Cracked 318 cylinder head

1966 -1967 Mopars

  1. Oxide Fox

    Oxide Fox Member

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    Uhg! Tried to extract a broken bolt from my 67 charger’s 318 and cracked the head. I have taken an engine rebuild class at a community collage... a decade ago. I don’t think I’m capable and/or willing to deal with measurements, clearances, lash, push rods, lapping and all that technical witchcraft. What are some simple solutions for me?

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  2. RJRENTON

    RJRENTON FBBO Gold Member FBBO Gold Member

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    Without being totally facious.....buy a new / used head casting or a complete ready to install head Or It may be possible to braze the hole closed and re-drill the it and use a stud instead of a bolt. Because the section is thin I do not think welding and redrilling would be possible even with a nickel alloy rod....but others may have additional suggestion or fixes. I do not think a heli coil will work because of the location. Just my opinion of course
    BOB RENTON
     
  3. Bad B-rad

    Bad B-rad Well-Known Member

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    You can do what some call cold welding, some call pinning.
    Hard to describe, I will do my best:
    You have to get some cast iron pipe plugs/ or bolts.
    The size depends on the hole you are repairing.
    Drill the bolt hole out so you can tap it and install the pipe plug, some people use tape on the threads, then cut the plug/bolt off almost even with the head casting.
    Drill your next hole so that half of the hole will be on the plug you installed and the other half will end up on the cracked area, run the tap threw it, thread in next plug, and cut remainder off almost flush.
    drill next hole half on your 2nd pipe plug, and half on crack.
    You repeat this until the crack is 100% gone, in both directions.
    Then grind repaired area 100% flush, install your manifold or header, or use the gasket, to locate where to drill the final hole, that you will tap in correct size of manifold bolt. that broke in first place.

    I know it takes a lot of time but its not hard work, and I have seen it done to combustion chamber of cylinder heads and no issues.

    here is a site with instructions, once there go down to pinning :
    https://www.enginebuildermag.com/2012/01/cylinder-head-repair-methods/
     
    Last edited: Jul 2, 2020
  4. RJRENTON

    RJRENTON FBBO Gold Member FBBO Gold Member

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    Interesting concept......from the original photo, it appears that there is almost no "meat" or area to install multiple cast plugs and redrilling on the original centerline.....but nothing ventured nothing gained......not sure how close to coolant passages....hard to see clearly even zoomed in close.
    BOB RENTON
     
  5. Bad B-rad

    Bad B-rad Well-Known Member

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    If I was gonna use that technique on that crack, I would cut the plugs off a touch higher then the manifold mating surface, and once finished, grind it into shape. But maybe leaving the repair a bit higher then original head surface.

    Honestly anytime I have seen this done it was on very expensive equipment heads, or rare engine parts.

    I have read about a bunch of JB weld style epoxy that many people swear work flawlessly.
    I have NEVER had luck with this, myself.
    Try a quality epoxy, if that doesn't work, move on to pinning/ cold weld.

    Either way it dose suck, best of luck!
     
  6. megaivtes

    megaivtes Well-Known Member

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    aren't the outer bolts on the head into the water jacket?
     
    • Agree Agree x 1
    • Bad B-rad

      Bad B-rad Well-Known Member

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      I don't know, as I have honestly never messed with LA engines, besides maintenance.
      I am Bradly-Big block, Lol!!!
       
    • Mark Barnes

      Mark Barnes Well-Known Member

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      New head will solve any problems you're going to have down the road. Just do it now. There's about a million castings like that laying around everywhere. I'd be afraid of the location of that crack.
       
    • 451Mopar

      451Mopar Well-Known Member

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      Not sure how hard it is to locate the closed chamber '67 heads (273 & 318), but I would look for a replacement head.
      The end bolt holes do go into the water jacket.

      If you plan to repair the crack, you need to find out how far it really goes.
      I would weld repair the cracks, but the head would still have to be removed, crack ground out and cleaned very well, Casting pre-heated, then welded with nickle rod.
      https://www.lincolnelectric.com/en-us/support/welding-how-to/Pages/welding-cast-iron-detail.aspx

      The bolt hole will likely get welded up (at least partly) in the process, so it will need to be re-drilled and tapped.
       
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