lsengineguy

This may be a dumb question. Is there any advantage to coating the outside of a block - just like you would do to headers?

See reference photos of Swaintech coating below:

1989GTA

In most cases a header coating is a themal barrier. It keeps heat inside. I would think if you wanted to coat a block you would use a thermal dispersent to help get rid of the heat. Expensive process for no real gains that I know of.

lsengineguy

I thought that the heat is what makes the power. Isn't that why you want to keep the heat inside the headers?

XtremeDime

iTrader: (16)

For exhaust yes, you want the heat to stay inside the headers because the hotter the air the more its expanded and the quicker it moves. Inside an engine you want it to get rid of heat otherwise it will overheat.

chrs1313

iTrader: (24)

unless you are using a lead mixed paint on an aluminum block to pass the magnetic test for certain classes... ha

chuntington101

Isn't there a coating that can help remove heat from components??

Old SStroker

Not all tech inspectors have a lead magnet.

Did you mean a paint with iron in it?

If you are trying to dissipate head from a block, or other parts a thin coating of flat black is probably best. The coolant is going to reject the vast majority of the heat, so just paint the block to make it look pretty.


Jon

chrs1313

iTrader: (24)

you are correct meant iron

imma_stocker

iTrader: (19)

Black absorbs and retains heat so a white block would disperse the heat better

Surface area, so a crinkle type finish, dissipates heat faster than a smooth or polished surface.

DBL_TKE

I remember reading an article in Car Craft awhile ago regarding this. They tried different colors and recorded the results. I remember they came to the conclusion that chrome was the worst and black was the best. They tested other components in addition to the block as well.

chuntington101

I would have thought that the crinkle surface would have a greater surface area than a smooth finish would it not?....

Old SStroker

Where'd ya'll hear this?

t/a98

iTrader: (6)

i know right?? black absorbs light, rather than reflect it, i.e. white is the reflection of all colors, black is the absence.... i have heard black can disapate more heat, but not enough to make a difference, not even measurable... (dont know if that is true though, just something ive heard...)

Old SStroker

Perhaps you have thermal radiation and light absorption confused in your mind.

Don't believe everything you hear...or read, even from me.

Look it up.

Hint: good absorbers are also good emitters.

Yeah, it is measurable, but in the case of a liquid cooled engine, the coolant removes the vast majority of the heat, as mentioned earlier.

Lots of air cooled engines have the fins black anodized (if aluminum). This isn't just for asthetics.


Jon

imma_stocker

iTrader: (19)

That's what I thought I wrote

Physics 1, chemistry 1 & 2, Organic chemistry 1, and read it on the internet twice

FYI, a black shirt feels hot because it RELEASES energy faster than white. This is the inverse of black feeling colder in dark or cold, because it ABSORBS energy faster than white.

XtremeDime

iTrader: (16)

Did they cover the zeroth law of thermodynamics in any of those classes? If a something absorbs well it must emit well. Your original post said black would absorb and retain heat, it seems like youre saying it will dissipate heat faster now. Im confused.

imma_stocker

iTrader: (19)

Yeah we covered the 0th law, but apparently not proof-reading. No idea why I typed that

Old SStroker

I wish I'd said that.


Jon

t/a98

iTrader: (6)

hmm... threads like this make me with i retained more in my electrical engineering classes... dont mind me.. its my 21st bday so im prlly getting stuff confused...

joecar

http://en.wikipedia.org/wiki/Black_body

Painting it black makes it approximate a "black body radiator".