[matchframe]

I got into a discussion with some friends of mine about painting the underside of the intake. They were saying that if you paint the underside of the intake with heat resistant white paint, that will allow the intake to run cooler which will help in fuel flow. Also, they mentioned that if you paint the top half of the intake black, that will dissipate heat better allowing the intake to run cooler.

Anybody here do this and does it really make a difference?

 

[Eddie 70]

I don't know about painting the top of the intake black but I did see an episode of Horsepower last weekend and they were painting the bottom of the intake with ceramic spray paint. I was wondering about the durability of the paint. I am sure it is not going to stay put. It would seem to me that not painting it would be the better choice.

 

[TimAT]

Black supposedly dissipates heat better, but I'd sure be concerned about painting anything inside an engine with something that's not designed for an environment like the inside of an engine. Imagine a flake of paint getting between a cam and lifter. OR enough flakes getting to the oil pump screen. Guys have been painting the inside of blocks for years to get oil back to the pan faster, but the only thing I've ever heard of them using was GE's GLYPTAL. If you really want to keep the oil away from the bottom of the intake, why not fab a heat shield?? Full length of the valley and just open enough to allow oil to drain.

:cheers:

 

[OldVetteFan]

I ran one of these Moroso lifter valley trays in my small block a long time ago (I don't remember if it was made by Moroso back then).

P/N 25050 for SBC

P/N 25100 for BBC

http://www.moroso.com/catalog/categorydisplay.asp?catcode=13100

(most of the way down the page)

It isn't designed for roller lifters, though (wasn't a problem for me back then!).

The idea behind the black paint is that black will conduct heat better - but I've never actually seen any real world test results for that theory. However, I generally painted my blocks and heads black when I was rebuilding engines, so maybe I buy into it a bit (sounds good, and customers always seemed to buy into as well :huh: ).

That said, I never intentionally got paint on the inside of the block or heads, so I'm with Tim on the "I don't want paint flakes ruining my day".

Steven

 

[racervette69]

What about a air gap intake.

 

[RTGordon]

I don't think either would make a difference. Ceramic coating on the underside would provide a little insulation from internal heat (maybe worth it), but plain old paint would probably make little difference. Color would really only make a big difference if it was exposed to a bigger radiant heat source like sunlight.

 

[yellow73sb]

I ran one of these Moroso lifter valley trays in my small block a long time ago (I don't remember if it was made by Moroso back then).

P/N 25050 for SBC

P/N 25100 for BBC

http://www.moroso.com/catalog/categorydisplay.asp?catcode=13100

(most of the way down the page)

It isn't designed for roller lifters, though (wasn't a problem for me back then!).

The idea behind the black paint is that black will conduct heat better - but I've never actually seen any real world test results for that theory. However, I generally painted my blocks and heads black when I was rebuilding engines, so maybe I buy into it a bit (sounds good, and customers always seemed to buy into as well :huh: ).

That said, I never intentionally got paint on the inside of the block or heads, so I'm with Tim on the "I don't want paint flakes ruining my day".

Steven

Raw dissipates heat even better

 

[vfpreacher111]

Raw dissipates heat even better

YEP !!! Any coating you add will insulate against heat but WILL also "retain" the heat applied, even longer. Raw will retain and then dissipate the heat, the fastest. Even polish medal ,while giving better flow, will retain heat longer. There is not a coating made that will "withstand" the interior of a motor. If you absolutely have to re-coat the "exterior" of the intake, I suggest "aluminum powder coat".



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[OldVetteFan]

Raw dissipates heat even better

Yeah - but I just didn't like looking at an unpainted engine! Therefore, since I was going to paint it anyway, I'd just paint 'em black.

Steven

 

[saudivette]

...If you absolutely have to re-coat the "exterior" of the intake, I suggest "aluminum powder coat".

I will be powder coating mine this weekend. I'll post pics if anyone's interested...

 

[SMYDA]

This is a Edelbrock manifold that was bead blasted and Clear-Powder Coated.

(Will strip the valve covers next and paint them the same color as the block,
the exhaust manifolds will get painted black. This motor is going in the
daughters 4x4.)

 

[OldVetteFan]

Even polish medal ,while giving better flow, will retain heat longer.

What's the mechanism by which simply polishing a metal surface causes it to impede heat dissipation to the atmosphere?

Given the mass of an aluminum intake, the minor amount of irregular surface area removed by polishing wouldn't seem to have any significant effect on heat transfer.

Help me, Obe Won! I don't understand!

Steven

 

[chevyguy1969]

i might be off base here but what i have been told is that when you you polish the surface you reduce the surface area of the part thus reducing the cooling properties. someone please correct me if this is wrong.

 

[vfpreacher111]

Dude that built my motor, gave me this info.
What gives raw metal its rough texture, is the open pours in the metal. When you polish metal, you are "folding" these pours over on to themselves in a uniform manner. Essentially, closing the pours. That's what gives it the shine. Uniformity of the surface. In doing this, heat is unable to escape the metal as quickly as open pours. This is the reason you don't see professional drag racers with pretty, polished motors very often.



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[big2bird]

I would be willing to bet the difference is miniscule.

 

[saudivette]

Dude that built my motor, gave me this info.
What gives raw metal its rough texture, is the open pours in the metal. When you polish metal, you are "folding" these pours over on to themselves in a uniform manner. Essentially, closing the pours. That's what gives it the shine. Uniformity of the surface. In doing this, heat is unable to escape the metal as quickly as open pours. This is the reason you don't see professional drag racers with pretty, polished motors very often.

Huh? I've never heard of that before. What gives the metal it's rough texture is that components like inlet manifolds are sand cast. What gives the shine IS the uniformity of the surface but because you have removed all the "high spots" when polishing it. I've never heard of "folding over" the pores before.

I would have thought that the reason you don't see many professional drag racers with pretty engines is because they don't give a rat's arse about pretty, they want functionality.

I would be willing to bet the difference is miniscule.

The difference would be MICRO miniscule. If you ever look at an air cooled aero engine, look at some of the cooling fins. If they are damaged (through FOD etc) you can blend the damage out pretty savagely.

The way to improve heat dissipation would be to increase the surface area by a great deal - like putting cooling fins all over it, and painting it black.

 

[Guru 4 Hire]

Do it right.

www.swaintech.com

 

[vfpreacher111]

I figure I would stop the "he said she said". Since I did not know if I was regurgitating bull **** or not, I called Edelbrock for a straight answer. I got a "wiggly" answer.... after being on hold for 40 minutes

http://www.edelbrock.com/automotive_new/misc/tech_center/install/index.shtml

Quote:
"Polished aluminum will be hotter and retain heat longer "in theory". No science behind it other then "which is hotter, a chrome header or a black header...? the chrome header will be hotter for a longer period of time. That's easy to prove with a digital heat temp. gun. There will be no discernable difference in temperature between a polished or unfinished intake"

So... I'm sorry. Sounds like I was regurgitating bullshit.



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[AK's Z06]

Dude that built my motor, gave me this info.
What gives raw metal its rough texture, is the open pours in the metal. When you polish metal, you are "folding" these pours over on to themselves in a uniform manner. Essentially, closing the pours. That's what gives it the shine. Uniformity of the surface. In doing this, heat is unable to escape the metal as quickly as open pours. This is the reason you don't see professional drag racers with pretty, polished motors very often.

The rough surface comes from the sand cast process. Peening folds/closes a rough surface, polishing certainly won't remove casting defects unless you remove material mechanically.