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exhaust design ?

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  • cjecje2
    My exhaust spud is under the stern and almost vertical. Sometimes the engine wouldn t start and I would find the sparkplug gaps shorted with water drops.
    Message 1 of 13 , Apr 27, 2013
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      My exhaust spud is under the stern and almost vertical. Sometimes the engine wouldn't start and I would find the sparkplug gaps shorted with water drops. Apparently when the boat would hobby-horse at the dock water would be forced in, the exhaust would fill, and eventually water would get into the engine. I felt that the hot-portion of the exhaust riser loop was too low.

      So I repiped it and put the riser loop as high up into the bridge deck as possible - about a foot or more higher than before.

      The previous exhaust pipe was un-supported after leaving the exhaust manifold and the 24" lever-arm it formed seemed like a very weak arrangement. In fact; the nipple into the exhaust manifold flange was already cracked about 50% when I removed it.

      So I also mounted a piece of 1 5/8" Unistrut under the bridge deck and used a conduit clamp to secure the top of the new exhaust riser to the unistrut.

      The top of the riser now consists of these items: a vertical pipe nipple up into a 90º ell - a 4" pipe nipple to form the horizontal - a 90º street ell with the male end facing down - and then a tee. The side connection of that tee is where the water is injected.

      I wrapped the hot portion of the exhaust pipe with standard 1 1/2" 'exhaust wrap' tape from the hot rod store. The exhaust was previously wrapped and I re-used that material but as the piping is now longer I bought another 50' of exhaust wrap to finish it. The pieces I cut were longer than actually required so much of the exhaust is now double-layer wrapped.

      Nonetheless; the bridge deck gets hot and the heads of the carriage bolts which secure the unistrut get too hot to touch.

      What else can I use to insulate the hot portion of the exhaust? The thickness doesn't matter as I can get pretty much any size conduit clamp.

      stephen
      -----------
    • cchl74
      The best way to separate exhaust heat from the rest of the hull is with some sort of air gap, or at least minimum direct contact between the pipe and the
      Message 2 of 13 , Apr 27, 2013
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        The best way to separate exhaust heat from the rest of the hull is with some sort of air gap, or at least minimum direct contact between the pipe and the mounting hardware. Heat is transferred either by direct conduction or radiant heat, (IR). Is there some way you can pack the clamped areas with ss scrubbies or something to reduce the direct heat path from pipe to clamp? The heat tape is a help against radiant heat loss but it is still conducting too much heat.  A narrower clamp would help. True, non conductive heat shields usually involve ceramics and have NASA part numbers.


                Bruce K
                Challenger # 74, "Ouroboros"
                Los Lunas, NM



        My exhaust spud is under the stern and almost vertical. Sometimes the engine wouldn't start and I would find the sparkplug gaps shorted with water drops. Apparently when the boat would hobby-horse at the dock water would be forced in, the exhaust would fill, and eventually water would get into the engine. I felt that the hot-portion of the exhaust riser loop was too low.

        So I repiped it and put the riser loop as high up into the bridge deck as possible - about a foot or more higher than before.

        The previous exhaust pipe was un-supported after leaving the exhaust manifold and the 24" lever-arm it formed seemed like a very weak arrangement. In fact; the nipple into the exhaust manifold flange was already cracked about 50% when I removed it.

        So I also mounted a piece of 1 5/8" Unistrut under the bridge deck and used a conduit clamp to secure the top of the new exhaust riser to the unistrut.

        The top of the riser now consists of these items: a vertical pipe nipple up into a 90º ell - a 4" pipe nipple to form the horizontal - a 90º street ell with the male end facing down - and then a tee. The side connection of that tee is where the water is injected.

        I wrapped the hot portion of the exhaust pipe with standard 1 1/2" 'exhaust wrap' tape from the hot rod store. The exhaust was previously wrapped and I re-used that material but as the piping is now longer I bought another 50' of exhaust wrap to finish it. The pieces I cut were longer than actually required so much of the exhaust is now double-layer wrapped.

        Nonetheless; the bridge deck gets hot and the heads of the carriage bolts which secure the unistrut get too hot to touch.

