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Thread: Manifold gasket

  1. #1

    Default Manifold gasket

    What is everyone's preferred manifold gasket? My new manifold came with the silver colored type but the old manifold gasket was more of a fiber looking gasket. Don't want ANY leaks!

  2. #2
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    Default Re: Manifold gasket

    What manifold? Intake or exhaust?
    Jack
    Mass.

  3. #3

    Default Re: Manifold gasket

    Quote Originally Posted by kghost View Post
    What manifold? Intake or exhaust?
    It's a barr marine combo for a 3.0.

  4. #4
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    Default Re: Manifold gasket

    I think that you'll be safe to use what Barr provided.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  5. #5

    Default Re: Manifold gasket

    Quote Originally Posted by RicardoMarine View Post
    I think that you'll be safe to use what Barr provided.
    Well I don't know if they provided it or the place I purchased it from did. What do you guys use and why?

  6. #6
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    Default Re: Manifold gasket

    For exhaust manifold either type will work. The metallic one is susceptible to corrosion but if your not in salt water it will be fine.
    Jack
    Mass.

  7. #7

    Default Re: Manifold gasket

    Quote Originally Posted by kghost View Post
    For exhaust manifold either type will work. The metallic one is susceptible to corrosion but if your not in salt water it will be fine.
    Okay thanks. It's in brackish water so I'm going with the fiber one.

  8. #8
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    Default Re: Manifold gasket

    Seawater won't be coming into contact with the gasket so that's not really a thing to worry about. The metal faced ones tend to not stick to the mating surface so that removal is easier but again it's such a fine line that it doesn't really matter. I like the stainless steel multi layer gaskets but they are really expensive.
    Practicing the ancient art of ren-ching

  9. #9
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    Default Re: Manifold gasket

    Click image for larger version. 

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    When I did my 2 piece exhaust conversion (from the OMC one piece batwings) with Barr exhaust I used the Barr elbow to manifold gaskets coated with Permatex Aviation (actually a Barr tech advised that) and no leaks 2 years later.

  10. #10
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    Default Re: Manifold gasket

    Agreed. For some fool reason I read some literature that warns against using sealer on these gaskets. (I assume the idea is to prevent excessive silicone plugging the outlet holes?) From my experience the joint will leak without smearing both sides of the gasket with a sealer.

    Good luck!

    Jeff

  11. #11
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    Default Re: Manifold gasket

    Quote Originally Posted by fastjeff View Post
    I read some literature that warns against using sealer on these gaskets.
    Jeff

    not sure where this information comes from, but in the "automotive" world, specifically 454 engines in heavy duty applications, they recommend that the exhaust manifolds be surfaced and silicone used in place of gaskets, as this allows for a better heat transfer which gives longer manifold life without cracking, warping or leaking..... in a marine application, the engine isnt getting as hot and isnt getting road spray on it, but i cant see the downside to using silicone in place of a gasket or with a gasket...
    on marine engines with closed loop cooling I use regular automotive exhaust gaskets (NO silicone) without any failures, but i also always surface the manifolds, as its very surprising how warped even new exhaust manifolds can be.

    the use of silicone on the exhaust manifold gasket probably has very little effect either way...

    in all automotive engines we deal with that has cast exhaust manifolds, we dont use gaskets at all, but only silicone as it lowers the chance of an exhaust leak..
    Last edited by centerline; 02-01-2020 at 04:13 PM.

  12. #12
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    Default Re: Manifold gasket

    Quote Originally Posted by centerline View Post
    <br>
    <br>
    not sure where this information comes from, but in the "automotive" world, specifically 454 engines in heavy duty applications, they recommend that the exhaust manifolds be surfaced and silicone used in place of gaskets, as this allows for a better heat transfer which gives longer manifold life without cracking, warping or leaking..... in a marine application, the engine isnt getting as hot and isnt getting road spray on it, but i cant see the downside to using silicone in place of a gasket or with a gasket... on marine engines with closed loop cooling I use regular automotive exhaust gaskets without any failures, but i also always surface the manifolds, as its very surprising how warped even new exhaust manifolds can be..<br><br>&nbsp;the use of silicone on the exhaust manifold gasket probably has very little effect either way...<br>
    <br>
    in all automotive engines we deal with that has cast exhaust manifolds, we dont use gaskets at all, but only silicone as it lowers the chance of an exhaust leak
    1. This is strictly a Marine Application.

    2. Auto experience such as yours does not matter here.

    3. Your automotive application uses TWO (2) bolts/studs per exhaust hole...............Mercruiser does NOT.

    4. USE A GASKET. What type is your choice!
    Jack
    Mass.

  13. #13
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    Default Re: Manifold gasket

    Quote Originally Posted by kghost View Post
    1. This is strictly a Marine Application.

    2. Auto experience such as yours does not matter here.

    3. Your automotive application uses TWO (2) bolts/studs per exhaust hole...............Mercruiser does NOT.

    4. USE A GASKET. What type is your choice!
    I agree... but my point is that it shouldnt make a bit of difference either way. as long as the surfaces dont warp and remain sealed is all that matters.

  14. #14
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    Default Re: Manifold gasket

    The suggestions came from Barr and OSCO, as I recall. Their idea, apparently, is to keep excessive silicone plugging up the outlet holes in the elbow (where water finally meets the exhaust). I've seen one side manifold overheating when the holes on that side plugged up.

    That said, water leaking into the motor through the exhaust ports is a far more threatening possibility. I seal the gaskets with a smear of silicone on each side and wait a while for it to set before firing the motor up.

    Jeff

  15. #15
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    Default Re: Manifold gasket

    Quote Originally Posted by fastjeff View Post
    The suggestions came from Barr and OSCO, as I recall. Their idea, apparently, is to keep excessive silicone plugging up the outlet holes in the elbow (where water finally meets the exhaust). I've seen one side manifold overheating when the holes on that side plugged up.

    That said, water leaking into the motor through the exhaust ports is a far more threatening possibility. I seal the gaskets with a smear of silicone on each side and wait a while for it to set before firing the motor up.

    Jeff
    its all in how one uses a product that can make the difference between being a winner or being a loser..... and the manufactures do NOT want to be responsible for stupid mistakes made by in experienced "mechanics" who think more is better....

  16. #16
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    Default Re: Manifold gasket

    ..."its all in how one uses a product that can make the difference"

    Damn straight!

    Jeff

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