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FastWoman

Painting the intake manifold

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Hi all,

I have a leak in my exhaust and have to pull my manifolds ('78). This seems a good time for cosmetic improvements.

I considered polishing out the intake manifold, but that's a whole lot of work (as it is sand-cast), and polished aluminum really takes a beating here on the coast. Instead, I think it would look great with a painted finish, something like this:

http://atlanticz.ca/zclub/techtips/intake/normal_throttlelink2.jpg

I'd love to see other pictures about how this might be done. I have the less attractive '78 manifold with the webbing between the ports. I suppose the webbing is a practical thing, keeping more of the exhaust heat off of the injectors. I was thinking I could black out the webbing and paint the rest a color. This hammered blue isn't bad. Ideas?

Of course there's the practical matter of how to fair out the exhaust and which paint to use. There's not a whole lot of heat to deal with, except of course near the head, where the intake and exhaust ports are adjacent to each other. I was thinking of using thickened epoxy to fair out the rough aluminum. Would this hold up to the heat? And then after sanding the epoxy smooth, what paint would be best?

Thanks for your suggestions!

Peace,

Sarah

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Can't help you with any recommendations (definitely not my area of expertise) but I agree, that blue does look good.

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I was thinking of using thickened epoxy to fair out the rough aluminum. Would this hold up to the heat? And then after sanding the epoxy smooth

I think the epoxy should stand up fairly well to under hood temperatures and it should stick fine to the aluminum if you prep the surface correctly and don't put it on too thick. If it's too thick then the difference in the expansion of the aluminum compared to the epoxy will cause stress at the interface during temperature cycles. In other words if it's too thick it could delaminate but this is the case with any hard polymer coating on a heat cycled metal.

The epoxy will likely yellow so you will have to topcoat with something that is colorfast in a high temperature environment. You might try engine enamel but make sure that you sand the epoxy first to give the enamel a low gloss surface to stick to.

Good luck! I look forward to seeing photos.

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Go to your local Powder Coater and ask them about their hi-temp products. It will be available in a variety of colors. It's very durable and will stand up to the heat.

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I second pwd's opinion. Definately go with powder coating. That's the hottest part of the engine bay, right above the exhaust header.

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I'm not a fan of powder coating, so all I did to clean up my intake was to clean it by scrubbing with some degreaser then an etching wheel cleaner. It brightened up significantly and people noticed and liked it. I also enlarged the drain holes so they wouldn't get plugged so fast. It already has a heat shield, so I don't worry much about the heat from the exhaust.

Do you have plans for the exhaust manifold? Some local rodders will blast it clean, then have it plasma-coated with aluminum, and polish.

Edited by TomoHawk

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Eastwood makes a good coating for the manifold.As far as podercoating goes,the normal stuff melts at 400 degrees.

There is stuff called "Toon bright" that will clean up the intake good.

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I am not sure if Powder Coating would last since there is a bunch of heat where it bolts to the head. I am sure that there is a high heat coating available like a ceramic, but there may not be very good color choices.

Have you thought of Anodized Aluminum? Since the Intake is Aluminum that might make a cool alternative. It can be done with some cool colors and wont be affected by the heat.

Whatever you end up doing, now would be the time to mill out around the Ports and Throttle Body (if it's EFI) to increase air flow and weld up any unused fittings, etc.

FWIW: I coated my Exhaust Manifold with the Eastwood High-Temp Stainless and it looks really fantastic and has stayed that way for a long time.

Finally - Post Pics of before and after. We all need something to live vicariously through!!:beer:

Edited by ZCurves

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Whatever you end up doing, now would be the time to mill out around the Ports and Throttle Body (if it's EFI) to increase air flow...

Waste of time and money IMHO.

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Thanks for all your suggestions, guys! Wow, there are a lot of useful products out there!

I looked at some examples of high temp powder coatings, and they're gorgeous. The only catch is that they're done on glossy surfaces, and getting the manifold smooth is going to take either a whole lot of sanding and polishing or fairing out with an epoxy filler.

Mike, how long did it take for you to polish out your intake manifold prior to ceramic coating?

I also stumbled across Eastwood high temp ceramic engine paints:

http://www.jcwhitney.com/high-temperature-ceramic-engine-paints/p2023816.jcwx#

... which look great, but I would obviously need to start with bright, polished metal. I presume this is a similar formulation to the stainless finish, Andrew? Can I expect pretty good adhesion out of it?

