Stud was broken off in the head. Over weeks I tried penetrating oil and heat. I had no luck with a clean removal. Had drilled it out to where threads were starting to show, then carefully used the Dremel to go out even farther. Got to the point I wanted to run a tap down the hole and before I even got the tap started Ping! This. I seriously took this project slow trying to avoid this kind of damage. Rather frustrating. Since its on the end I'm really tempted to use a hardened bolt with a thick washer trimmed to fit neatly and just kind of clamp that end rather than try to fix the ear. Kind of the reverse of how some exhaust manifolds bolt up.
grind a bevel on both sides ...weld it up. I brazed one back together 25 years ago and it still holding with no issues
The bit that broke off came off in two chunks, so it'd be a total of three seams. Can you braze cast iron with the little oxy/mapp rigs they sell?
brazing a joint happens at much lower temps than welding does... you arent fusing the base metals as you do in welding, just bonding them. so, yes. in my opinion you can get it hot enough to successfully braze the three back together
I've brazed steel before for non-car projects, just never tried cast iron before. I've googled and read all sorts of stuff that have done more to scare me than make me think its doable, lol. I guess at least if I try and fail at the worst it's an exhaust leak, not exactly a life or death repair.
Hit a piece with the grinding wheel. If it sparks big red sparks, put a bolt in the slot and weld it with a mig. no preheating is required. Exhaust industry does it all the time.
I agree I have done this many times on sbc blocks were the mounting ear for the starter seems to brake often. Just use a lot of anti-splatter gel on the bolt. Or better yet get a piece of brass dowel to stick in the hole. Sent via Western Union Express
my dad has welded a lot of cast iron. he would preheat it the casting in the gas grill and then arc weld it with nickle welding rod. you should remove valve seals and de-grease the cylinder head first. having a machine shop burn out the stud with a edm machine may have been the better route. sometimes removing broken or seized fasteners can lead to more unexpected damage. the heating and cooling of the casting may have lead to the fracturing of the casting.
Or make an L shaped bracket that rests where the missing bit did to keep the bolt straight and apply pressure on the other side.
Are you suggesting to weld a bolt to the head? Or is the bolt just to keep everything in line while welding the chips back on?
I once disassembled and old engine that had a broken off piece like that and someone had just brazed up the whole end of it and redrilled the hole for the bolt. It seemed to have worked for a long time, but I scrapped the manifold because I went to headers.
you can braze the broken bits back on or take it to a shop and have them make a new section by piling up the braze and then drill and retap , this is how we do big engines as its kind of hard to put a 15 ton motor in a oven . its only holding a manifold on its not holding the crank in , but being a ford it might be ...
I fixed a broken off eat on a BBC exhaust manifold by building up some braze and filing surface flat and drilled hole for bolt,still holding 30 years later.
HRP I think on his engine he will have to replace the head. Just a guess on my part. As for brazing you are not going to get it hot enough with a little Oxy/MAP rig. You will have to get the cast iron red hot to make the braze work on it. Most cast iron that I have brazed I ended up using a rose bud to get it hot enough. if you have a stick welder at your disposal just get a few sticks of ni-rod and weld it. V it out and remember weld it a little bit at a time and peen the hell out of it.
Fooling around last night I ground one side off the head of a bolt, to clear the little reinforcement web there, and that feels like it would have a good chance of holding. I've also run across something called ThermoSteel that a lot of people have had luck with using on exhaust manifold cracks and such. I'm seriously tempted to try a carefully fitted bolt combined with a glob of this stuff.
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