Manifold to Exhaust Gasket choices

Mopar Exhaust Systems

  1. mag162

    mag162 Active Member

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    So this weekend The passenger side Exhaust pipe to HP manifold came loose to the point one of the flange nuts was lost and the other was also very loose.
    I noticed it right away but was a few miles from home. Anyway I found out that the exhaust shop had used 2 steel type gaskets cause I found one blown out on the lower control arm.
    I was able to get it all bolted back together but are there any better gaskets. When I slide my hand down near the joint i can still feel exhaust slipping thru.
     
  2. CBODY67

    CBODY67 Old Man with a Hat

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    With ANY exhaust gasket, the flatness of the two flanges is very important. The beaded-stainless (or metal) gaskets will work good, but there are some others which are metallic-impregnated "soft" material that can work, too. Head toward the OEM-type gaskets for best results, as the default mode. Walker Exhaust used to have some very viscous "exhaust gasket sealer" that could be used as a helper of sorts to get complete sealing, but if everything's "right", my observation is that it's more for mental support than not.

    You might also look for some exhaust flange nuts that are self-locking via a few shallow threads in the middle of the nut, which is what GM used several variations of (rather than the normal deformed lock nuts) on many OEM V-8 applications in the '80s and later. AND, find a flange-head nut when possible, for a more even clamping force.

    CBODY67
     
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  3. HWYCRZR

    HWYCRZR Senior Member FCBO Gold Member

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    I am going commando on my exhaust manifolds. No gasket between the manifold and heads. Most (‘68) were from the factory that way.
    No chance of blowing out. Need to make sure head surface and manifolds are straight.
     
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  4. CBODY67

    CBODY67 Old Man with a Hat

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    MOST OEMs did not use gaskets between their cast iron exhaust manifolds and cast iron cylinder heads. Be sure to put the "heat washers" under the exhaust manifold bolt heads, for best results. Dissimilar metals usually needed exh manifold gaskets, by observation.

    CBODY67
     
  5. 5wndwcpe

    5wndwcpe Active Member

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    Ok, the OP was talking about the exhaust pipe to manifold. You can use Remflex gaskets which seal very well, but have caused me issues in the past in that application as they require 20 lb. of torque so as to not over crush the gasket. With this low amount of torque, in that setting, the nuts come loose rather easily.

    I don't use gasket at all anymore, exhaust pipe to flange -OR- manifold to head. A bead of high temp RTV is all you need BUT follow the directions.

    Apply RTV, bolt it up snug, wait one hour, then torque to spec.
     
  6. 68PK21 440.6bbl

    68PK21 440.6bbl Old Man with a Hat

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    [​IMG]

    I've used this type of composition gasket with no problems.

    Make sure you use good grade 5 USA made bolts & nuts, also 1 flat washer and standard lockwasher on the nut side.
    A lower grade bolt of cheap or questionable metallurgy could stretch due to the heat cycling and you will end up with a blown out or leaking gasket.

    or

    You could swap out the manifolds to the gasketless bellmouth pipe late model type, (there is a reason why they went that way) but then your downpipes would need to be replaced.
     
  7. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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    Get a good quality gasket with a metal ring in it.
    The el cheapo gaskets that came with the TTi system burned out..
    You can see the difference between the two..
    cell phine may 26 2018 036.jpg
     
  8. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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    Regarding the manifold to head....yes usually no gasket.
    However,on my Newport Custom I used the manifold gaskets that doubled as heat shields between the HP logs and valve covers..
    3 years and well over 10,000 highway miles,the valve covers and gaskets are not yet cooked,LOL!
    boab september 2017 004.JPG
    boab september 2017 005.JPG
    boab september 2017 008.JPG
     
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