Air cooled sailboat motor

Discussion in 'DIY Marinizing' started by 8ball, Feb 7, 2016.

  1. 8ball
    Joined: Jan 2013
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    Location: Maine

    8ball Junior Member

    I'm starting a project to install a Lifan air cooled 15 hp gas motor in my 23 ft sailboat. I've found an adapter to mate a 2 to 1 ZF marine transmission to a small industrial engine. I was considering an outboard but for various reasons I wanted to stay with an inboard. New diesel engines cost around eight thousand dollars with the transmission, and used run around half of that if in good shape. I paid $369.00 for the Lifan new, the adapter cost $250.00 with shipping and I found a good used transmission for $200.00 dollars. So it's costing well less than a thousand dollars with the extras needed for the project. A new 9.9 hp outboard costs either side of two thousand depending on make and model. While there are certainly some drawbacks to my setup there are a number of advantages primarily around costs and convenience. Maintenance is simple as everything is easily accessed and no more difficult than a lawnmower. I can replace the engine with a large variety of engines that share a standard output bolt pattern, as well as a number of transmissions such as PRM, Technodrive and Hurth/ZF, that all use the same mounting bolt pattern and input/output shafts. I was given the sailboat which is a Westerly Pageant that originally had a Vire 7.5 hp two stroke gas motor in it. The biggest engineering difficulty is the exhaust. I intend to use a dry exhaust and am still contemplating it's arrangement. As I move along I'll try and update with photos. I would enjoy hearing any comments or suggestions, especially anyone with experience in this area. I have a 28 ft open dory with a 9 hp Lister air cooled diesel that has worked out quite well. If I can solve the exhaust issue satisfactorily I believe this project will be a success as well.
     
  2. Yobarnacle
    Joined: Nov 2011
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    Location: Mexico, Florida

    Yobarnacle Senior Member

    I'm intending a dry exhaust for my 10hp diesel.
    A crossover pipe port gunnel to starboard gunnel with ball valves where engine exhaust tees in the middle.
    On each narrow side deck, a pop-out inspection plate over the elbow terminus of the crossover pipe.
    A removable vertical exhaust pipe/w/muffler stack can be plugged into either side, which ever is in the lee, so the exhaust is carried away from the cockpit.
    A pair of welders gloves enables moving a hot pipe stack.
    The inspection port covers keep out the water when the exhaust pipe stack isn't in the hole.
    What you think?
     
  3. 8ball
    Joined: Jan 2013
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    Location: Maine

    8ball Junior Member

    Sounds like a slick setup, I like the side to side part. I once had a Norwegian boat with a North Sea exhaust, wet though, that exited on both sides. My boat has quarter berths on either side of the engine space so I was hoping to go basically straight up. I'm toying with running lagged stainless flex hose into a standard marine stove chimney. It's all stainless and I can get three inch insulated pipe. Outside use the chimney thru deck and what here in Maine we call a "Charlie Noble" chimney cap. I'm going to try the components before the engine goes in to measure heat and noise.
     
  4. gonzo
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    gonzo Senior Member

    Noise is going to be difficult to avoid. A dry stack by the cockpit, is like having a lawnmower running on your picnic table. The chimney cap will reflect the noise down too. There is a water intake from the previous engine. You could use a pump to run cooling water on the exhaust, and re-use the previous setup.
     
  5. Yobarnacle
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    Location: Mexico, Florida

    Yobarnacle Senior Member

  6. gonzo
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    gonzo Senior Member

    The problem with the setup is the length necessary to muffle the noise. Even a motorcycle (with a quiet system) has about 5 feet of pipe/muffler. In a car, the length is even longer. I also think is it very difficult to work around a hot muffler on a small sailboat. Larger boats can afford the space losses for insulation and outer stack. However, that is largely a personal choice. High temperature in the engine compartment is another hard issue to fix without forced ventilation. Mufflers work when they are properly designed. Would you like to motor for long next to a lawnmower? Some people actually enjoy the noise (read motorcycles with straight pipes ;))
     
  7. Yobarnacle
    Joined: Nov 2011
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    Location: Mexico, Florida

    Yobarnacle Senior Member

    All true.

    for my boat, a few hours motoring would be the longest run.
    Mostly, just 20 minutes through a crowded anchorage or winding into a marina slip.

    I might even set up my mast as an exhaust stack.
    I don't plan to carry sails on the mast itself.
    Just genoa on the headstay, and a lateen yard on a jackstay.

    masthead 18 ft above deck, 4 inches diameter aluminum, aft mast rig.
     
