The Stovebolt Site Forums The Shop Area Engine Shop Should I use J-B Weld to repair Exhaust port?

Hi Gang, I finally got my manifolds ready to be re-installed when... upon cleaning up the Exhaust ports, I see they have been pitted by rust and they are not entirely flat on the bottom edge. Please take a look at the close-up pics using the links below to see the severity of the pitting.

https://docs.google.com/open?id=0B8Kq_P8shUUeVHdianpfZGtVbHc
https://docs.google.com/open?id=0B8Kq_P8shUUeZXljVG5naHdwMlE

My thought for a solution is to add a thin layer of J-B Weld to help fill the gaps, what say you??

I don't think JB Weld will hold up to the heat.

Thats the exhaust port, you would be better off using high heat silicone,(red). it will hold up with no problem, I have used it instead of gaskets on race engines using headers. It will work. I think the JB weld might not hold up that good, it will get too brittle from the heat.

Here is your answer from the JB Weld site

JB Weld FAQ

Basically it says JB Weld will hold up to 500 Degrees F. Continuous temp, 600 intermittent.Not recommended for exhaust manifolds, but I'm thinking the head itself won't get that hot.

They also have a high heat product they recommend for exhaust manifolds:

high-heat

That would probably work.

Kurt

Thanks All !!

When I read the title/question I thought to my self "no way, do the machine work to fix it properly..."
But looking at the pictures whatever you put in there will be trapped by the gasket so as long as it'll hold together and not turn to dust it might just work.

Grigg

There is a copper filled RTV that is for high heat uses. I have used it for ex. manifolds with good results.

There is a ceramic paste for high heat sealing to 1200 degrees F--used commonly by the people doing repair on steam systems(turbines, valves,joints, etc) that would work great here.The brand I am familiar with is called "copaltite".
If you have a friend in plant maintenance he might find a little.
I have often wondered about the "muffler sealants",that have been around since work began on Noah's ark, for this purpose.
Actually I think what I am seeing in your pics will seal with only a standard gasket-just retighten after a while and keep it tight.

Standard gasket and and copper RTV will do just fine. Let it dry a while before starting. I would bet if you take a flat sanding block and hit those ports a little, it won't look nearly as bad as you think it does.

Joe

The machine shop where I used to run the connecting rod reconditioning department had a BIG belt sander for cleaning up gasket surfaces like that. Just a quick pass over those pits on such a machine would be the best choice, but a very high-temp filler would be the next best thing. J-B Weld won't hold up to the heat present at that junction.
Jerry

Thanks everyone - I went with the Copper RTV

Does anyone know what the proper torque value for Manifolds should be? I just tightened them down real snug and they seem to be fine no leaks

Thanks very much I'm going to loosen things up and redo it tonight using the specs you provided