Summershandy

Broken Manifold

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My heart sank today. While trying to remove the broken flange bolts the actual flange broke. I tried every trick in the book. Heat, easy out (which did it), candle wax and tapping with 50/50 acetone and ATF. What a bunch of bull***. I work gingerly but never thought in a million years this would have happened. It's too late now but I should have gone with my gut and just drilled out the threads and use a nut and bolt. I will NEVER try unseizing frozen bolts again! Any suggestions what route I could go? Maybe there's a creative machinist or engineer out there.  

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What kind of car is it? Is it an irreplaceable thing or could another manifold be found that should be in decent condition? I've been through this (believe me!) and I know the frustration. Fortunately, that area might be able to be welded, drilled, and re-tapped to be useful if you can't find a replacement manifold. I wouldn't try welding the little pieces back on, but a competent cast iron welder should be able to apply enough molten metal to that area to create a reasonable facsimile that could be finished to look and act like the original mounting ear.

 

Unfortunately, nobody ever designed these old cars to last this long and the materials used are often well beyond their expiration date, especially something like a cast iron manifold that has been subjected to hundreds of thousands of heat/cool cycles, which is tough. It stinks, but it's not unusual.

 

I'd start looking for a good replacement manifold as a start. Good luck!

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If I couldn't find a good one and had to save that one I'd grind off the broken ear and clean up half way around  the exhaust port. Then I would make a semi circular piece with the ear to fit. I would drill, tap, and screw the new piece to the manifold. Probably use  three or four 10-32  screws on each side of the ear. Then I would  also braze the  new piece to the manifold. 

It's a demanding project but if done with care should work.................Bob

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Welding cast iron isn't that hard.  Find an old-time welder who specializes in fixing farm equipment.  We have one such person in town and he repaired the same sort of broken ear on my friend's Ford exhaust manifold.  He's also welded a cast-iron drill press base for me and it's been fine for nearly 20 years now. All it takes is using the correct rods. 

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10 minutes ago, Summershandy said:

 

My concern is the amount of pressure the bolt will exert when the exhaust flanges are snugged up. Thanks for all your suggestions! 

 

 

That's why I suggested the 10-32 screws in addition to the braze. IMO the way that's broken in pieces it is not a candidate for welding. Of course you could try welding, if that fails than try what I suggested. If that fails you are no worse off.....................Bob

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Surely there must be someone up there who can gas weld to fill in the broken area with gray iron rod, grind, drill and tap it.

There HAS to be some resourceful folks up where you are....... ;)

 

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Being cast iron, it will all have to be heated while welded then cooled slowly so it doesn't crack. I suppose it could be built up with rod (arc or gas) or even by spray welding, which is much more costly.

Edited by Spinneyhill (see edit history)

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MOST manifolds need to be gas welded unless the iron is in excellent condition in which case Nickel 99 MIGHT stick.

Gray iron filler rod will always stick, won't get hard and will blend in with the parent material.

I welded my share of manifolds and heads.

Don't over think it.

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57 minutes ago, cahartley said:

Surely there must be someone up there who can gas weld to fill in the broken area with gray iron rod, grind, drill and tap it.

There HAS to be some resourceful folks up where you are....... ;)

 

Ya I'm gonna check it out and put them to the test. I thank you all with all your thoughts and opinions, you guys rock! I was super bummed today but your posts give me inspiration. I can sleep better tonight. Cheers!

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Here is one of the options discussed.

Image result for corvair exhaust manifold fix

 

Or this which is like a saddle around the neck and put in new longer bolts. 

 

Some form or fashion of this repair has been around for Corvairs since the mid 60's.

 

Image result for corvair exhaust manifold fix

 

But I believe that it can be welded with a good welder.

Edited by Larry Schramm (see edit history)

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50 minutes ago, Larry Schramm said:

Here is one of the options discussed.

 

Pretty much. But since his is in 3 pieces I would fabricate the piece and make it big enough to accommodate 2 or 3 screws per side and then also braze it in place.  At least that's what I would do but I have a pretty complete shop..............Bob

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2 hours ago, Larry Schramm said:

But I believe that it can be welded with a good welder.

Or just a welder who doesn't know better! I have MIG welded stainless steel studs to many a cast iron Corvair manifold with a broken ear just like your picture. Just like the Bumble Bee that cannot fly, it works for me!:D

 

Speaking of the original issue, on Corvair manifolds I never try to remove the rusty remnants of the steel studs, I just cut the remainder stud flush with the ear, center punch as close to the center of the stud as possible, drill with a 5/16" bit and tap 3/8-16. Yes, once in a while the broken stud actually breaks free and turns, but usually around here they are so rusted it is like a solid ear.

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13 hours ago, Summershandy said:

My concern is the amount of pressure the bolt will exert when the exhaust flanges are snugged up. Thanks for all your suggestions! 

And a properly welded repair will be just as strong as original. Don't make this harder than it is.

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My suggestion is to repair the original. Muggy Weld offer two grades of arc welding rod for cast iron, one for burnt cast iron (#72) to adhere to the "high carbon" metal and the other (#77) is applied over the #72 weld which can be machined.

https://www.muggyweld.com/knowledge-center/#cast-iron 

They have a number of tutorial videos. I have personally used this and can recommend it with confidence.  Pay attention to the type of arc welding, they want you to use a back stitch motion, which is the way the arc welding rod is held and deposited. You don't have to heat-warm the entire manifold, though I do suggest warming the repair area with oxy-accel (rose bud tip). Then machine as needed.

An article of this topic: http://www.secondchancegarage.com/public4/welding-cast-iron-1.cfm

PM me for more information.

Edited by Friartuck (see edit history)

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6 hours ago, Frank DuVal said:

Or just a welder who doesn't know better! I have MIG welded stainless steel studs to many a cast iron Corvair manifold with a broken ear

 

This is so far the best fix idea. Clamp the stud in place  and weld it up solid...................Bob

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2 hours ago, Bhigdog said:

 

This is so far the best fix idea. Clamp the stud in place  and weld it up solid...................Bob

Originally they were bolts, but turning it or both into studs all welded up does sound good. 

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Brass nuts can not rust in place. OK, technically they can corrode in place, but that bond is easily broken the next time it needs to be removed.

 

Stainless nuts sound like a problem solver, however, stainless nuts on stainless studs (or bolts) gall easily and turn into their own nightmare upon trying to remove them later. Even with anti-seize.:o

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1 minute ago, Frank DuVal said:

Stainless nuts sound like a problem solver, however, stainless nuts on stainless studs (or bolts) gall easily and turn into their own nightmare upon trying to remove them later. Even with anti-seize

 

Exactly correct. You sound like you know what you are doing....................Bob

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4 hours ago, Frank DuVal said:

Stainless nuts sound like a problem solver, however, stainless nuts on stainless studs (or bolts) gall easily and turn into their own nightmare upon trying to remove them later. Even with anti-seize.

 

THIS!

 

Never, ever, ever use a stainless nut on a stainless bolt unless you are forced. If you are forced, use a LOT of anti-sieze. Stainless on mild steel is ok.

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Summershandy, please take pics and post the results on how you repaired this manifold. This is a recurring topic and would be good for others to know.

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2 hours ago, Friartuck said:

Summershandy, please take pics and post the results on how you repaired this manifold. This is a recurring topic and would be good for others to know.

I certainly will.....

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