Can a cast iron exhaust manifold be welded? It is not a crack but a completely broke in 2 one. I have a post on the wanted board for a manifold but these seem to be rare. If anyone has parts or knows of some for a 1956 Dodge Coronet Lancer 270 cu. in. let me know please. Thanks.
I've seen them brazed in a flange repair, someone here will chime in. Here's a page w/some tips, cooling down sounds critical, and pre-heating. http://www.smokstak.com/forum/showthread.php?t=11744
I've seen them brazed, too, but never two separate pieces butted together. That's certainly not to say it can't be done...I've just never personally seen anyone do it. Back in the days when brazing cast was more common form of repair I think a replacement manifold might have been the way to go, of course that's not really feasible now... You're going to have to find someone who really knows his shit for this one. Might be best to bolt it to a head (or jig) so its in correct alignment and not able to move around from the heat. Ay chance you can replace the exhaust with headers???
I've used a stick-welder rod made by a company called "Muggyweld" to repair two cast iron machine tools with good results. It's not cheap (as I recall, something like $60 for half a pound of rod, including shipping) but it works. It welds cast almost as easily and smoothly as 6011 on steel. I've found that the first pass tends to have a little porosity, but grind it out and the second pass butters on better than a MIG weld. Very little or no preheat is needed, and postheat is as simple as throwing a piece of insulation over the part to let it cool fairly slow- but how slow isn't critical. Doc.
buddy of mine just did one, built a fire in his charcoal grill, put the manifold in it untill it was real hot, brazed it in the fire, then let it cool real slow. Split manifold on a straight 6. worked good
Last night at NAPA Auto Parts I saw some low nickle "cast iron" rod. Must be pretty common if it is on the shelf at a parts store. Try doing the repair on a mid 70's 350 manifold first until you get comfortable enough to weld your rare manifold.
I tried welding an exhaust manifold on a Nissan a few years back without much luck. Maybe it was the quality of the cast iron?
Might consider sending it to the Chapin Machine/Welding Shop in Chapin, IL. If they are still in business, they will furnace weld it right for you! OR, a good diesel head welding repair shop in your local area. pdq67
"Welding cast is easy" if you have the right stuff. Find a shop that has a spray metal torch. The one I have is a Eutectic brand and uses their metal powders. I spray a high nickel powder for automotive manifolds and it works good. I've fixed a few dozen and none have come back for a second fix. You'll want to get the two halves good and clean by shot blasting and/or grinding. Be carefull not to thin anything more than necessary, but you do need to bevel the joint as with other welding methods. It works best bolting the manifold (pieces) to a matching head and heat the entire assembly to ~400 degrees. You have to "weld" with the metal powder while the parts are hot, and then cool them over the course of several hours, so a bake oven is required. I use the one we pulled out of our kitchen the last remodel. If you've got a good welding supply house near by they can probably tell you who in the area has the equipment, or could sell you the setup for a few hundred bucks. Ovens are cheap at the crusher! Good luck!
I've had good results welding cast with ER70s6 solid core wire. ER70s6 is more commonly known as "hard wire". It's pretty much the standard MIG wire. If you have a MIG setup, chances are that's what you're using. I think it works well due to the high silicon content. Just make some nice bevels and give it a try. I've welded numerous cast iron things with this wire, from tractor seats to exhaust manifolds, even a head or two. Never really had a problem. The worst that could happen is that you'll have to prep it for welding again.
I welded my SBF manifold. Grind surfaces to a deep V. Heat with a torch until HOT. Weld with nickel rod. Wrap and let them cool. Hammer the weld to relieve stresses. I bolted mine to an old set of heads.
Chuck; The brass will hold the pieces together for awhile, but exhaust is corrosive, & will rot the brass fairly quickly. &, welding to fix it after that would be very difficult, as you can't weld over brass, & get a worthwhile weld. Marcus...
Brazing is the least satisfactory method, even though it's the easiest. The different coefficients of thermal expansion between cast iron and brass combined with the environment (repeated heating and cooling in a constrained mode) will doom the joint. Various specialty arc weld rods used as intended (pre and post heat) improve the chances for survival. The best is to gas weld it with cast iron rod with plenty of pre and post heat.
Hit it with a grinder if it sparks you can weld it. I weld a lot of ot manifolds. Grind clean, use your mig. If you can do it bolted to the head, weld it there let it cool it will be ok. 95% of the time
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