Header leak nightmare

Mopar Exhaust Systems

  1. Smokinnjokin

    Smokinnjokin Well-Known Member

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    Alright, so I am finally ready to sit back and ask the experts for help.

    I put some summit headers (g09040) on my '67 satellite with a smog 360, and couldn't get them to seal. Took back off 4+ times, tried percy's gaskets, fel-pro, red/black/copper rtv's, the works. Loud ass, leak, sounded like it was coming from everywhere. Every. F'ing. Time.

    I worried that perhaps my smog hole plug job (had a couple tap breaks, plugged w/j-b weld) wasn't complete, and that was the leak i was hearing. No indication on the gaskets of any smoke/impression by the smog ports, they still looked plugged, nothing appearing to come out under the header flange. I can't be 100% sure because the flange covers them, but i don't think they are the culprit.

    SOOO. I finally gave up and dropped $$$$ on TTI headers and full system. I wasn't crazy about the ground clearance on the summit headers anyway. Great product, easy install but i still have the same loud ass leak sound, seems to be coming from everywhere. Can't isolate to one side or the other. Currently have Remflex gaskets, w/no sealant. 20 ft/lbs as recommended.

    They LOOK sealed. The gasket is crushed. Spraying soapy water around while running, i see no bubbles. Where the hell is the sound coming from? It is such a loud racket I can barely hear the exhaust note coming out 2.5" H-pipe duals w/dynomax. It sounds as if somehow one or two cylinders is way louder than the others and the sound is just echoing in the headers.

    Questions? Recommendations for next steps?
     
  2. silversedan

    silversedan Well-Known Member

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    was it quiet before you put the first headers on, or is this a new start up?
     
  3. tmaleck

    tmaleck FBBO Gold Member FBBO Gold Member

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    Is this your first car with headers?
     
  4. Smokinnjokin

    Smokinnjokin Well-Known Member

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    Not my first b-body with headers, have put them on several (cheap shitty headers i might add, headman and cheapo summit!) small blocks that sealed right up first try.

    Car ran great and was whisper-quiet with stock cast iron manifolds and dual 2' compression-bend exhaust. Head surfaces are flat and clean.
     
  5. Bad Sport

    Bad Sport Well-Known Member

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    I you haven't already, cut a piece of hose about 3 to 4 foot long. Hold one end to your ear and move the other end around the header flange. If there is a leak there, it should amplify itself in the hose.
     
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    • WileERobby

      WileERobby Well-Known Member

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      Does it have EGR ?
       
    • Smokinnjokin

      Smokinnjokin Well-Known Member

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      Not sure... don't think so. Its a mid 70's smog motor with stock intake manifold and edelbrock performer carb.
       
    • Smokinnjokin

      Smokinnjokin Well-Known Member

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      If i identify a spot thats leaking, is it ok to keep cranking down on the remflex gasket? Currently 20-25 ft-lbs, i got the impression that if you need more torque something is probably seriously wrong.
       
    • dryheat

      dryheat FBBO Gold Member FBBO Gold Member

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      Not sure if this is the case but in the mid/late-70's I helped a friend put headers on a small block Volare. We had to tap and plug the small smog ports at the bottom of each exhaust port on the heads. It was very difficult to do with the motor still in the car.
       
    • Smokinnjokin

      Smokinnjokin Well-Known Member

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      I don't think they are the issue, but not 100% sure... i had some shitty tap jobs that were not perfectly matching the angle of the passage, and some that i put JB weld in, but no obvious indicators of a leak from there. PLUS, the remflex gasket completely covers these holes combined with the very thick TTI flange seems like that would make up for any residual leak that may be left and at least muffle the sound.

      The sound I am hearing is really echoing in the header tubes. I'm gonna check with a stethoscope tonight but it really sounds like its coming from everywhere towards the back/underneath/header tubes.

      Is it possible that some other engine noise (clearly something wrong) is getting amplified by the headers? Starts and idles fine, revs cleanly thru the rev range, feels strong. Exhaust note (what I can hear over the racket) sounds healthy.
       
    • INTMD8

      INTMD8 Well-Known Member

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      What I do is get a silicone coupler (or rubber I suppose from hardware store) and adapt it to the outlet of a leakdown tester. Pressurize the system at the exhaust tip. (block the other) with shop air and you can check it all for leaks without burning yourself
       
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      • YY1

        YY1 Well-Known Member

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        Good point about smog/air ports on 80's heads (302, etc).

        I've also sen the pipes hit or hang up on something (motor mount, steering, starter) and not allow the bottom of the flange to seal.
         
      • Smokinnjokin

        Smokinnjokin Well-Known Member

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        There is some tension on the headers from the exhaust system, not quite perfect alignment with the flanges and adapters and they don't perfectly line up until the bolts are tightened. Enough not to let the flange seal? Seems unlikely, tti headers are VERY thick tubing and the flanges are crazy thick so i'm thinking not.

        Also, I made sure to get perfect alignment of gasket, header and ports (due to the extra-large bolt holes in flange that allow a lot of movement) using blind pins during install. The pipes aren't hitting anything.
        This is my next step. I usually use a shop-vac on blow setting and tape it up to the exhaust pipe real good, put the vac as far away so no noise.
         
      • Smokinnjokin

        Smokinnjokin Well-Known Member

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        Well, hold on to your butts. Its not a damn exhaust leak at all. Just went around with the stethescope and the sound was coming from the bellhousing. Popped of the inspection cover, something is hitting the flywheel. the noise is echoing EXACTLY like an exhaust leak in there.

        I have swapped b-body headers like 6 times, gasket scrape drain coolant and clean... for no damn reason.
        Now to let the car cool down so i can figure out WTF is hitting my flywheel.
         
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        • Smokinnjokin

          Smokinnjokin Well-Known Member

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          UPDATE! The damn bellhousing dust/inspection cover got bent a tiny bit somehow and was flapping against the flexplate. Even staring straight at it watching it happen, it still sounds exactly like a header leak. No wonder the sound seemed to be coming from everywhere.
           
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          • 1967coronet440

            1967coronet440 Well-Known Member

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            Been there, done that. Mine was very distinct though knew right away it wasn’t exhaust at all. Glad you got it figured it out
             
          • khryslerkid

            khryslerkid FBBO Gold Member FBBO Gold Member

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            Well you're an expert on installing headers now!

            Fun stuff, glad it was a simple fix :thumbsup:
             
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            • 451Mopar

              451Mopar Well-Known Member

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              Back around 1990, I bought Blackjack alumacoat headers for a 383. Could not get them to seal (or that's what I thought?)
              After taking them off for ?? times, I noticed the tubes were not welded all the way around the flange. Returned those and got the more expensive Hooker headers.
              FWIW, I think the RemFlex header gaskets seal where most others wont.
               
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