        What else can I use to insulate the hot portion of the exhaust? The thickness doesn't matter as I can get pretty much any size conduit clamp.

        stephen
        -----------

      • niebur32
        Hey Stephen, I don t quite parse your exhaust construction. But do I read it right that you fastened your exhaust to the boat with an unistrut (I had to google
        Message 3 of 13 , Apr 27, 2013
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          Hey Stephen, I don't quite parse your exhaust construction. But do I read it right that you fastened your exhaust to the boat with an unistrut (I had to google that)? Is that a good idea, shouldn't the exhaust move with the engine, rather than the boat?

          I rebuilt my exhaust last year. Come by once you are in your new place and have a look at the exhaust of the good ship Tavernier. The previous version lasted >10 years, at which point the black pipe was rusted out.h

          --Ernst

          --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@...> wrote:
          >
          >
          > My exhaust spud is under the stern and almost vertical. Sometimes the engine wouldn't start and I would find the sparkplug gaps shorted with water drops. Apparently when the boat would hobby-horse at the dock water would be forced in, the exhaust would fill, and eventually water would get into the engine. I felt that the hot-portion of the exhaust riser loop was too low.
          >
          > So I repiped it and put the riser loop as high up into the bridge deck as possible - about a foot or more higher than before.
          >
          > The previous exhaust pipe was un-supported after leaving the exhaust manifold and the 24" lever-arm it formed seemed like a very weak arrangement. In fact; the nipple into the exhaust manifold flange was already cracked about 50% when I removed it.
          >
          > So I also mounted a piece of 1 5/8" Unistrut under the bridge deck and used a conduit clamp to secure the top of the new exhaust riser to the unistrut.
          >
          > The top of the riser now consists of these items: a vertical pipe nipple up into a 90� ell - a 4" pipe nipple to form the horizontal - a 90� street ell with the male end facing down - and then a tee. The side connection of that tee is where the water is injected.
          >
          > I wrapped the hot portion of the exhaust pipe with standard 1 1/2" 'exhaust wrap' tape from the hot rod store. The exhaust was previously wrapped and I re-used that material but as the piping is now longer I bought another 50' of exhaust wrap to finish it. The pieces I cut were longer than actually required so much of the exhaust is now double-layer wrapped.
          >
          > Nonetheless; the bridge deck gets hot and the heads of the carriage bolts which secure the unistrut get too hot to touch.
          >
          > What else can I use to insulate the hot portion of the exhaust? The thickness doesn't matter as I can get pretty much any size conduit clamp.
          >
          > stephen
          > -----------
          >
        • cjecje2
          The engine is bolted solid to the engine beds which of course are bonded to the hull. So as the engine doesn t move in relation to the hull - the idea of
          Message 4 of 13 , Apr 27, 2013
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            The engine is bolted solid to the engine beds which of course are bonded to the hull. So as the engine doesn't move in relation to the hull - the idea of supporting the long lever-arm of the exhaust pipe with something also solid to the boat seemed reasonable to me. I have and use Unistrut all the time to support refrigerant and other fluid piping so it wasn't a very inventive concept to me. <g>

            Before the recent re-piping the exhaust was a 24" length of heavy stainless steel pipe, subject to engine vibration and all other boat use/motion stresses, which was just sticking out from the engine two feet and completely unsupported. Supporting the new piping well just seemed prudent to me.

            stephen
            -----------





            On Apr 27, 2013, at 9:20 AM, niebur32 wrote:

            Hey Stephen, I don't quite parse your exhaust construction. But do I read it right that you fastened your exhaust to the boat with an unistrut (I had to google that)? Is that a good idea, shouldn't the exhaust move with the engine, rather than the boat?

