HELLO! hokey assed people! i know this isn't really old school.. yet I have just dropped a 1993 4.3L into my 65 olds. 4 bbl intake with a holley 2 bbl and point dist. plans are to make it a daily driver once again. my only problem... is that the exhaust manifolds dont quite clear the frame. i can make headers for it.. but thats too much work for this car. if i cut the "collector" off the manifold, can some exhaust tubing with a normal collector flange be welded to the cast iron sucessfully? im just a hobby welder with a 220 mig and a 275 tig, and have never welded to cast iron. which method would be best? thanks!
Not really lol... I always consider any cast iron welding to have a 90% failure rate... more just prepare for it to fail... But here is What I would do, got to the welding store and get some are welding rods for cast, not the brass ones, get the ones that have cast looking metal in the middle, just can't think of the name of those rods! Take them home and hammer the flux off them and clean em up... Put the manifold and the pipe in the oven and get it heated up, I usually go to 375, don't know why though lol! Then use the tig welder and the cleaned up arc rods to make your welds, when you are done put it back in the oven run it for 15 more minutes and then shut off the oven and leave the parts in it and let them cool in the oven slowly... Walla...
Cast iron to cast iron you can do it with a Nickel Rod., (pre heated, and allowed to cool naturally).cast to steel, not sure on that
That's what all the shops in town told me when I wanted to add some collectors to the ends of my exhaust cut-outs. That was until I took it to an old-timer. He brazed them up in about a 1/2 hour. Never had any problems with them. He smiled when I showed him the cut-outs and asked if I was going to "The Dump"? I didn't get it until he told me that he used to race back in his younger days and when someone wanted to race they'd race on the highway heading out to the dump.
Cast Iron needs to be really clean for Brazing, since Bronze doesn't want to stick to Carbon. Use a Carbine burr to get a clean surface, not a grinder, then preheat the casting. I'd rather find another donor manifold with the flange you want, cut and fit the pieces, and Arc weld with Nickle rods. Some people claim to have welded Cast Iron with a Mig, might be possible, but easy to do poorly.
Like I said I put every cast iron anything weld at a 90% failure rate... it will hold together for a while... but most stuff eventually breaks, just have to hope if it breaks that it is easy to get to and reweld That method has gotten me the BEST results out of any method...
You didn't say what the motor came out of.Maybe another body might have one that will bolt on.Try going to a local parts stoce that sells exhaust manifolds and look at them or there is always a salvage yard.... Steve
I put headers on an S10 blazer from Edelbrock. It was a 4.3L and they came either chrome or painted. They only cost me like 200 bucks.... whats your time and headache worth to you? might be easier to get the painted ones and cut and weld them to fit if they dont work instead of dickin around with the cast iron ones. to me trying to make that cast iron/steel tubing abortion work sounds like a recipe for a poorly built system. do it right, spend a few coins, and never look back or fight with it again.
Just because you people can't weld cast iron doesn't mean it can't be welded. The failure rate is directly related to your failure to learn how to weld cast iron properly. That being said, yes it can be done, but the effort put forth is not worth it. They make headers for 4.3 liters, you can find header flanges for them. You're gonna have far more work into trying to modify your cast iron manifolds than you would if you just built some headers. The cost of nickel rod and (assuming you even have a torch) acetylene and oxygen for pre-heat and post heat, you'd almost have a set of headers paid for.
please dont generalize like that..go back and see post #5 and realize i was the first to let him know it could be done if done properly
For what it's worth I have used those cast iron finials (that are used in wrought iron fences) and welded them to 1/2 hot rolled square bar with a 220 mig with .035 steel wire and 80/20 mix. Not subject to a lot of vibes, except when the wind blows.
It's not hard. As said, preheat to at least 350. use good nickle rod, then wrap in insulation, and bury the whole piece in hot sand, and let cool for a couple days. The preheat and slow cooldown are the critical parts, not the welding. This is a tri-power for a flathead Caddy that I did-no problems. Someone with better welding skills than I could do far better!
TIG with a stainless rod , it'll hold. I've done this several times. BUT preheat the cast and let it cool slow....
I figured the people that said cast iron can't be welded or saying it has a 90% chance of failing would know I was talking to them.
I've welded cast to cast on an exhaust manifold with a stick welder and ox/acetylene. Heat up the parts with the torch and keep the torch flame on the joint while running the stick (get cast rod electrodes from a weld suppy house). After the weld is complete, slowly remove the torch flame then put it in sand or wrap it in a weld blanket. I was also told it couldn't be done but it worked great.
You can weld cast iron depending on the material microstructure. Was just chatting with my school machinist about an odd looking part on the Bridgeport Mill. Seemed some one smacked a heavy cart into the one of the levels by accident (damn janitor moving steel cart around) . I asked him how he welded it assuming it was cast he said it was cast and he mig welded it back together.
clean part is a must A furnace if the part is big to pre heat the part torch cast iron sticks soda ash as flux heat the rod dip in soda ash heat and melt rod into crack heat to red hot but not where you see sparks where it just melts in after welding re heat the whole part than than slowely cool down was tought this way 25 years ago by a 80 yo man every part we welded never broke at the welded joint Paul Jug
Brazing works I've mig welded cast iron but not exhaust manifolds.Use Pre and Post heat with slow cooling 80/20 shielding gas Blue Demon- part no N155-G-035-10 ... dont recall if a 2lb spool is available,the wire seems to be of nickle content
fawk! i wish i was an old tymer.. but im not.... i am a broke sucka with more time than money.... cant spend any more money on this car, due to bills... sounds like im makin a set of headers this weekend.. then i can make shortys and not have the collector slam thanx for your input people....
Brazing will work fine for joining iron and steel, provided you follow the tips for joint cleanliness and sand immersion. It's been done for decades.
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