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General Forums => The Mess Hall => Topic started by: mtgmike on February 09, 2009, 10:06:51 AM
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Anybody know what grade steel the factory manifold is? Mine is cracked, but i work at a heat treating shop. Guys here think they can weld it and make it hold, but need to know what the manifold is cast from first.
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Don't know but you might go over to Jeep forum and ask one of the Jeep engineers.
Just look for the latest community chat and see if you can pm one of the engineers...OR you may actually be able to post and get an answer in the same evening.
Good luck.
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It's cast iron. The key is to localize the heat and have a slow cool down so as not to harden the areas around the weld. Sometimes, if it's poorly welded, a crack may appear around the edges of the new weld.
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Preheating and proper annealing would be key.
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It is cast as stated above. The tricks, if you can call it that is to make sure the manifold is clean. Drill a small hole at the very end of the crack, this will help prevent the crack from growing when heat is applied to it. Bevel the crack forming a V the entire length. Preheat it, a propane torch will work, also it doesn't leave deposits. There are numerous rods for cast rods, a general repair rod should work best. Call a welding supply and they will help you pick the right one. I have used the 1/16" before, smaller rods work better for this type of work. They take less amps/heat and are easier to control. Lastly post-heat. This is where most fail and new stress cracks form. You can find more info on the net about pre and post heating. I would NOT try to weld it with a standard mig unit with standard wire. A TIG unit would work if you get the right fill rods. If you get the heat (amps) on your welder to high the casting will slag and deform. 50-60 with a small rod should be your starting point. See if you can find an old exhaust manifold to practice on first to get your settings.
Sorry for going a little long there,
Good luck with it,
JR