            I rebuilt my exhaust last year. Come by once you are in your new place and have a look at the exhaust of the good ship Tavernier. The previous version lasted >10 years, at which point the black pipe was rusted out.h

            --Ernst

            --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@...> wrote:
            >
            >
            > My exhaust spud is under the stern and almost vertical. Sometimes the engine wouldn't start and I would find the sparkplug gaps shorted with water drops. Apparently when the boat would hobby-horse at the dock water would be forced in, the exhaust would fill, and eventually water would get into the engine. I felt that the hot-portion of the exhaust riser loop was too low.
            >
            > So I repiped it and put the riser loop as high up into the bridge deck as possible - about a foot or more higher than before.
            >
            > The previous exhaust pipe was un-supported after leaving the exhaust manifold and the 24" lever-arm it formed seemed like a very weak arrangement. In fact; the nipple into the exhaust manifold flange was already cracked about 50% when I removed it.
            >
            > So I also mounted a piece of 1 5/8" Unistrut under the bridge deck and used a conduit clamp to secure the top of the new exhaust riser to the unistrut.
            >
            > The top of the riser now consists of these items: a vertical pipe nipple up into a 90� ell - a 4" pipe nipple to form the horizontal - a 90� street ell with the male end facing down - and then a tee. The side connection of that tee is where the water is injected.
            >
            > I wrapped the hot portion of the exhaust pipe with standard 1 1/2" 'exhaust wrap' tape from the hot rod store. The exhaust was previously wrapped and I re-used that material but as the piping is now longer I bought another 50' of exhaust wrap to finish it. The pieces I cut were longer than actually required so much of the exhaust is now double-layer wrapped.
            >
            > Nonetheless; the bridge deck gets hot and the heads of the carriage bolts which secure the unistrut get too hot to touch.
            >
            > What else can I use to insulate the hot portion of the exhaust? The thickness doesn't matter as I can get pretty much any size conduit clamp.
            >
            > stephen
            > -----------
            >
          • cjecje2
            Well; there really is no direct heat contact/conducting path - at least not in terms of metal-to-metal contact. I m sure the exhaust wrap insulation does
            Message 5 of 13 , Apr 27, 2013
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              Well; there really is no "direct heat contact/conducting path" - at least not in terms of metal-to-metal contact. I'm sure the exhaust wrap insulation does 'something' in terms of separating the exhaust pipe from the unistut channel it's mounted to. And also from the unistrut clamp which secures it. But even without actual metal-to-metal contact - apparently a substantial of heat is being conducted through the exhaust wrap insulation.

              On Sunday I am (apparently <g>) going to motor continually for six to eight hours so I guess we'll see what happens.

              I was just 'in-my-head-designing' a water jacketed exhaust with which I could replace the entire hot section. I wonder if it could be 1 1/4" copper L tubing surrounded by 2" copper L tubing? That would be easier to fabricate. Otherwise I have to TIG together stainless and I don't have any of that. Then the water leaving the watercooler exhaust manifold on the end could be piped into the lowest portion of the outer shell, and then come out of the shell right before the water injection point. I am pretty sure that I could silver solder the inner joint before doing the outer joint - as I went along building it in sequence. I guess the inner tubing would want a few centering spaces here and there to maintain the 3/16" gap between the inner pipe and the outer shell tubing.

              Although . . . . better insulation of some kind sure seems easier. <g>

              stephen
              ----------



              On Apr 27, 2013, at 9:19 AM, Kbjmjrb@... wrote:

              The best way to separate exhaust heat from the rest of the hull is with some sort of air gap, or at least minimum direct contact between the pipe and the mounting hardware. Heat is transferred either by direct conduction or radiant heat, (IR). Is there some way you can pack the clamped areas with ss scrubbies or something to reduce the direct heat path from pipe to clamp? The heat tape is a help against radiant heat loss but it is still conducting too much heat. A narrower clamp would help. True, non conductive heat shields usually involve ceramics and have NASA part numbers.


