Paint the exhaust manifold or heat rider body?

My 29-27 was restored several years ago, but it looks like nothing cosmetic was done to the heat riser body or to the exhaust manifold (intake manifold was painted engine green). The rust on the exhaust manifold and heat riser really detracts from the look of the engine. I have seen pics of 2 or 3 other engines and it looks like they all had unpainted exhaust manifold and heat riser - but there was no rust and it looks like they were left as just bare grey iron.

I can take the rust off, but then should I do anything else?

After cleaning the exhaust manifold and heat riser on my '26-26 standard coupe, I painted the exhaust manifold with VHT 1300 to 2000 degree silica ceramic paint. Color is metallic nickel silver in appearance and looks great. No more rusty manifold! Available at NAPA.

For the heat riser, since it runs cooler, I painted it the original olive green engine paint to match the intake manifold. Is available from Bob's Automobilia.

Bob

We used "cast blast." Comes in a spray can and looks just like bare metal.

I used VHT flat black from Autozone.

You can see my manifold in my gallery.

Mike in Colorado

whatever you use it needs to be rated to a very hot temperature, I used something that was supposed to be good for "most" exhausts and it just flaked off once it got warm

Does it matter if the car will be judged? In restoring misc. parts, I have always preferred painting them so that they will last with a good appearance that is close to original. Eastwood makes a number of metal tone paints for this purpose (cast blast, aluminum, cast aluminum, etc.). All are close, but of course if you look you can tell the part is painted. I have been wondering if that kind of finishing is inappropriate in an AACA judging context, or if everything that was originally unfinished must remain as such.

Also, hidden hunter is correct. IMHO, you must use the 2000 degree silica paint. In my experience, other "exhaust" paints will flake off near the ports and the manifold will rust.

Update, just noticed that the VHT 1300 to 2000 degree silica ceramic paint is beginning to flake off on some surfaces. The manifold was wire brushed, and cleaned with acetone prior to painting. I don't believe that the manifold has exceeded 2000 degrees. Now looking for an alternative.

Cast iron is porous so it may be something you have to continue to clean and touch up in certain spots. Once they get oily, they are extremely difficult to prep for paint. You can clean the surface, but if the part was oily, it will sweat out when it is heated. I have heard of people baking them off when off the car, but installed I don't know of any prep tips.

Lacquer thinner is about your best bet for cleaning.

I look at lacquer thinner as the universal solvent.

You may want to look into a couple of products here; "Cast-Blast" from Snyder's Antique Auto Parts in Ohio and "Calyx" from the Eastwood Co. out west. These two coatings seem to have long years of duration staying on the manifolds.