Grill paint on DA Head?

[notorious_benny]

	Quote: Originally Posted by Flyinhigh
	I believe paint color to be an aesthetic feature - like chroming n Harley engine. Not all Lycoming performance built engines have black heads.

Yes but if it were such a problem they wouldnt paint any of them would they

[notorious_benny]

http://www.einsteinathome.org/ask/archive/misc-qa1.html

http://www.madsci.org/posts/archives...1057.Ph.r.html

Some reading for you,......

[plaster93]

Hummm ZDZ has painted there heads black?

[Flyinhigh]

I don't mean to sound like such a doubting Thomas, but the caomparison is apples to oranges. We aren't talking about external heat sources, but rather, heat generated from inside. The painted heads get hotter, because they contain the heat generated from internal combustion. (insulation) It isn't a huge difference - just about 15 to 20%. They read hotter, because the inside of the jugs are hotter - the painted fins do not actually make contact with the cooling air.


Use this analogy. Make a long solid mass of paint, and a separate long solid mass of aluminum ( an piant rod and an aluminum rod, if you will). hold a heat source at the end of each and take a temp reading at the other? Which do you presume will conduct the heat with the greates efficiency.

It isn't complicated physics to me. I learned about condems in the fourth grade

Benny, given your cridentials, you have my respect and attention. I'm just a carpenter who has grabed rubber-handled and metal handled tools in the Texas sun. I just have an intuition about metal and heat.

[notorious_benny]

Exactly!! We are talking about heat generated from INSIDE the engine. The colour of the motor has very very little bearing on how hot it gets as there isnt a radiant source of heat upon it.
If we want to get technical the darker colour if anything will cool quicker, but in the case of our engines not by much.

So the argument that dark colours make the engine hotter is untrue, that is my fisrt point.

The second point made is that the paint must somehow insulate the heat generated from inside the model from the outside air. Firstly this would lead to a DECREASE in IR temp readings as they are reading the surface temp on the motor(the heat from inside that is conducted outside, an insulator would restrict this heat)
Secondly even if the paint offered some amount of insulation from the outside air it would be negigible and would not be enough to hamper the cooling of the motor. We are talking less than a millimetre of paint here.
I understand the point that your trying the make that paint is less conductive than metal. However I would stop short of claiming a thin coat of it on our model engines has some magical insulating powers that makes the motor run hotter inside......... It simply dosnt have the properties to achive such a feat!

[dmichael]

	Quote: Originally Posted by jaguar bone
	Do you figure there could be ANY problem using (500o) black grill paint on the head of my 50cc? I want the silver inside of my vane louvers to disappear. The MTS tuned pipe is painted and is holding up like a champ! Please advise! Thanks!

Install a black painted screen over the opening.

[jaguar bone]

	Quote: Originally Posted by dmichael
	Install a black painted screen over the opening.

dmichael -your post suggestion of pure indifference to all the previous banter made me laugh!
I need all the air flow I can muster from the restricted opening as it currently is. What opening I have appears to be sufficient - so I hate to reduce it - even an iota.

I DO find this an interesting discussion though guys!

I personally find it hard to fathom that couple microns of paint would even approach the realm of "insulating value" at all. I think I bestl spend a couple nights at a Holiday Inn Express though and get back to this -post haste.

I also have conducted my own informal testing in the scorching Fl. heat t learn that a light tan car will reach the same blistering freaking hot interior as a dark charcoal car within the same hour. Not sure if that adds anything of use to this 'discussion' but if you like a black car- don't let the fear of heat in the parking lot sway you from making the choice!

Gee, Da-um I didn't think of monitoring the cooling off parameters.- Guess it was just too hot to put ma brew down and go outside again to read the temps!

[Bill_Higgins]

I don't personally see any real reason to paint it since the only time you'll ever really notice it will be on the ground. Does this mean that your going to paint the entire tuned pipe as well being as it doesn't match the black on the bottom of the fuse ???

Bill

[jaguar bone]

	Quote: Originally Posted by Bill_Higgins
	I don't personally see any real reason to paint it since the only time you'll ever really notice it will be on the ground. Does this mean that your going to paint the entire tuned pipe as well being as it doesn't match the black on the bottom of the fuse ??? Bill

Thanks Bill for stepping in! On the ground is when I want the silver to disappear. Is painting the head with heat resistant paint going to create a problem - ie not recommended?

The tuned pipe is painted black - my camera and lighting is not depicting an accurate matching black color. It actually looks really great.

[rede2fly]

yep,, oh yea, i agree with him. when i check the outside temp of my beer cooler it is hotter than the inside. this being because of the insulation holding the cool fresh icey cool air in, therefor the outside must be hotter than the inside because of this being the way it is. i didnt invent it, but i know for a fact its true. now then when i check the thermos that i hold the brandy and coffee in (dont tell them this at work) on the cold nights i can verify that it does indeed hold the heat in and the outside of said thermos is cooler than the inside, therfor that being said it must be true that the cosmic debri is very cosmic, and insulation does work as designed. so with that being said, i think we all have to agree that, to paint it black as the stones said, would indeed be painted black. and with that statemet being made i think we can all agree that is the way the world was ment to be and i forgot one thing fed-ex sucks

[futurase]

I painted the entire KS can on my AeroWorks with Duplicolor navy blue to match the bottom of my Extra 260. It has ZERO effect on it. If you want the head painted, do it. It will not effect anything. A lot of model engines companies paint the heads of their engines. All the older YS helicopter engines had black heads on them. they did not even have big heatsink heads like OS engines always have. They ran plenty cool too. I ask YS why they painted the heads and the answer was for cooling.

Norman Ross Jr.

[Bill_Higgins]

	Quote: Originally Posted by jaguar bone
	Thanks Bill for stepping in! On the ground is when I want the silver to disappear. Is painting the head with heat resistant paint going to create a problem - ie not recommended?

Marc,
I just don't personally think the risk is worth the reward , if you catch my drift ! I mean heck...what are you gonna do if the cowl on your next 50cc yak is a different color ??? Recommended .....we'll we actually haven't done any coating of our own, so I cant really answer yes or no.

Bill