Can it be done? I sorta screwed one up today I've been watching Dirty2's build of the Caddy powered Deuce, and answered his call for a left-hand early exhaust manifold, since I've got an extra 331(junk) core under the shed.(I like helpin' my HAMB pals) The end bolts came right off, but the center bolts broke, and their remains were rusted tight into the manifold, so I broke out the pry bars and screwdriver.......and I might 'o got a little rough with it.......and put a small crack across the face of the center port bolt bosses It's just a crack......I didn't break off a big chunk...and it's not even all the way thru the manifold---matter of fact, IF it leaks, it'll be around the bolt itself. Soooo.......is there a magic elixor the bolt/hole can be slathered with? Can it or should it be brazed? Left alone? I KNOW it's hard to ***ess without a pic--sorry--it's in a box on the way to Danny's Dirty Compound. Anybody got any input?
Same here. As long as there is no pressure on it it should be fine. Preheating a bit will help. I know there is a magic temp. but I'm not sure what that is, Around 400 degrees comes to mind? I remember another Hamber said he heats them up in his BBQ grill. Your trying to raise the temp. a bit slower than just hitting the trigger on the torch. Then weld. let it cool for a minute or 2 then stress releive it by tapping the weld area with a ball peen hammer's "peen" end. Then slow down the cooling process by wrapping it up in something like a welding blanket to slow the cooling process. Or back in the grill and reduce the temp gradually and let it sit in there until it is cool. The faster it heats and cools the higher the chance of it cracking out again. This is info that I've aqquired over the years and have had success with. Maybe someone else can add to it or correct any points that may need to be corrected. Cast can also be ARC welded with a high-nickel rod. It can also be brazed to seal a small crack. ......................Mike.
You may want to give this stuff a try. I have never used it myself but it looks like it works pretty good in the videos. http://www.muggyweld.com/castiron.html Additionaly to grinding out the crack, drilling 1/8'' holes at the ends will help it from spreading should it crack again.
I drove a 350 for quite a while with a cracked manifold -- as soon as it warmed up the crack sealed itself. Cast iron can be welded -- I prefer to use a nickel alloy and arc, but that's just what I learned from my pappy As mentioned -- preheat and postheat. If you don't you're just making more problems.
about 10 years ago I had used a special rod for an arc welder for cast iron. Basic instructions - To repair a crack - drill small hole at end to stop spreading (probably not necessary in your case since it was self-inflicted). Grind along the crack to clean the metal, then make a shallow "V" notch out of the crack. Heat with a propane torch or acetelye torch, then weld with the rod. Let cool, grind smooth and it should be good to go.
isn't there a method where you drill out,tap and add bolts, something like that,I think its done for cracked blocks, but may work on exhaust manifolds too.s***ching i think its called
Another trick, using the torch, and brazing flux pluss coat hanger, heat the peice with the torch and when its about 250. preheat the rod and dip in the flux and weld in the crack just like brazing but better as your using high grade iron/low grade steel insted of br***. Let cooldow slowly and your done..Grind flush for the stock look...Roach.
guys if you can get by the old lady put the manifold in the oven for preheat on a cookie sheet and when your done welding put it back in, cools slowly that way or bury it in a pile of DRY sandblasting sand and forget about it for a few hours. take lots of patience to weld cast,very time consuming repair.
Peterson cast iron flux and cast iron rods , pre and post heat keep it from cracking again. sand blast clean 1st, you won't see the repair. tt
Heating it in the oven is the ticket. You shouldve seen my wife's reaction when she found one in the oven. It was cl***ic Funniest Videos winner material. Wish I had a video camera.
This is how I was taught to do it too. I never got around to doing it myself, only seen it done by a farmer I worked for when I was 15 years old. He used a BBQ also and the high nickel Rod.
I've actually brazed non-structural/non-load bearing cast with good success...seems like I'd try something like this for a crack to seal exhaust, but not for repairing a broken bolt hole...
I had a rams horn that was cracked repaired once- and got to watch the fella do the fixin. the prep was real basic- he cleaned it up first with a flapper wheel, then cut the crack about 1/8 inch deep- a little v' ing, but not much. he put it in an industrial over-bolted to a junk head. I want to say he got it to around 550. pulled it out, and welded it with a coat hanger...and his tig machine! and oddly enough, it came out looking better than most of the tig work I have seen. reeeally smooth. too smooth. I picked it up a couple hours later (it was still warm.) and took it to the shop where I took some 36 grit sand paper and a body hammer, and tapped the paper into the steel till it looked like cast. took some time, but it was pretty well seamless. but then again, if someone is inspecting your exhaust manifolds for cracks...they're too damn close to the car to begin with!
i use arctec #3 rods for cast iron, http://www.arctecalloys.com/index.htm High nickel electrode specially coated to provide a soft arc for all position joining and build-up of cast iron. Fully machineable. May be applied with minimal preheat. v the crack out first if its a car part that most likely has oil soaked into it then i preheat to burn that out and when i`m satisfied i start welding, i generly just use my cutting torch for heating and just go a little slow at first so the heat get a chance to transfer some, when i`d done welding i lay some ceramic blanket on it, you can get ceramic blank at any woodstove store. i have used these rods to weld marine manifolds the were cracked all to hell and no one else would touch with no preheating and they came out just fine.
What everyone else said, I heat them in the oven when the old ladys not home, grind a V, use a good stick rod, being the cheap ******* I am I use an old piece of insulation off the bottom of a car hood, wrap the part up in it real good, tie baling wire around it or something to keep it rolled up tight, toss it in the corner, let it cool for a couple of days. If you unwrap it the next day be careful, chances are you will burn your hand. Ask me how I know.
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