick google of "black body radiation" will probably give some insight.

Since the engine is essentially in the dark, there is no light to absorb as heat. However the black engine will radiate (give off heat) better, essentially making it cooler. That seems counter-productive since we've generally found results that indicate hotter is better.

However, the paint probably acts as a thermal insulator, offsetting the radiating effect (if that's what you are after).

-BC

[thisisntjared]

Originally Posted by bobc455

Gary is 100% correct. Yes, black does absorb heat very well. But, it is also the best heat-giver-offer. A quick google of "black body radiation" will probably give some insight.

i love technical jargon.

[trollbait]

I've picked up a few of those dri-weave athletic shirts on sale. They really work and are great for yard work. Moisture quickly evaporates off them, and they are thinner than cotton, so any breezes are more refreshing.

[theholycow]

I love those shirts. I have loads of them, WalMart marks them down all the time.

[itjstagame]

Yeah black absorbs light and gets hotter quicker but radiates much faster, white takes longer to cool down. So paint your block white and then insulate in white heat wrap :-). And then replace you bearings every 3k miles as you cook them.