I am almost done putting my engine back together.I had it out so I decided to repaint my tins and fan housing. It looked like crap so I said what the heck. I kind of like the way the engine looks but the intakes for the carbs look horrible in my oppinion. They are cast and have an unfished look. Is there any reason why I would not want to paint them. I am thinking about flat black. In my oppinion it would be a cool conbtrast to the blue engine tin.Le t me know what you think!!!


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Anything but flat black!


You want the intake temp as cold as possible. Flat black absorbs heat better than pretty much any other color you can throw on there, thus heating up your intake.

The best would be something highly reflective. Like chrome.
Andy

ahhhh, Thats too bad because the flat black would look cool but apparently it would not be cool.HAHAHA.

Joe, you can paint them....

Use high temp paint, they get pretty hot.

considering I have not even put the lower end together...looks like you will beat me.


Rich

Rich would you advise against flat black? Sir andy thinks it could be an issue--I just think it would be cool. By the way Rich do you like old V.W bus. There is some guy down the street selling one. I think it`s kin of cool.

i once used the high temp spraypaint from flaps, looked great for 2 days.
Then i spilled spewed oil all over one side, and it took the paint right off. mabey needs to be brushed on???

It would not matter to me black, green, yellow...whatever.
BUT...I never thought about it to hard.
Its a 70 hp motor....put it in perspective.

Yes, I love old busses...where is it?
Worth a drive right now?
Is it a split windshield (two pieces) or a bent windshield (one piece)??

If its bright green, I know the car...out of my range.
Rich

found this on a quick google search, hope it helps.

"A black material has a high emissivity coefficient, while a silvery material has a low emissivity coefficient.

However, the emissivity coefficient cuts both ways, so to speak. A black material in thermodynamic equilibrium with its environment absorbs more radiation, true. But it also emits more radiation (this is necessary for equilibrium to hold). Likewise, a silvery material absorbs less radiation, and also emits less radiation."

That being said is looks like black is good for an oil cooler or radiator, but not so much for and intake.

Jim

Bead blasted aluminum powder coated clear looks pretty cool. On the other hand, you could polish 'em too.

If it's rattle can it will be gone if it ever gets gas or brake cleaner on it.

Porsche used a black coating of some kind on the intake manifolds of the 69 912, IIRC. Same for some years of 911 intake manifolds. The Cap'n

Thanks guys,
I think I will do 1 of 2 things. Either I will paint them flat black with high temp plate or I might even send them to one my vendors at work and have them anodized. That might look cool but I will need to do some research before I do that. Rich I drove down the street and the van was gone. It might be out in the guys back yard. I drive by everyday so I will P.M you after work tomorow and let you know how much,year,etc.

good point. i read somewhere in here to lightly spray your cylinders with flat black when building your motor. i did and don't regret it at all.

now black to your regularly schedualed program

mike

I would probably have them anodized. They have standard black. If your really woried about heat, it's the only way to go. Aluminum is an excellet conductor of heat, if you paint them you are creating a barrier between the alumunim and the cooling fluid (air). This barrier will retain a certian amount of heat. How much, maybe not alot, but maybe enough to create problems. Yo uwill not know until you try it. If you have an anodizer, the finish will not be removable without chemical stripping, but it can be scratched.
Just my .02

This is a context sensitive issue. Yes, without question, black absorbs more heat.

My question is, when intake air is rushing through there at the velocity it does, how much is it really going to get heated up in the time it takes to pass through those few inches? Just from the difference in temp created by the coating? I suppose it is possible under some extreme situations to measure a difference in performance, but you aren't going to notice it on this motor in a 914.

Cheap paint is just going to look worse in short order. Some powdercoats will hold up. Anodizing is interesting. Smooth and polish? I would just clean them up and leave them be. That looks pretty good. Goes with the carbs.

You would be surprised at how much air can soak up heat and then give it back up.

Take an air to air intercooler for instance...........

Make sense at all?

I'm more concerned about heat soak at idle or low rpm.

At high rpm, the venturies in the carb make the carbs and runners cold to the touch, but at idle there's just not enough velocity to keep things cool.
That's when you get heat soak.

Andy

anywhere you gain 1 or 2 ponys on an 80 h.p. motor...

Agreed! You really think painting runners that short is going to cost those numbers? I don't. In fact, I'd bet a jar of Travis' whipped lasagna on it.

At this point I`m going for cool looking not really increase in h.p.

Joe, their concern is that you might lose performance. You won't gain any, that's for sure.
(On the other hand, those '69 912 owners could pick up some horsepower by painting theirs silver. )

That, and the dreaded hot start problem ...
Andy

Looks good just like it is match`s the case half`s ....install it and run the piss outta it ...

Get 'em ceramic coated in the chrome finish. Best of both worlds!!!

-Josh2

O.K I think I will leave them for now.Thanks for all the input.

so....is it done?
Wanna drive to Wesport CT on sunday for a 914 BBQ?

Rich

Rich I would love to go but it is still not done. I am still waiting for the push rod seals to come in.Plus I will need a windshield because mine got cracked in the hail storm we had a few weeks back. My guess is that the parts will be here tomorrow and the engine should be back in by Saturday if we have no rain.