              Bruce K
              Challenger # 74, "Ouroboros"
              Los Lunas, NM


              >
              >
              > My exhaust spud is under the stern and almost vertical. Sometimes the engine wouldn't start and I would find the sparkplug gaps shorted with water drops. Apparently when the boat would hobby-horse at the dock water would be forced in, the exhaust would fill, and eventually water would get into the engine. I felt that the hot-portion of the exhaust riser loop was too low.
              >
              > So I repiped it and put the riser loop as high up into the bridge deck as possible - about a foot or more higher than before.
              >
              > The previous exhaust pipe was un-supported after leaving the exhaust manifold and the 24" lever-arm it formed seemed like a very weak arrangement. In fact; the nipple into the exhaust manifold flange was already cracked about 50% when I removed it.
              >
              > So I also mounted a piece of 1 5/8" Unistrut under the bridge deck and used a conduit clamp to secure the top of the new exhaust riser to the unistrut.
              >
              > The top of the riser now consists of these items: a vertical pipe nipple up into a 90º ell - a 4" pipe nipple to form the horizontal - a 90º street ell with the male end facing down - and then a tee. The side connection of that tee is where the water is injected.
              >
              > I wrapped the hot portion of the exhaust pipe with standard 1 1/2" 'exhaust wrap' tape from the hot rod store. The exhaust was previously wrapped and I re-used that material but as the piping is now longer I bought another 50' of exhaust wrap to finish it. The pieces I cut were longer than actually required so much of the exhaust is now double-layer wrapped.
              >
              > Nonetheless; the bridge deck gets hot and the heads of the carriage bolts which secure the unistrut get too hot to touch.
              >
              > What else can I use to insulate the hot portion of the exhaust? The thickness doesn't matter as I can get pretty much any size conduit clamp.
              >
              > stephen
              > -----------
              >
            • cjecje2
              What appeals to me the most is this piping arrangement: The exhaust flange on the engine manifold A 2 long pipe nipple screwed into the flange A tee with the
              Message 6 of 13 , Apr 27, 2013
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                What appeals to me the most is this piping arrangement:

                The exhaust flange on the engine manifold
                A 2" long pipe nipple screwed into the flange
                A tee with the side screwed onto the above nipple
                The water injection point into the top of the tee
                The exhaust out the bottom of the tee.

                That would make everything, except the first nipple and half the tee, water-injection cooled. But then how to prevent cooling or seawater water from ever backing up into the engine? A check valve in the exhaust pipe seems unreliable to me. <g>

                Unless you can suggest a better insulating method or material - the only viable alternative I can think of is to water-jacket the exhaust pipe. My 1961 Triton exhaust was done in some way like that. And I think it was copper-in-copper. I know there was no riser or water lift muffler. The water leaving the exhaust manifold entered the exhaust pipe's water jacket and wasn't injected into the exhaust gas until just before the exhaust pipe connected to the exhaust spud / thru-hull at the stern of the boat. I didn't really pay much attention to it - because it never caused any problems. <g>

                stephen
                ----------
              • Jim Muri
                I m puzzled why you re re-inventing something that has long ago been solved. Which means that I must have missed something in this thread.  You keep sea water
                Message 7 of 13 , Apr 27, 2013
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                  I'm puzzled why you're re-inventing something that has long ago been solved. Which means that I must have missed something in this thread. 

                  You keep sea water from backing up into the engine by putting a large loop in the exhaust system.  You can also put a rubber or spring-loaded flapper at the end of the exhaust where it leaves the boat, so that the exhaust is closed unless the engine is running.    
                   

                  From: cjecje2 <cjecje2@...>
                  To: columbiasailingyachts@yahoogroups.com
                  Sent: Saturday, April 27, 2013 7:44 AM
                  Subject: Re: CYOA - Re: exhaust design ??

                   

                  What appeals to me the most is this piping arrangement:

                  The exhaust flange on the engine manifold
                  A 2" long pipe nipple screwed into the flange
                  A tee with the side screwed onto the above nipple
                  The water injection point into the top of the tee
                  The exhaust out the bottom of the tee.

