Finished doing the exhaust manifold gasket..removed a lot of heat shields, etc. Cleaned, primed and used VHT sparay paint, all went well EXCEPT..the exhaust manifold is stainless and the paint burned of. WHY ???..the rest of the parts are fine.
If you talking about stock exhaust manifolds on 2.8, Ive never found anything that stays on them for over a few weeks at most. I even tried some jet engine paint we used to use around the exhaust/ afterburners. Also didnt work. Maybe powder coating with heatproof coating would work, to much to bother with for me.
I have some paint that I had two cans off and it is nearly gone. It would stay on for long periods of time. But it is not made anymore and I find most of todays paint will stay on but it will grey out.
I suspect the ceramic coating and added heat just do not like the stainless.
I may try some Por 15 exhaust manifold paint when I run out of the other stuff. I really should experiment now on lower parts of the exhaust to see how it hold up.
Very odd. I would say the manifolds weren't clean of any grime. I have painted all kinds of exhaust, including many Fiero manifolds and y pipes. Never had an issue. My guess is contamination. Brian
The exhaust manifolds were perfectly clean, degreased, walnut blasted, and the only thing I did was use high temp VHT red paint, 2 light coats. The guy at the store said I didn't need a VHT primer. Every other piece of the exhaust, heat shield etc is fine, just the exhaust manifold look " gray", yet the brackets for the bolts to attach to the engine body are red... What gives/
Runnig lean? Timing? Part hotter then the paint will take? I believe VHT has some crazy heat cycles you are supposed to put it through to cure it.
I like Rustoleum "grill paint".
Also POR 20.
Generally most paints have things you need to do but no one reads the cans.
Even Ceramic coating need cycles and most people with new engines kill them breaking the engine in with the new headers on. You need to do heat cycles but when you break the engine in you can not do that. We recommend break in headers or old set of headers but few people do that.
I forgot to mention that I baked the manifolds after painting. Started at 300 degrees, increased by 50 degrees every half hour all the way up to the oven's max of 500 degrees. While the wife wasn't home, of course, because it did out gas quite a bit.
No peeling has occurred, just a little brownish discoloration where the manifolds bolt to the block.
I've also sold four sets of ported manifolds treated the same way and haven't had any complaints.
On the Vehicle •Paint must be completely dry before curing •Run at idle for 10 minutes •Cool for 20 minutes •Run at idle for 20 minutes •Cool for 20 minutes •Run under normal operating conditions for 30 minutes
Off the Vehicle •Paint must be completely dry before curing •Heat to 250°F (121°C) for 30 minutes •Cool for 30 minutes •Heat to 400°F (204°C) for 30 minutes •Cool for 30 minutes •Heat to 650°F (343°C ) for 30 minutes
I knew a guy that rebuilt Mopar engines locally. He painted them with regular spray can paint the oem color, then went all around it and heated it with an acetylene torch to 'cure' it. They seemed to last pretty well on cars I still see at shows all the time.
