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Thread: Header crack -- JB Weld?

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    Default Manifold crack -- JB Weld?


    Found a crack in my pass side header (edit: MANIFOLD) the other day... I don't so much mind it as it's not too noisy yet, but I ought to try and plug it to keep the exhaust out from under the hood. Anyone used JB Weld or any other product on manifolds before? I'll look for a replacement at some point, but I'd like a short(er)-term fix now.

    Thanks!

    Chris
    Last edited by cscmc1; 06-28-2006 at 11:54 AM.

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    over worked dbarilow's Avatar
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    I dont think jb weld will stand up

    Properties (psi)
    Tensile Strength: 3960
    Adhesion: 1800
    Flex Strength: 7320
    Tensile Lap Shear: 1040
    Shrinkage: 0.0%
    Resistant to: 500 F

    Mechanics -- you can use J-B WELD with confidence. It is designed for safe, reliable, permanent repairs in engine compartments and heated environments up to 500 F. It's strong as steel and impervious to water, gasoline, chemicals, and acids. Working with J-B WELD is quick, easy, and convenient -- and saves you time, work, and money!



    I once picked up a exhaust repair putty to fill in some holes in my wifes old car that worked well it was called muffler mender by Victor products http://www.victorautomotive.net/pdfs/vic/ver1.pdf
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    Thanks for the advice! I actually hav a tube of muffler mender in the garage... I just thought I'd read somewhere that JB Weld (or something like it) was the cat's meow for exhaust work, to include manifold cracks. Obviously, at 500 degrees heat resistance that might not be the best choice.

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    Full Access Member Mr_Roboto's Avatar
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    I'll assume you are talking about an iron exhaust "manifold" which is different than a steel header.

    Iron can be welded with a stick welder and special rod for iron. I did a GM I4 manifold that was cracked so bad it was in about 15 pieces. I welded what I could reach in place, then unbolted it and welded the backside. Had I just unbolted it, it would have just fallen apart.
    1985 International rollback, 6.9L 5 speed

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    Mechanics -- you can use J-B WELD with confidence. It is designed for safe, reliable, permanent repairs in engine compartments and heated environments up to 500 F. It's strong as steel and impervious to water, gasoline, chemicals, and acids. Working with J-B WELD is quick, easy, and convenient -- and saves you time, work, and money!


    Having been a professional mechanic I would never even think of using some stuff like that on a customers car. There is a right and wrong way to fix stuff and those miracle cures are just wrong.

    Welding a crack - Right
    JB welding a crack - wrong

    inserting helicoils in stripped threads - right
    jb welding stripped threads - wrong

    etc.......

    Best advise I can give you is to do the job right the first time, it costs less in the long run as it will save you the "time, work, and money" wasted on stuff like JB weld. Then you have peace of mind the repair will last.

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    Quote Originally Posted by Mr_Roboto
    I'll assume you are talking about an iron exhaust "manifold" which is different than a steel header.

    Iron can be welded with a stick welder and special rod for iron. I did a GM I4 manifold that was cracked so bad it was in about 15 pieces. I welded what I could reach in place, then unbolted it and welded the backside. Had I just unbolted it, it would have just fallen apart.
    Indeed I am... sorry for the incorrect terminology. I've swapped headers on my Mustang so many times I just toss that term around w/o consideration. Edit made -- thanks for the clarification!

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    So it sounds like the crack, if not too bad, can just be welded, negating the need for a temp fix while I look for a replacement manifold... am I right?

    Thanks all!

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    Using the Force! Agnem's Avatar
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    If welded properly, you need not find another manifold.
    Owner, Conestoga Diesel Injection Our family - The Moose Truck - 1983 F-250HD, The Lady Moose - 1993 F-350 CC dually, The Moosestang - 1987 Bronco (1994 7.3L IDI), The Night Moose - 1995 F-150 (1984 6.9L IDI), The Iron Moose - 1986 F-250 EC, The Moose Wagon - 2002 Excursion, The Moose GT - 2008 Mustang GT 4.6L, The Moose Lodge - 1994 Wilderness 195R Serving the IDI community since 1997! Visit http://MoosePump.com or https://www.facebook.com/ConestogaDiesel

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    Full Access Member Mr_Roboto's Avatar
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    I had no problems with the one I welded for the time I owned the car.

    The worst you can do is waste the cost of a package of special welding rod.
    1985 International rollback, 6.9L 5 speed

    owner, Patriot Automotive Services, N Ridgeville

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    Thanks, guys. I'll try that route. I only have a wire feed welder, so I'll have to find someone to do this for me... but it's certainly worth a try! Maybe I'll get lucky and be able to do it w/o fighting to remove the manifold, as the crack is along the top and easy to see. D'ya think?

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    Using the Force! Agnem's Avatar
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    Might be able to get to it throught the wheel well if you remove the piece that snaps in.
    Owner, Conestoga Diesel Injection Our family - The Moose Truck - 1983 F-250HD, The Lady Moose - 1993 F-350 CC dually, The Moosestang - 1987 Bronco (1994 7.3L IDI), The Night Moose - 1995 F-150 (1984 6.9L IDI), The Iron Moose - 1986 F-250 EC, The Moose Wagon - 2002 Excursion, The Moose GT - 2008 Mustang GT 4.6L, The Moose Lodge - 1994 Wilderness 195R Serving the IDI community since 1997! Visit http://MoosePump.com or https://www.facebook.com/ConestogaDiesel

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    It will probably cost you as much if not more to get it welded by somebody who can weld cast iron properly than it will be to replace it with a used one and possibly a new one. Done right the weld is fine and you may never have to replace it, done wrong and that cast iron will crystalize and crack or shatter very quickly.

    Used manifolds for the 7.3 run anywhere from $10 - $100 each at a salvage yard and you can get a new one from Advance auto parts for $109 and Autozone can get one for $99.99

    If you want to check for a used one use www.car-parts.com It's a search through salvage yard inventories all over the states and you can locate parts in your area as well as get the prices here.

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