                  That would make everything, except the first nipple and half the tee, water-injection cooled. But then how to prevent cooling or seawater water from ever backing up into the engine? A check valve in the exhaust pipe seems unreliable to me. <g>

                  Unless you can suggest a better insulating method or material - the only viable alternative I can think of is to water-jacket the exhaust pipe. My 1961 Triton exhaust was done in some way like that. And I think it was copper-in-copper. I know there was no riser or water lift muffler. The water leaving the exhaust manifold entered the exhaust pipe's water jacket and wasn't injected into the exhaust gas until just before the exhaust pipe connected to the exhaust spud / thru-hull at the stern of the boat. I didn't really pay much attention to it - because it never caused any problems. <g>

                  stephen
                  ----------


                • cjecje2
                  Well, as it always seems with me; there is more to the story. But I had already wrote a whole page explaining just the bit that you know so far. The
                  Message 8 of 13 , Apr 27, 2013
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                    Well, as it always seems with me; there is more to the story. But I had already wrote a whole page explaining just the bit that you know so far. <g>

                    The entire exhaust was done wrong: first there was the unsupported riser (actually sticking out at a 45º angle) which was too short / not far above the water line.

                    On the cool side of that riser the exhaust went into the water lift muffler.

                    From the water lift muffler the steam hose bends a short 90º turn and then runs flat under the cockpit and pretty much straight to the exhaust spud under the counter. And as the exit for the exhaust faces almost straight down - an exterior mounted exhaust flap is not do-able in any effective way.

                    The previous owners were accountant / money manager types. The boatyard mechanics were all either stupid or malicious and maybe both as they charged the owners really substantial sums to do dogshit grade work.

                    About 12 years ago this boat had a new exhaust system 'upgrade' - all welded stainless steel riser, all new hoses, pipes, water-lift muffler, etc.

                    And this boat has also had three new engine in the ten years following that particular upgrade. Why? Because the exhaust system is AFU. But the owners then were not engineers or mechanics so the yard monkeys just kept treating the symptom and never admitting to have effed up the whole thing by their shit-grade work in the first place.

                    Now of course that all benefited me because they almost gave me this incredibly well equipped and outfitted boat just to be rid of the "un-solveable" problems it had. <g>

                    Now I can just leave my new longer higher exhaust riser in place and I am almost positive that water infiltration will not be a problem for the engine. But I was also curious about how to reduce the heat in the engine compartment and bridge deck. Sure; I can just shove the bilge blower hose up under the bridge deck and run the blower whenever I run the engine. I tried insulating the hot section but more seems to be required.

                    Which is what made me both ask and muse about just how that might be done. <g>

                    stephen
                    ------------




                    On Apr 27, 2013, at 10:54 AM, Jim Muri wrote:


                    I'm puzzled why you're re-inventing something that has long ago been solved. Which means that I must have missed something in this thread.

                    You keep sea water from backing up into the engine by putting a large loop in the exhaust system. You can also put a rubber or spring-loaded flapper at the end of the exhaust where it leaves the boat, so that the exhaust is closed unless the engine is running.

                    James R. Muri

                    Novelist, Sailor
                    BUY: My e-Novels at http://blizzardguy.com/venture/
                    SITE: http://blizzardguy.com
                    BLOG: http://theostrichkiller.blogspot.com
                    From: cjecje2 <cjecje2@...>
                    To: columbiasailingyachts@yahoogroups.com
                    Sent: Saturday, April 27, 2013 7:44 AM
                    Subject: Re: CYOA - Re: exhaust design ??



                    What appeals to me the most is this piping arrangement:

                    The exhaust flange on the engine manifold
                    A 2" long pipe nipple screwed into the flange
                    A tee with the side screwed onto the above nipple
                    The water injection point into the top of the tee
                    The exhaust out the bottom of the tee.

                    That would make everything, except the first nipple and half the tee, water-injection cooled. But then how to prevent cooling or seawater water from ever backing up into the engine? A check valve in the exhaust pipe seems unreliable to me. <g>

                    Unless you can suggest a better insulating method or material - the only viable alternative I can think of is to water-jacket the exhaust pipe. My 1961 Triton exhaust was done in some way like that. And I think it was copper-in-copper. I know there was no riser or water lift muffler. The water leaving the exhaust manifold entered the exhaust pipe's water jacket and wasn't injected into the exhaust gas until just before the exhaust pipe connected to the exhaust spud / thru-hull at the stern of the boat. I didn't really pay much attention to it - because it never caused any problems. <g>

                    stephen
                    ----------
                  • niebur32
                    Engine bolted solid to the hull? No motor mounts? Hm, that is very different from what my A4 has. And yes, I do support the exhaust pipes, but to the motor,
                    Message 9 of 13 , Apr 27, 2013
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                      Engine bolted solid to the hull? No motor mounts? Hm, that is very different from what my A4 has.