  8. gonzo
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    gonzo Senior Member

    On larger sailing ships, masts have been used as stacks. If lines and sails don't touch it, you probably only need insulation for as high as a person can touch.
     
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  9. 8ball
    Joined: Jan 2013
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    Location: Maine

    8ball Junior Member

    Gonzo, those are some excellent points. I'm sure you're correct that there's going to be a noise issue pretty much no matter what I come up with. My Lister in the other boat has a kind of pleasant sound but this Lifan, as you said sounds like your average lawnmower. I've done some work trying to silence a portable generator and had some success with an industrial hospital muffler but it's mild steel and quite large. I used to have a boat with a Detroit 4-71 that I put a Cowl muffler on and it work very well, but again pretty big. I do have room to go aft and come up behind the cockpit where I could place a deflector between the outlet and the cockpit which would put the exhaust and some of the noise behind the boat. There is a company near me that fabricates exhaust blankets and I could insulate the entire length ( about six feet ).
     
  10. gonzo
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    gonzo Senior Member

    It may be possible to run the exhaust under water. That helps keep some of the noise down. However, there needs to be some way to let air go in after the engine stops. Otherwise, when the exhaust gasses cool down and contract it may such too much water in. A small pipe going up may be enough. Some air cooled outboards exhaust under the water. Insulation of dry exhaust is always hard. You could try running the engine before installation and see what the temperature is. Remember that the engine compartment in a sailboat is pretty much an enclosed space. Ideally the air temperature should not be more than 150F.
     
  11. JSL
    Joined: Nov 2012
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    JSL Senior Member

    I assume you have allowed for the CO matter like backwash, spilling down into the cabin (I believe CO is heavier than air). Fumes often don't go where you want them
     
  12. Yobarnacle
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    Yobarnacle Senior Member

    thanks Gonzo
     
  13. 8ball
    Joined: Jan 2013
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    8ball Junior Member

    I have the ventilation set up so that air is drawn from vents on both sides of the cabin about even with the mast. The air is piped down below the cabin sole and comes up directly in front of and below the engine. As the engine gets it's cooling air through the front, fresh air should be drawn in for cooling. There are four vents at the stern, three with a high exit to vent hot air and one piped to the bilge with a blower for ventilation before starting. I've run the blower while using a bee smoker to put smoke into the forward vents and then followed the smoke path through the boat and it vents the boat completely including the bilge. I also tried the same thing with a small computer fan placed where the engine will be and that worked well also. I'm researching underwater exhaust, interesting idea, thanks Gonzo.
     
  14. Yobarnacle
    Joined: Nov 2011
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    Location: Mexico, Florida

    Yobarnacle Senior Member

    Smokey exhaust frequently means air starved,



    "White smoke is generally most noticeable at engine start-up, particularly during cold conditions. As the combustion and cylinder temperatures increase during the first few minutes of engine operation the white smoke should start to disappear which indicates the engine is sound. However, if the white smoke takes longer than 3 to 5 minutes to disappear a problem exist. The problems white smoke may indicate are as follows:

    Low cylinder compression from worn rings
    Scored piston or liner
    Valve seating problems
    Water leaking into the combustion chamber
    Faulty injectors
    Use of a low cetane diesel fuel.

    Black or gray smoke generally is caused by the same conditions—the difference between the colors being one of opacity or denseness of smoke. Black or gray smoke should be checked with the engine at operating temperature of 160°F. Abnormal amounts of exhaust smoke emission is an indication that the engine is not operating correctly, resulting in a lack of power, as well as decreased fuel economy. Excessive black or gray exhaust smoke is caused by the following:

    Improper grade of diesel fuel
    Air starvation
    High exhaust back pressure
    Incorrect fuel injection timing
    Faulty nozzles or injectors
    Faulty automatic timing advance unit
    Faulty injection pump Incorrect valve adjustment clearances

    Blue smoke is attributed to oil entering the combustion chamber and being burned or blown through the cylinder and burned in the exhaust manifold or turbocharger. Remember always check the simplest things first, such as too much oil in the crankcase or a plugged crankcase ventilation breather. The more serious problems that can cause blue smoke are as follows:

    Worn valve guides
    Worn piston rings
    Worn cylinder walls
    Scored pistons or cylinder walls
    Broken rings
    Turbocharger seal leakage
    Glazed cylinder liner walls due to use of the wrong type of oil"

    http://www.waybuilder.net/sweethaven/MechTech/Automotive01/default.asp?unNum=4&lesNum=10&modNum=1
     
    Last edited: Feb 9, 2016

  15. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    Find a nice motorcycle STOCK muffler from a BMW or other bike built where there are noise laws that are respected.

    10HP is not a big deal to silence.
     
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