Header crack -- JB Weld?

Discussion in '6.9L IH & 7.3L IDI Diesels' started by cscmc1, Jun 28, 2006.

  1. cscmc1

    cscmc1 Full Access Member

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    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: Jun 28, 2006
  2. dbarilow

    dbarilow over worked

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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
     
  3. cscmc1

    cscmc1 Full Access Member

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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.
     
  4. Mr_Roboto

    Mr_Roboto Full Access Member

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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.
     
  5. tonkadoctor

    tonkadoctor Full Access Member

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    :rotflmao :rotflmao :rotflmao

    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.
     
  6. cscmc1

    cscmc1 Full Access Member

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    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!
     
  7. cscmc1

    cscmc1 Full Access Member

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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!
     
  8. Agnem

    Agnem Using the Force! Staff Member Supporting Member

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    If welded properly, you need not find another manifold.
     
  9. Mr_Roboto

    Mr_Roboto Full Access Member

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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.
     
  10. cscmc1

    cscmc1 Full Access Member

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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?
     
  11. Agnem

    Agnem Using the Force! Staff Member Supporting Member

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    Might be able to get to it throught the wheel well if you remove the piece that snaps in.
     
  12. tonkadoctor

    tonkadoctor Full Access Member

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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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