I am shopping for new exhaust manifolds. I found some at SNG Barratt. Does anyone have any experience with these? I am especially interested in how durable/long-lasting the porcelain coating is. Does the porcelain last a long time – or start to peel off quickly due to heat? Are there any other recommendations where to get replacement exhaust manifolds.
Thanks
Peter
Morning Peter,
Don’t expect any of them to last, my understanding is that the modern porcelain coatings do not have what ever the ‘magic’ ingredient was in the early coatings (lead?). If your careful and keep the water off them, run your engine rich so as to keep the heat down you may get a 1000 miles off them before they fail. On the other hand you might consider one of the ceramic coatings but to the best of my knowledge they still don’t have a gloss black finish.
Cheers,
LLynn
If you polish the cast iron, before Jet Hot’ing, you can achieve a pretty decent luster, that wont fail.
The porcelain on my manifolds was almost all flaked off so I sandblasted them and sprayed on a few coats of Tremclad 2000 black paint.
It goes on jet black but dries to a lighter black/gray colour. I am very happy with it as it has lasted.
Dennis
69 OTS
Loved mine but have the dremel ready
You have to massage the holes
Once done they are great!
Gtjoey1314
Huh, I guess that’s the step I omitted. Mine were blasted and jet hot coated and they look like a nice BBQ. How polished is polished, just smoothed or shiny like the golden toilet? Not sure how one accomplishes that. Will the coating adhere to shiny metal? I’ve had a spare set up in the attic for years waiting for some attention.
Are yours damaged/cracked? If not I’d be inclined to just have them reporcelainzed if you don’t want to go with ceramics. I did some research on various other forms a while back and came up with this list of vendors, Pacific Porcelain, Independence Porcelain, Prairie Porcelain, Parky’s Porcelain
Jet Hot is a bit like chrome: chrome isn’t really shiny, it’s a color.
Shiny chrome parts, like bumpers, are polished that shiny BEFORE plating: ergo…SHIIIIINY!
I have seen videos of folks doing the same to the cast iron manifolds—a metric f**k-ton of work—and, reportedly, yes, it adheres.
That’s 20% more than an SAE f**k-ton of work 
Ahhhhh: I see yer a scientist, too…
My new manifolds only lasted a few hundred miles before they started flaking. I do not believe any of the suppliers offer anything more durable than the others, so assume none of the new ones will last.
Crap! If that’s the case, then I should have ordered the un-coated manifolds and did what Dennis did with Trenclad.
Anthony
Thanks to everyone for giving me feedback on new exhaust manifolds.
