exhaust manifold repair

admin

I have an exhaust manifold on a combine, that is cracked in two on one of the ports, I had to do some work on the machine and currently the manifold is off the machine,I have not ever heard of much success in welding of a exhaust manifold, and I do not want to make it worst..but was doing some reading on a tractor forum and it said there is some High temp epoxy that one can use, replacement is not a current option as I can not find a replacement, new or used.any ideas?I just want to hopefully eliminate the leak into the engine compartment,  It is not for show.~~~~~~~~~~~~edit, I suppose one could make a header type manifold for the old combine engine.why were talking manifolds  this is a gasoline engine,  on most tractors and farm type equipment the exhaust and the intake are joined, (my guess is to keep the intake from Icing up in the cold weather,  if one built a header type manifold would one have to add the extension on and  bolt that back to the in take manifold, I know we had one old gas tractor that in the cold it would ice up to the point where the throttle would not work, never bothered in the summer,~~~~~~~~~~~~~~~~~~I ordered a manifold for it as the salvage yard said they had one for the engine and they sent a diesel manifold instead of the gas unit, and there is no way the diesel will work on the gas engine. Had a head problem and found a low cost used head, and that they got right,Last edited by Farmerboy; 07-10-2012 at 10:18 PM.
Reply:If it's cast, I'd TIG weld it with 309L stainless filler or Ni55/Ni99.Welding/Fab Pics: www.UtahWeld.com
Reply:I had a post on this, search my old threads.What I did was had my dad heat it up with an oxy/fuel torch until it was cherry red and then mig welded over it. It shouldn't crack if you control the cool down from what I have read. Lots of people said to put it in a grill or something and drop it 100* every hour.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:O/A weld with plenty of preheat, very slow cooling off packed in insulation, and cast iron filler - old cast iron piston rings works in a pinch. There is cast iron welding flux available, if it doesn't flow together well without.Did a little practice welding cast iron, with pictures here: http://weldingweb.com/showpost.php?p...1&postcount=22Last edited by G-son; 07-11-2012 at 03:04 AM.
Reply:Someone mentioned 99% nickel rod..     That to me anyway, is probally a pretty good way.     However, it doesn't penetrate well, so a big V out is needed, and it does cost a lil money.    I usually use just 7018.   Only because I'm more in tune w/ the way it welds.    I V it out noticably more than I would regular steel, because cast iron fights off the penetration more than steel.    Then like everyone else said, heat the entire thing, then make the area your going to weld red w/ the torch.     I use a 3/32 7018, do small beads.     I literally have the torch going in my other hand while welding, I immediatly get the heat back on along the weld, and start peening it.   I probally peen it for half a min. w/ small brass hammer.    I do I light grind over the weld to clean it up for the next bead, the whole time keeping the torch near and around the welded area.   This cuts down on the cracking noise I would normally hear about 10 seconds after I run a bead.     When I get all done, I post heat a few mins, then bury the whole part in cat litter that I keep in 5 gal buckets.   It slows the cooling process.    Obviously youll tack this part together before welding making sure surface being mated to the exhast port is flush, and plan on losing some of that squareness due to warpage. I know someonewho has a big belt sander, they hold the whole mantifold up to it for a second, and kinda do a light half descent resurfaing.   I'm not saying this is better than tigging it, or what other people say, it's just what I'm most familiar w/ and it usually lasts a while.   However, sometimes the whole mantifold is in such deteriated shape, and my results dont last, or it cracks somewhere else.
Reply:In my experience there's not much you can do if it's going to crack. Usually it cracks immediately after the puddle has solidified. Peening, slow cooling, and all that is obviously just a waste of time if the weld has been cracking right behind the puddle. Preheating with a torch may help some. Situatioins like this are kind of the reason its common to use nickel filler due to it's solidification rate which matches cast iron better, or something...Welding/Fab Pics: www.UtahWeld.com
Reply:Hey Farmerboy,You may find the method I use to help you that is fairly easy & has superb results.Dennyhttp://weldingweb.com/vbb/showthread.php?t=73741Complete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:I took the cast manifold to town to some one with (what I thought was more experence than I had) and the simple was it was runined by the time I got back, so this was my fix,I think i am ready to put the manifold on the machine, if I counted correctly there are 29 separate parts that needed cut, machined, test fitted, welded, ground, etc,
Reply:Nice !Lincoln SA200's... at least 15 - 20. They come and go. Growing partial to the "Short Hoods" in my old age. Last count on Short Hoods was 13 in possession.
Reply:Surface grinder rates can be fairly inexpensive if you can find someone that specializes in it.  I recently had two exhaust manifolds surface ground and I don't remember the price but I think it was less than $500 (these manifolds were each 6 feet long and weighed 300+lbs a piece).