                      And yes, I do support the exhaust pipes, but to the motor, not the hull.

                      --Ernst


                      --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@...> wrote:
                      >
                      >
                      > The engine is bolted solid to the engine beds which of course are bonded to the hull. So as the engine doesn't move in relation to the hull - the idea of supporting the long lever-arm of the exhaust pipe with something also solid to the boat seemed reasonable to me. I have and use Unistrut all the time to support refrigerant and other fluid piping so it wasn't a very inventive concept to me. <g>
                      >
                      > Before the recent re-piping the exhaust was a 24" length of heavy stainless steel pipe, subject to engine vibration and all other boat use/motion stresses, which was just sticking out from the engine two feet and completely unsupported. Supporting the new piping well just seemed prudent to me.
                      >
                      > stephen
                      > -----------
                      >
                      >
                      >
                      >
                      >
                      > On Apr 27, 2013, at 9:20 AM, niebur32 wrote:
                      >
                      > Hey Stephen, I don't quite parse your exhaust construction. But do I read it right that you fastened your exhaust to the boat with an unistrut (I had to google that)? Is that a good idea, shouldn't the exhaust move with the engine, rather than the boat?
                      >
                      > I rebuilt my exhaust last year. Come by once you are in your new place and have a look at the exhaust of the good ship Tavernier. The previous version lasted >10 years, at which point the black pipe was rusted out.h
                      >
                      > --Ernst
                      >
                      > --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@> wrote:
                      > >
                      > >
                      > > My exhaust spud is under the stern and almost vertical. Sometimes the engine wouldn't start and I would find the sparkplug gaps shorted with water drops. Apparently when the boat would hobby-horse at the dock water would be forced in, the exhaust would fill, and eventually water would get into the engine. I felt that the hot-portion of the exhaust riser loop was too low.
                      > >
                      > > So I repiped it and put the riser loop as high up into the bridge deck as possible - about a foot or more higher than before.
                      > >
                      > > The previous exhaust pipe was un-supported after leaving the exhaust manifold and the 24" lever-arm it formed seemed like a very weak arrangement. In fact; the nipple into the exhaust manifold flange was already cracked about 50% when I removed it.
                      > >
                      > > So I also mounted a piece of 1 5/8" Unistrut under the bridge deck and used a conduit clamp to secure the top of the new exhaust riser to the unistrut.
                      > >
                      > > The top of the riser now consists of these items: a vertical pipe nipple up into a 90� ell - a 4" pipe nipple to form the horizontal - a 90� street ell with the male end facing down - and then a tee. The side connection of that tee is where the water is injected.
                      > >
                      > > I wrapped the hot portion of the exhaust pipe with standard 1 1/2" 'exhaust wrap' tape from the hot rod store. The exhaust was previously wrapped and I re-used that material but as the piping is now longer I bought another 50' of exhaust wrap to finish it. The pieces I cut were longer than actually required so much of the exhaust is now double-layer wrapped.
                      > >
                      > > Nonetheless; the bridge deck gets hot and the heads of the carriage bolts which secure the unistrut get too hot to touch.
                      > >
                      > > What else can I use to insulate the hot portion of the exhaust? The thickness doesn't matter as I can get pretty much any size conduit clamp.
                      > >
                      > > stephen
                      > > -----------
                      > >
                      >
                    • harryjak
                      The A4 I took out of Sheer was hard bolted to the mounts. It had an un lagged exhaust to standpipe exhaust. I plan on putting in another stand pipe exhaust,
                      Message 10 of 13 , Apr 28, 2013
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                        The A4 I took out of "Sheer" was hard bolted to the mounts. It had an un lagged
                        exhaust to standpipe exhaust. I plan on putting in another stand pipe exhaust, the
                        engine is so far into the bilge that a water lift won't work. When I get home I
                        will copy a picture of the standpipe exhaust out of David Gerr's book and post it.
                        I was having some real problems on figuring out what to do before I saw that.

