Anyone clean rust off of exhaust manifolds with acid. All the studs have been cut so they need to be replaced. My thought is this will help me get the studs out.
How long do I leave them soak and do I dilute the acid?

What kind of acid are you using? You don't want to damage other parts. I would just use BP-blaster or something like that to get the studs out.

The method I use for removing studs from old exhaust manifolds is to heat the manifold with an acetylene torch until the cast iron around the stud begins to glow red. I then use a stud extractor to unscrew the old stud. If the stud is broken off flush with the manifold and is too short to grab with the stud extractor you can drill it out using the heat riser block as a drill guide. After it is drilled out install a Heli-coil and install your new studs.
http://geocities.com/sdampier@sbcglobal.net/Team_Camaro/Stud_Extractor.jpg

The best method for cleaning exhaust manifolds is sandblasting. After I sandblast I paint them with the manifold coating sold by the Eastwood Company.

Has anyone tried the POR-15 manifold repair kit? It looks like it would be a pretty good kit for painting exhaust manifolds or headers. I am getting ready to sandblast a set of manifolds, so I am just curious.

I always just clean them to bare metal.
Ospo, and a wire brush
Then I use Hi temp clear engine paint.

They were not originally painted,
and that is close to the natural finish.
Lasts a good long time. use 2 coats.
Bake them in your gas grill between coats.

Used the oven once, many years ago - the wife still remembers that time. :(

akxtreme, I used por-15 exhaust paint on my 69 camaro 5+ years ago and they look the same as when I put it on. Absolutely no rust!

Pacecarjeff, that sound like a good story! :beers:
Sounds like the start or a new thread! But definitely good info!
68camaroZ28, thanks for the post on the POR-15.

Eastwood products also makes a high temp exhaust manifold coating. I just bought some for my firebird manifolds and will be putting it on this weekend. I have heard its good and from the pics ive seen looks pretty good as well. Will know more after the weekend.

I put Eastwoods on my manifolds. Followed the directions, and baked them in the oven...started to rust within a few months. Car was not driven, so maybe the oven was not enough to set the coating.

You can send them to Jerry Macneish he will aluminum skin them for around $200.00 they won't rust and should last for years. 410-781-0418