Tom of heat on end of manifold???

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  • southcoasting
    Senior Member
    • Nov 2011
    • 141

    Tom of heat on end of manifold???

    I had replaced my manifold after my first was completely toast and spitting large amounts of antifreeze into my dry exhaust section...

    Well, since running the engine for a a short bit on this end, Inma seeing my paint has baked off on the end of the manifold...I have seen other A4s develop more rust around than normal and think the extra heat here might normal???

    I think maybe having excess antifreeze in exhaust section may have back flowed and just pooled there and then burned off to make it hotter than the rest of manifold and thus causing this burn off of paint?

    I am also starting to think that my Por15 engine paint is not that good as there is a good amount of discoloring...my fwc engine runs between 140 and 180 depending on rpm...

    Thoughts on this?
    Attached Files
    Last edited by southcoasting; 09-12-2020, 07:35 AM.
    1971 Tartan 34C Sloop "NOVA LUNA", Rebuilt (2019) Fresh Water Cooled A4 (Bought boat in 2014)
    1968 Tartan 27 Yawl "Destinada", rebuilt Old Lyme freshwater A4 (Sold boat in 2014)
  • Al Schober
    Afourian MVP
    • Jul 2009
    • 2006

    #2
    You may have an air pocket trapped in the high end of the manifold. Some of us have modified the coolant flow to go from the t'stat housing then into the LOW end of the manifold. Manifold outlet is then at the high end.

    Comment

    • Dave Neptune
      Afourian MVP, Professor Emeritus
      • Jan 2007
      • 5044

      #3
      The exhaust runs out PAST and UNDER the water jacket so some discoloration due to heat is normal. The other end may be toasty too.

      It also looks like you may have a slight leak coming from the mounting stud. Did you seal the studs in?

      Look up "ubiquitous" hot spot on this site.

      Dave Neptune

      Comment

      • romantic comedy
        Afourian MVP
        • May 2007
        • 1912

        #4
        It looks like an exhaust leak that is burning off the paint.

        Comment

        • W2ET
          Former Admin
          • Oct 2008
          • 170

          #5
          Originally posted by romantic comedy View Post
          It looks like an exhaust leak that is burning off the paint.
          If so, that's not good.

          Bill

          Comment

          • southcoasting
            Senior Member
            • Nov 2011
            • 141

            #6
            Originally posted by romantic comedy View Post
            It looks like an exhaust leak that is burning off the paint.
            Do you mean the lower exhaust portion may have a slight crack and thus is leaking exhaust fumes? I seen some fumes coming out of there but it seemed to be coming from the leak at the stud...

            Yeah, could be the excess antifreeze that was already in the exhaust pipe that pooled back in and is burning off there?

            There was a leak of antifreeze there on that stud that I mentioned...I was assuming it was coming from the excess a/f already in the exhaust pipe from the previous bad manifold...

            I will keep an eye on it...When I installed the studs, I had used the permatex aviation stuff but maybe it needs to be re-seated...will keep an eye on it...
            Last edited by southcoasting; 09-12-2020, 07:34 AM.
            1971 Tartan 34C Sloop "NOVA LUNA", Rebuilt (2019) Fresh Water Cooled A4 (Bought boat in 2014)
            1968 Tartan 27 Yawl "Destinada", rebuilt Old Lyme freshwater A4 (Sold boat in 2014)

            Comment

            • southcoasting
              Senior Member
              • Nov 2011
              • 141

              #7
              Originally posted by Al Schober View Post
              You may have an air pocket trapped in the high end of the manifold. Some of us have modified the coolant flow to go from the t'stat housing then into the LOW end of the manifold. Manifold outlet is then at the high end.
              Interesting...the other end would be the high end...how would that look like? Would it block the access to plugs, etc or I assume you are running it in a way that it is not running across the head?
              1971 Tartan 34C Sloop "NOVA LUNA", Rebuilt (2019) Fresh Water Cooled A4 (Bought boat in 2014)
              1968 Tartan 27 Yawl "Destinada", rebuilt Old Lyme freshwater A4 (Sold boat in 2014)

              Comment

              • southcoasting
                Senior Member
                • Nov 2011
                • 141

                #8
                Originally posted by W2ET View Post
                If so, that's not good.

                Bill
                Elaborate more please?
                1971 Tartan 34C Sloop "NOVA LUNA", Rebuilt (2019) Fresh Water Cooled A4 (Bought boat in 2014)
                1968 Tartan 27 Yawl "Destinada", rebuilt Old Lyme freshwater A4 (Sold boat in 2014)

                Comment

                • W2ET
                  Former Admin
                  • Oct 2008
                  • 170

                  #9
                  I was just thinking that you don't want exhaust gases exiting anywhere other than out the transom, for safety reasons. I'd worry about CO and the prospect of something in the vicinity overheating.

                  Bill

                  Comment

                  • capnward
                    Afourian MVP
                    • Aug 2012
                    • 335

                    #10
                    Looking closely at your photo, I think I see a small hole in your freeze plug. If you are going to continue running it, I suggest you get a CO alarm.

                    Comment

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