I'm a true believer in using a ceramic coating - save up and do it! You won't regret it for a minute. This set now on my bird - was done by "Jet-hot" in aluminum finish, inside and out. They also offer a color that looks like fresh blasted cast iron. High temp resistant - and as advertised it lowered the underhood temp of the manifold by a couple of hundred degrees.



 
 Steve Metzger       Tucson, Arizona

Best way?  Sand blasting inside and out.  Removes rust, scale, carbon, slag and leaves a clean dry surface for paint.  Start out with high pressure, and lower the pressure for finishing to make the texture less rough.  I have ported several of them inside and left the inside with a polished surface.  Lots of work, but stealthy.  Joe-JDC

JDC

Bama, I have used caustic old oven leaner in the past to soften the burnt on carbon. Did that long ago. No sure if the new "reformulated" cleaners works as good as the old. Do wear gloves. - Bob 

AKA   Bob-93021

A youtube video of degreasing derusting a flathead engine using electrolysis. Check it out. Simple, safe( NO TOXIC RESIDUE) 

https://www.youtube.com/watch?v=njtyZzDBHzg
   Pete

In regard to cleaning exhaust manifolds, what is the best way to get the baked on carbon deposits out of the inside of the manifold?

I have had very good results removing rust from cast iron exhaust manifolds ( any ferrous metal ) by using electrolysis. Google it. Pete

I use a plastic barrel cut in 1/2 I have left some parts in it for over 1 year (forgot) with no problems, I have 2 bead blasters it takes to much time to remove heavy deposits, easier to just wash and put it in the barrel, also it cleans inside the water jackets.

You can use chemicals like Naval Jelly to remove rust.  It's messy.  I have them bead blasted then paint them with Eastwood's High Temp Coating.  It has the look of cast iron. A little goes a long way.  As you can see, I have had this can for years.  It's nice because you can touch them up later.

 

I like the VHT brand of high temperature paints. They sell a high temperature primer and then several top coat colors to choose from. In my personal opinion, I like to media blast rusty exhaust manifolds prior to painting. The media blasting provides a good texture to the iron for good paint adhesion. The fact that I have my own media blast cabinet helps!

  Ron Lane,  Meridian, ID

Cliff.  With the molasses mixture that you use, what do you use as a container for soaking large parts like cylinder heads and engine blocks?
In removing rust, the molasses mixture apparently etches the ferrous metal.  Do you use soaking vessels made of plastic?  Would galvanized steel be okay, or will the solution eat the zinc coating?

Thanks for the information!  


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York