VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Exhaust Manifold Paint/Coating Burn Off

noticed on the 1930 the more i drive it the more the paint it coming off the exhaust manifold. i understand that the original paint burnt off.

i am just trying to validate/confirm that what i am seeing is normal. i know that the manifold was painted/coated when i got the truck originally from the previous owner who acquired it from the restoration shop. it was blasted, cleaned, and coated by a previous owner before he passed away.

below are a few pictures of the manifold as i received it. and then a few of it now. it started off small and just slowly progresses as seen, every time i drive it more and more crinkles up, then flakes up and off. i can run my hand over it and it snows black flakes.

Manifold Assembly as received

Manifold as of this morning

i can NOT confirm or validate what kind of coating/paint was used on the manifold.

generally looking at it now, the burn off seems normal in the way of heat pattern. since number 1 and number 6 are single and do not share a port, they still look pretty good, but then 2-3 & 4-5 are bare metal but they share ports, so twice the heat and exhaust going through them.

then at the collector, where all six come together to go into the exhaust pipe. then some heat creep up towards number six, since it is so close to the collector.

In general when i have been driving it, which i drive it approx every other weekend for 30-45 minutes around town, the temperature never gets passed a quarter. on a rare occasion when i hit every stop light and stop sign it may get close to the middle (straight up). i check it periodically when I drive, same with oil pressure, and charging. i even randomly pull my heat gun when i get home and shoot the cylinder walls ?175-185?, head ??, intake manifold ?175?, and exhaust manifold ?350-450? (need to look at notes to get temperatures) nothing looks extreme or out of range. it runs great, runs strong, no stumbling or hesitation ?!?

That is completely normal. Here is a picture from my dad's '31 motor. He rebuilt it about 11 years ago. It has roughly 15,000 miles on it. He used a regular enamel with a hardner. It looked really good for a while but eventually did exactly what you show.

You can see in my picture the paint is even stating to burn off the head.

He has seen that with some higher heat paint as well.

Within the last few months I remember that we had a thread going about painting exhaust manifolds.

The posts seemed to go in one of 2 directions. There were some who claimed that by carefully preparing the manifold, using special high temperature paints, and properly curing it, they could keep paint on the manifold.

Other like me simply let whatever paint got on it burn off to bare cast iron. That was what happened when they came from the factory. It might happen but I have never seen an exhaust manifold fail due to rust through.

Just want to add a variation to the discussion, I tried to 'cure' the exhaust manifold on my '28 Canopy Express.

I figured that it is cast iron, like a skillet. As per online instructions for curing a skillet, I coated the manifold with Canola oil, put it on an old cookie sheet, and baked it at 500 degrees on the BBQ.

It came out looking really nice. A shiny black.

But, it didn't take long to burn off and go back to surface rust.

It was a nice experiment. ;-)

Dean

There are a couple of coatings you can use if you desire. One is the exhaust manifold paint sold by almost every automotive parts store. Or you could use an old fashioned stove black.

I am perfectly fine with it burning off if all is well. never will know what they used on it, nothing in the paperwork i had or in the photos provided.

on the 29 when i did the exhaust manifold i cleaned it extensively and blasted it then used high temp Zinc Primer and Paint from KBS, then baked it per instructions. so will be interesting to see if and how it holds up over time, once i get it installed.

If using a stove paint I suggest using one that is made to look like original cast iron. I got mine at a wood stove shop. It has held up well for almost 20 years with a little burn off just at the inlet ports.

Thanks :)

I have been using KBS Coatings, they make an XTC that comes in 10 colors, including Cast Iron & Clear !! they always send me discount codes to order, right now they are doing 15% off KBS 15% Code

This is what i used on the 1929 manifold: KBS XTC High Temperature Paints-Primer they also make RustSeal which is comparable to POR-15. just sharing in case anyone is interested or want to try them. you can also order free color samples, on their engine coater the Chevy Grey is close to the BlueGrey from TFS.

I used Rustoleum propane/barbecue grill paint and mine still looks like new. I find it holds up better than the high temp paints advertised. I bet it’s simply relabeled black stove paint.