[Terry M. Hunt]

Everybody knows about the frustrating issue of paint burning off of the exhaust crossover on the intake and the exhaust ports on the cylinder heads on our Pontiac engines. Every couple of years I post something to see if anybody has come up with a solution, so here we go again. I know you can block off the crossover on the intake via various means. I did that with special intake gaskets(Felpro I think) on my 65 GTO, but I’m not aware of a fix for the heads.
Flipping through my Eastwood catalog I see 13795ZA High Temp Internal Exhaust Coating, which is described as withstanding up to 1800 degrees. It’s for headers, manifolds, mufflers. I wonder if applying this to the inside of the exhaust port would keep the outside surface cool enough to prevent the paint from burning off.
A similar approach would involve applying one of the available ceramic coatings used on the outside(inside also I think) of headers and exhaust manifolds..
Has anybody tried this? With what results? How far up into the port did you apply the coating? Could this approach backfire by increasing the exhaust temp passing into the manifold, head pipe, etc. to the point that you would have some failure there? Paint now burns off bottom of floor pan? Sound insulation/ carpet start to cook? Inquiring minds want to know.

[Geoff]

Every paint/coating known to mankind will discolour, if not burn off, on the centre exh ports.

[rwfisher]

A restorer in the East indicated to me to just accept the inevitable and work with it. He leaves those areas unpainted with engine color and instead sprays with cast color high temp coating keeping it thin. As it starts to turn from heat you can recoat with a brush application of same coating. It will still look like the paint has burned off but you won’t have the discoloration / rust you would normally. Touching up every season should help delay the ugly….

[Stuart]

I've also wondered about whether you could get one of the high temperature coatings like Jet-Hot sprayed inside the exhaust ports.

If this stuff from Eastwood is a DIY product, it seems like it wouldn't hurt to try - the worst that could happen is it would simply burn off.

I've had limited success with giving the exterior of the heads a light coat of high temp silver over those center ports, then applying the Pontiac blue. It seems to prolong the life of the blue paint, and when it does start to burn off it doesn't look as bad.

[burd]

OEM stays on, but it nay be out of buss. Duplicor is crap. Most others burn off. 23 years, it’s still all. There.

[geeteeohguy]

Burnt off paint in these areas is a sign of a driving, running car that is being used and enjoyed. The paint on mine has been burnt off for years and it's not even a thought. I drive my cars.

[Lee]

I used to apply Eastwood's exhaust manifold coating to the exterior of the heads, along the exhaust runners. That delayed the paint burning off, discoloring, then rust starting.

A few years ago, I was applying "cold galvanize" zinc-rich spray primer to a part. I had that part resting on the firebox of my smoker. Awhile later, I fired up the pit and cooked for about 15 hours. Although BBQ paint and other high temp paints always burned off the firebox, I noticed that the zinc paint had held up quite well.

Since then, I've used the cold galvanize as a primer on several engines (it seems to adhere better than regular primer) then apply the engine paint. I have around 1,200 miles on my own 455, since I last painted it. The exhaust runners have turned white, but no rust has appeared.

[G.T.O.boy]

The best paint that I have used is a single stage acrylic enamel such as PPG etc. mixed by a paint shop, it hold up much better than a rattle can. It will still discolor but not even near as bad as the rattle can paint. Used this on a show car and several daily drivers. Much better color and metallic's for the 66 and up and much harder paint that doesn't flake off.

[Terry M. Hunt]

I think I’m familiar with every brand of engine paint, every product that has been used as a primer/pre coat,etc,etc. since I’ve been dealing with this for the last 35 years. I have touched up engine paint many, many times by brush, air brush, etc. I’m just wondering now if there is some process involving the inner passages that will lower the surface temp enough that the paint won’t burn off. I’ll be rebuilding the engine for my 66 GTO this winter and hoped to come up with an answer without having to be the guinea pig for this myself.

[gtobob67]

I used VHT on the areas that discolor from heat and lightly mist on the blue. Here's mine with over 4000 miles on it.

[GT182]

I bought a spray can of black paint that resists heat up to 2,000 degrees. Tho I haven't tried it yet. I'll have to search for it in the garage to get the name of who makes it. But if you're in Home Depot, ask someone at the paint counter if they can find it.