                        David Gerr is adamant that if your exhaust is bolted down you need a flexible
                        bellows coupling to the engine. I am not sure if that applies if the engine is
                        hard mounted.

                        HJ


                        > My exhaust spud is under the stern and almost vertical. Sometimes the engine
                        > wouldn't start and I would find the sparkplug gaps shorted with water drops.
                        > Apparently when the boat would hobby-horse at the dock water would be forced in,
                        > the exhaust would fill, and eventually water would get into the engine. I felt
                        > that the hot-portion of the exhaust riser loop was too low.
                        >
                        > So I repiped it and put the riser loop as high up into the bridge deck as possible
                        > - about a foot or more higher than before.
                        >
                        > The previous exhaust pipe was un-supported after leaving the exhaust manifold and
                        > the 24" lever-arm it formed seemed like a very weak arrangement. In fact; the
                        > nipple into the exhaust manifold flange was already cracked about 50% when I
                        > removed it.
                        >
                        > So I also mounted a piece of 1 5/8" Unistrut under the bridge deck and used a
                        > conduit clamp to secure the top of the new exhaust riser to the unistrut.
                        >
                        > The top of the riser now consists of these items: a vertical pipe nipple up into a
                        > 90º ell - a 4" pipe nipple to form the horizontal - a 90º street ell with the male
                        > end facing down - and then a tee. The side connection of that tee is where the
                        > water is injected.
                        >
                        > I wrapped the hot portion of the exhaust pipe with standard 1 1/2" 'exhaust wrap'
                        > tape from the hot rod store. The exhaust was previously wrapped and I re-used that
                        > material but as the piping is now longer I bought another 50' of exhaust wrap to
                        > finish it. The pieces I cut were longer than actually required so much of the
                        > exhaust is now double-layer wrapped.
                        >
                        > Nonetheless; the bridge deck gets hot and the heads of the carriage bolts which
                        > secure the unistrut get too hot to touch.
                        >
                        > What else can I use to insulate the hot portion of the exhaust? The thickness
                        > doesn't matter as I can get pretty much any size conduit clamp.
                        >
                        > stephen
                        > -----------
                        >
                        > ------------------------------------
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                      • cjecje2
                        If you willing to undergo the bodily origami required I will show some of them to when you get back to this part of the planet. What kind of mounts does Your
                        Message 11 of 13 , Apr 29, 2013
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                          If you willing to undergo the bodily origami required I will show some of them to when you get back to this part of the planet. What kind of mounts does Your A-4 have?

                          As people were talking about rubber mounts - I realized that I have never had a boat with a gasoline engine which didn't have the engine bolted directly to the beds. A-2's, A-4's, a Kermath, and a Gray - all bolted solid. On the other hand; all the diesels have been rubber mounted.

                          I never gave it much thought before and if properly aligned the gas engines are pretty smooth running.

                          stephen
                          -----------



                          On Apr 27, 2013, at 8:49 PM, niebur32 wrote:

                          Engine bolted solid to the hull? No motor mounts? Hm, that is very different from what my A4 has.

                          And yes, I do support the exhaust pipes, but to the motor, not the hull.

                          --Ernst
                          -------------


                          --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@...> wrote:
                          >
                          >
                          > The engine is bolted solid to the engine beds which of course are bonded to the hull. So as the engine doesn't move in relation to the hull - the idea of supporting the long lever-arm of the exhaust pipe with something also solid to the boat seemed reasonable to me. I have and use Unistrut all the time to support refrigerant and other fluid piping so it wasn't a very inventive concept to me. <g>
                          >
                          > Before the recent re-piping the exhaust was a 24" length of heavy stainless steel pipe, subject to engine vibration and all other boat use/motion stresses, which was just sticking out from the engine two feet and completely unsupported. Supporting the new piping well just seemed prudent to me.
                          >
                          > stephen
                          > -----------
                        • niebur32
                          yes, rubber mounts, that s what I have. Looking forward to seeing your installation.
                          Message 12 of 13 , Apr 30, 2013
                          • 0 Attachment
                            yes, rubber mounts, that's what I have. Looking forward to seeing your installation.



