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Replacing Exhaust manifolds advice 1999 mercruiser 5.7 efi

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    Replacing Exhaust manifolds advice 1999 mercruiser 5.7 efi

    Hi all, I have received my new manifolds and risers and have found that the large drain plugs are not fitted to them but have been provided, I can't seem to find any info and how to install these, do I need to put some sort of sealer or plumbers tape on these when fitting? I also need to add new drain elbows so will these need to be sealed also?
    Also should I remove all paint from the mating surfaces where the gaskets go?
    Last but not least I'm looking for the torque settings for both the risers and manifold bolts.
    As usual thanks for all the help.
    Regards William.
    1999 Bayliner Ciera 2655 Mercrusier 5.7 EFI Alpha One

    #2
    Please post a little info concerning your engine, year, model, hp !
    Be good, be happy, for tomorrow is promised to no man !

    1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

    '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

    Manalapan N.J

    Comment


      #3
      Originally posted by Chief_Alen View Post
      Please post a little info concerning your engine, year, model, hp !
      sorry my bad, its mercruiser 5.7 efi 1999
      1999 Bayliner Ciera 2655 Mercrusier 5.7 EFI Alpha One

      Comment


        #4
        I use teflon tape or aviation gasket sealer from a gasket. Either one will work on the fittings. As for the drain elbow it goes on the bottom of the manifold. You will need to look at what you have as there are a few different variations of cooling systems. The drain elbows themselves need to be sealed the actual plug does not need to be sealed.

        as for toque setting I think its 28 ft lbs but you need to find a more reliable spec not what someone says here. I don't want to be responsible for broken or leaking bolts.

        1989 Avanti 3450 Sunbridge
        twin 454's
        MV Mar-Y-Sol
        1979 Bayliner Conquest 3150 hardtop ocean express.
        Twin chevy 350's inboard
        Ben- Jamin
        spokane Washington

        Comment


          #5
          Originally posted by yachtman View Post
          I use teflon tape or aviation gasket sealer from a gasket. Either one will work on the fittings. As for the drain elbow it goes on the bottom of the manifold. You will need to look at what you have as there are a few different variations of cooling systems. The drain elbows themselves need to be sealed the actual plug does not need to be sealed.

          as for toque setting I think its 28 ft lbs but you need to find a more reliable spec not what someone says here. I don't want to be responsible for broken or leaking bolts.
          Mercruiser manual states 25 ft lbs for the torque. I agree with Teflon tape or aviation gasket sealer for the plugs and elbows.
          1997 Maxum 2400 SCR 5.7LX Bravo II

          Mike

          Comment


            #6
            Originally posted by Nauti_Mike View Post

            Mercruiser manual states 25 ft lbs for the torque. I agree with Teflon tape or aviation gasket sealer for the plugs and elbows.
            And that is why I say don't trust what iz said about torque values. My 350 chevy marine power manual says 28 but every engine brand and type can be different even when referring to same size bolts.
            1989 Avanti 3450 Sunbridge
            twin 454's
            MV Mar-Y-Sol
            1979 Bayliner Conquest 3150 hardtop ocean express.
            Twin chevy 350's inboard
            Ben- Jamin
            spokane Washington

            Comment


              #7
              http://www.torkspec.com/torkspecme.a...-5.7L-350ci-V8

              I like to check for a true square mating surface with a metal ruler.

              Yes to the aviation form a gasket, will not melt.
              Be good, be happy, for tomorrow is promised to no man !

              1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

              '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

              Manalapan N.J

              Comment


                #8
                I sanded the spray paint off the machined mating surfaces and sprayed the red tacky stuff on all surfaces including gaskets.
                Make sure you get all the old gasket stuff off your heads. I had to redo my manifold to head gasket twice on my starboard side due to a valve tick from a small exhaust leak. Spent many hours sanding the burnt/rusted old exhaust manifold off. My manifolds were a b!a?ch to get off they were rusted on so bad. Luckily the 2859 is a very pleasurable boat to work on and you can stand in the engine bay.
                Esteban
                Huntington Beach, California
                2018 Element 16
                Currently looking for 32xx in South Florida
                Former Bayliners: 3218, 2859, 2252, 1952

                Comment


                  #9
                  I've always used a 1" wide flat file to clean off mating surfaces, and work across the entire surface rather than staying on one spot until it's clean. The entire file must remain in contact with the surface being worked on to ensure that you have a flat surface. A straightedge then then confirm your results.Using sandpaper may work, but it's difficult to keep it to keep it perfectly flat across the entire surface.. You really need a perfectly flat surface for these parts to seal well.
                  Bob Hawes.
                  Kelowna, B.C.
                  1998 Trophy 2052 WA
                  4.3 Vortec, A1 G2

                  Comment


                    #10
                    I read somewhere, not sure where, not to use anything on the plugs. They are concerned about over tightening and cracking the manifold. I guess the teflon acts as a lubricant which can lead to overtightening. I think it can be used but do not get carried away tightening them up.

                    The main thing is to check the manifolds for the first month or so after heating and cooling. You will find they need tightening.
                    1979 32 Uniflite Sport Sedan twin 270 crusaders
                    2003 Bayliner 2152 210 Classic 5.0 mercruiser - sold
                    I wish I knew now what I didn't know then

                    Comment


                    • builderdude
                      builderdude
                      BOC Site Team
                      builderdude commented
                      Editing a comment
                      Absolutely re torque the bolts after the first and second heat cycles. Wouldn’t hurt to check them even after that.

                    #11
                    Originally posted by Morecoffee View Post
                    I read somewhere, not sure where, not to use anything on the plugs. They are concerned about over tightening and cracking the manifold. I guess the teflon acts as a lubricant which can lead to overtightening. I think it can be used but do not get carried away tightening them up.

                    The main thing is to check the manifolds for the first month or so after heating and cooling. You will find they need tightening.
                    Thanks, have you any idea of a torque value for these, I really dont want to risk cracking the manifolds.
                    1999 Bayliner Ciera 2655 Mercrusier 5.7 EFI Alpha One

                    Comment


                      #12
                      look at the link i put up
                      Be good, be happy, for tomorrow is promised to no man !

                      1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

                      '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

                      Manalapan N.J

                      Comment


                        #13
                        Originally posted by Chief_Alen View Post
                        look at the link i put up
                        Sorry I mean the torque settings for the plugs into the exhaust manifolds and risers?
                        1999 Bayliner Ciera 2655 Mercrusier 5.7 EFI Alpha One

                        Comment


                          #14
                          Originally posted by william86 View Post

                          Sorry I mean the torque settings for the plugs into the exhaust manifolds and risers?
                          Tighten then till they are snug; these are plugs not fasteners.
                          1997 Maxum 2400 SCR 5.7LX Bravo II

                          Mike

                          Comment


                            #15
                            Originally posted by william86 View Post

                            Sorry I mean the torque settings for the plugs into the exhaust manifolds and risers?
                            Tighten so they won't leak, personally I'd use thread tape and/or pipe dope.
                            Dave
                            Edmonds, WA
                            "THE FIX"
                            '93 2556
                            Carbureted 383 Vortec-Bravo II 2.0:1 18 1/4x19 P

                            The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
                            Misc. projects thread
                            https://www.baylinerownersclub.org/f...56-gctid789773

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