I wonder how it would look on rough aluminum... Hmmmm....

It would be nice to clean up the valve cover and do it in the same finish.

Tomo, aluminizing the exhaust manifold sounds pretty cool, except that it's so buried you hardly see it. I was thinking of a high temp black exhaust paint instead.

Anodizing... Hmmm... Sounds interesting. Can that be done on rough metal?

Whatever I choose, it needs to be something that doesn't take excessive amounts of time. I don't want my car down for too long, as we live on low-lying ground in hurricane country. I don't want to have to evacuate the car by tow truck! ;)

Thanks again, guys! :)

Edited by FastWoman

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People notice my exhaust manifold all the time, even though t's so dark down under the intake. They suggest I get a new one, and have it aluminized or chromed. But if you do that, you might as well do the rest of the exhaust system too.

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But if you do that, you might as well do the rest of the exhaust system too.

I just did! ROFL I had holes in my exhaust and couldn't pass inspection. So now I have a new 2 1/2" MSA Premium aluminized exhaust with Magnaflow mid-pipe SS muffler. The problem is that my exhaust manifold gasket is leaking. Fortunately they didn't catch that on re-inspection.

I'll take another look, but I swear I don't see (or at least notice) the exhaust manifold!

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Normal epoxies don't go to high temperatures, but there are some that will. You just don't find those at the local hardware store.

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Thanks, Ztrain and Tomo. That would probably rule out the West System epoxy that I use for so many things. (Think boats! ;))

After a bit of searching, I found this stuff:

http://www.alvinproducts.com/Products/Products.asp?ID=2

... which is good to 1000F. Final curing is done in an oven at 450F. I think that's the stuff!

So I would apply this stuff, slightly thinned, to fare out the manifold's rough surface. I would be able to sand it smooth, probably before heat-curing (to make the job easier).

I'd then want to top-coat ideally with a deep blue metallic paint and/or powder coating. I'd be going with a deep blue because it would be compatible with the car's current silver color, as well as future plans for a candy-apple-red re-paint.

Any thoughts about high temp metallic paints?

I also have another thought: I've been entertaining the notion of inserting a piece of semi-rigid fiberglass duct material (for HVAC ducts) between the heat shield and the lower side of the intake manifold to reduce heat exposure. Not only would that benefit the longevity of the manifold's new finish, but it would also increase HP, decrease vapor locking, increase wiring life, etc. Any thoughts about this idea?

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How about some of the paints on this page:

http://www.tcpglobal.com/spraypaintdepot/metallic-effects.aspx

There's the anodized look in paints at the bottom -- VHT and Duplicolor. There's also some metal fleck paint at the top, but I don't know what the temperature specs are on it. Then at the very bottom of the page there's a metal fleck overcoat that's meant to be sprayed over a non-metallic base color coat. Hmmmm...

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I also have another thought: I've been entertaining the notion of inserting a piece of semi-rigid fiberglass duct material (for HVAC ducts) between the heat shield and the lower side of the intake manifold to reduce heat exposure. Not only would that benefit the longevity of the manifold's new finish, but it would also increase HP, decrease vapor locking, increase wiring life, etc. Any thoughts about this idea?
What are it's temperature handling capabilities? HVAC ducting doesn't reach the temperatures that are generated by an exhaust manifold.

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The factory makes a heat shield,but i'm not sure what models it came on.Having that thermal coated would be a decent alternative.

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Ztrain, my '78 has a sheet metal heat shield between the manifolds, but I don't yet know its shape.

Steve, The HVAC material might not be "designed" for that temp range, but I believe its composition is glass and aluminum. I don't think there's anything flammable or meltable.

Do either of you (or anyone else) know what temperatures we're dealing with underneath the intake? It sure would be nice to have real numbers, even if they're only approximate! ;)

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If you thermal coat the heat shield silver(or better yet-white)that will be your best "bang for the buck".Exhaust gas temperature is over 1300 degrees when it exits the head.

If you are still having a "heat soak" issue after that then something else is"out of sorts".

Edited by Z train

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Brake paint works wonders and stands up to many environments.

Here is my intake painted with silver brake paint from a spray can. This is about 7 years after I painted it and about 10,000 miles later.

404107679_d6pef-XL.jpg

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