                            --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@...> wrote:
                            >
                            >
                            > If you willing to undergo the bodily origami required I will show some of them to when you get back to this part of the planet. What kind of mounts does Your A-4 have?
                            >
                            > As people were talking about rubber mounts - I realized that I have never had a boat with a gasoline engine which didn't have the engine bolted directly to the beds. A-2's, A-4's, a Kermath, and a Gray - all bolted solid. On the other hand; all the diesels have been rubber mounted.
                            >
                            > I never gave it much thought before and if properly aligned the gas engines are pretty smooth running.
                            >
                            > stephen
                            > -----------
                            >
                            >
                            >
                            > On Apr 27, 2013, at 8:49 PM, niebur32 wrote:
                            >
                            > Engine bolted solid to the hull? No motor mounts? Hm, that is very different from what my A4 has.
                            >
                            > And yes, I do support the exhaust pipes, but to the motor, not the hull.
                            >
                            > --Ernst
                            > -------------
                            >
                            >
                            > --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@> wrote:
                            > >
                            > >
                            > > The engine is bolted solid to the engine beds which of course are bonded to the hull. So as the engine doesn't move in relation to the hull - the idea of supporting the long lever-arm of the exhaust pipe with something also solid to the boat seemed reasonable to me. I have and use Unistrut all the time to support refrigerant and other fluid piping so it wasn't a very inventive concept to me. <g>
                            > >
                            > > Before the recent re-piping the exhaust was a 24" length of heavy stainless steel pipe, subject to engine vibration and all other boat use/motion stresses, which was just sticking out from the engine two feet and completely unsupported. Supporting the new piping well just seemed prudent to me.
                            > >
                            > > stephen
                            > > -----------
                            >
                          • cjecje2
                            OK. And the cockpit lockers you have to origami yourself into are now polished and sparkling clean too - my clothing has done a remarkably job of moping them
                            Message 13 of 13 , Apr 30, 2013
                            • 0 Attachment
                              OK. And the cockpit lockers you have to origami yourself into are now polished and sparkling clean too - my clothing has done a remarkably job of moping them spotless.

                              stephen
                              -----------



                              On Apr 30, 2013, at 6:40 PM, niebur32 wrote:

                              yes, rubber mounts, that's what I have. Looking forward to seeing your installation.

                              --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@...> wrote:
                              >
                              >
                              > If you willing to undergo the bodily origami required I will show some of them to when you get back to this part of the planet. What kind of mounts does Your A-4 have?
                              >
                              > As people were talking about rubber mounts - I realized that I have never had a boat with a gasoline engine which didn't have the engine bolted directly to the beds. A-2's, A-4's, a Kermath, and a Gray - all bolted solid. On the other hand; all the diesels have been rubber mounted.
                              >
                              > I never gave it much thought before and if properly aligned the gas engines are pretty smooth running.
                              >
                              > stephen
                              > -----------
                              >
                              >
                              >
                              > On Apr 27, 2013, at 8:49 PM, niebur32 wrote:
                              >
                              > Engine bolted solid to the hull? No motor mounts? Hm, that is very different from what my A4 has.
                              >
                              > And yes, I do support the exhaust pipes, but to the motor, not the hull.
                              >
                              > --Ernst
                              > -------------
                              >
                              >
                              > --- In columbiasailingyachts@yahoogroups.com, cjecje2 <cjecje2@> wrote:
                              > >
                              > >
                              > > The engine is bolted solid to the engine beds which of course are bonded to the hull. So as the engine doesn't move in relation to the hull - the idea of supporting the long lever-arm of the exhaust pipe with something also solid to the boat seemed reasonable to me. I have and use Unistrut all the time to support refrigerant and other fluid piping so it wasn't a very inventive concept to me. <g>
                              > >
                              > > Before the recent re-piping the exhaust was a 24" length of heavy stainless steel pipe, subject to engine vibration and all other boat use/motion stresses, which was just sticking out from the engine two feet and completely unsupported. Supporting the new piping well just seemed prudent to me.
                              > >
                              > > stephen
                              > > -----------
                              >
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