Exhaust manifold leak...

Discussion in ''Da Nailhead' started by 1966buickgs, May 19, 2016.

  1. 1966buickgs

    1966buickgs 1966buickgs

    What size is the gasket between the lower part of the exhaust manifold that connects to the exhaust pipe? Oh an is it true if I use exhaust manifold gaskets on my stock manifolds they will cause cracks? Thank you
  2. Rivman

    Rivman Senior Ottawa Buick Guy

    Not sure about a '66, but in '68 there is no gasket between the down pipe and exhaust manifold, the pipe is flared and is snubbed up to the manifold via a flange and bolts on the manifold studs. My 430 exhaust manifolds came from the factory without any gaskets and one still cracked !
    Someone here has a set of '66 manifolds for sale (...Doug Paine). :TU:
  3. 1966buickgs

    1966buickgs 1966buickgs

    Ok thanks I could not remember if there were gaskets on that lower part of the manifolds when we pulled the motor months ago. I do remember having gaskets on the upper part of the manifold that bolts to the heads but I remember reading something on Russ Martin's sight that says don't use the with factory manifolds like mine cause the gaskets will cause cracks. How does that happen? An if some were on there before with the french locks on the bolts too looked all factory to me,don't wana take a chance an crack anything though after this rebuild especially, wondering how that could happen.Oh an this is a 401 nailhead. Thank you
  4. bhambulldog

    bhambulldog 1955 76-RoadmasterRiviera

    Gaskets on the manifold interfere with the heat transfer .
    With no gasket, the head absorbs heat off the manifold, keeping the manifold from getting too hot.

    Sent from my iPhone using Tapatalk
  5. telriv

    telriv Well-Known Member

    Have the manifold head mating surfaces re-ground for a proper sealing surface. NO GASKETS REQUIRED!!!!
  6. bhambulldog

    bhambulldog 1955 76-RoadmasterRiviera

    That's what we did fifteen years ago, Tom.
    No leaks today.

    In 1970, when Dad bought the Roadmaster, it had a cracked manifold , and gaskets on both manifolds.

    Some thirty years later;
    After finding a pair of good manifolds, Dad had them milled to meet up with heads.

    No gaskets
    No leaks ,for seventeen years now.
  7. 1966buickgs

    1966buickgs 1966buickgs

    Thank you for the information!
  8. Aussie V8

    Aussie V8 Well-Known Member

    Tom , your PM mail box is full.

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