Volvo 940 2.5 tdi diesel 6 cly 140 hp - me gonna maranise it!

Discussion in 'DIY Marinizing' started by corglass, Jun 6, 2010.

  1. corglass
    Joined: Jun 2010
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    Location: Ireland

    corglass Junior Member

    Hi there,

    I'm currently building a 19 Glastron speedboat that will be powered by a volvo 940 2.4 6 cly turbo diesel engine (140hp) via an Alpha one (Gen II) stern drive.

    I'm completely new to this so I'd love some help.

    I've already purchased the engine and would love some help on ideas to maranise it. Money is tight so any cost saving ideas would be appreciated! :D
    At the moment, the plan is use the water feed from the stern drive directly into the engine, and then let that exit through a homemade wet exhaust. I'm hoping the start thermostat will sort all.

    I head somewhere that you should cool the sump of the engine? Is this true?

    Thats prestty much it, I'd love to know if I'm overlooking anything?


    Irish Conor
     
  2. corglass
    Joined: Jun 2010
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    corglass Junior Member

    Cor,

    Not to put a damper on your enthusiasm, but marinizing an engine is a major undertaking that normally costs at least as much as buying a Marine engine to start with.

    But to get you started you are looking at doing at least the following:

    Adding a water cooled exhaust manifolds
    Addine a marine water pump
    Adjusting the carburetor tilt shim or angle plate (perhaps)
    Adding a carburetor flame arrestor or "backfire" trap
    Changing to brass freeze plugs (for saltwater use)
    Moving the engine mounts
    Increasing the alternator size (depending on current draw, and battery size)

    And the following need to be checked for Marine applications
    oil filter relocation kit
    oil coolers
    water cooled exhaust risers or elbows
    various cover plates
    various hose and plumbing assemblies
    various brackets and pulleys
    starter shaft extensions
    lifting rings

    Also you NEED to confirm that every single part on the engine, every pump, every electrical connection, every power take off, are sealed or rated to use in a gas vapor rich environment.



    I know it is tempting to try and convert an old car engine to marine use, but in my experience unless you are doing it for the fun of the project it probably isn't worth it.
     
  3. corglass
    Joined: Jun 2010
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    Location: Ireland

    corglass Junior Member

    i pasted the above reply from my email cos I couldn't see it:
    ---------------------------------------

    Hi Stumble,

    Thanks for your comments. I'll try to answer them 1 by 1.


    Adding a water cooled exhaust manifolds
    I'll do this alright

    Addine a marine water pump
    I had planned on relying on the pump from the alpha one stern dirve?

    Adjusting the carburetor tilt shim or angle plate (perhaps)
    The engine is diesel, so no carbs. Will i need to modify the injector pump?

    Adding a carburetor flame arrestor or "backfire" trap
    No need, the boats diesel?

    Changing to brass freeze plugs (for saltwater use)
    It's only gonna be in freshwater so no need.

    Moving the engine mounts
    I've already done this, but good spot.

    Increasing the alternator size (depending on current draw, and battery size)
    I dont think I'll have much current draw so will leave as is.


    And the following need to be checked for Marine applications
    oil filter relocation kit
    I might get away with leaving it as is, I seem to have plenty of room.

    oil coolers
    The car came with an amulinum oil cooler so will use that.

    water cooled exhaust risers or elbows
    Good call, I plan on building my own. Any idea where I could source drawings?

    various cover plates
    Agreed, again I'll build these myself.

    various hose and plumbing assemblies
    I dont thing I'll need to many, just water cooling from the stern to then block?


    various brackets and pulleys
    ageed,

    starter shaft extensions
    why do i need this?


    lifting rings
    Are these ESSENTIAL?

    Also you NEED to confirm that every single part on the engine, every pump, every electrical connection, every power take off, are sealed or rated to use in a gas vapor rich environment.
    No need, as the engine is diesel?


    I really appreciate your help!
     
  4. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Corglass I wrote down my comments in the same email listing:

    What you also need and has not been listed is the following.

    -An engine coupler instead of the clutch group that was mounted inside the flywheel.

    -A return fuel line to the tank plus the filter used in the car.

    -And if this really is a TDI engine, you need the MMU (motor management unit) and a wiring diagram so you can adapt it for its future life.

    About the plumbing:
    You now have the chance to do things right. Install a heat exchanger and make a closed cooling system. Then you can run the engine at the proper operating temperature, have no frost problems in winter and your thermostat will not fail because something gets lodged in the gap.
    Use the impeller pump to feed water through the exchanger and dump that in the manifold jacket. Let the block mounted pump circulate cooling liquid through the block.
    You avoid corrosion and save fuel!
     
  5. corglass
    Joined: Jun 2010
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    Location: Ireland

    corglass Junior Member


    Thanks CKD for all the advice.
    I think I plan on mounting a short FIXED shaft on the insdie of the alpha one that will cradle a carrier bearing. One end will be the female side on an alpha one to feed the stern drive. The shaft will be rigid, and aligned as best possible. The sftern drive should be able to retract in the up position.


    On the other end of this 'short shaft' I plan to put a univeral joint, followed by a short shaft, and then another univeral join on th engine at the flywheel.


    How does all this sound? Do you want me to do a diagram? thought so, [​IMG]


    Thanks again,

    Conor
     
  6. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    If money is tight, custom marinizing an engine is not an option for you. This is something you should've asked before buying. It will be cheaper to sell it an buy a used already marinized engine.
     
  7. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Well, it doesn't sound too bad, but the diagram looks like **** of course, I guess you know that.
    The Alpha One drive shaft, when properly lined out, exits the gimbal bearing almost horizontally, so anything you want to add to that should better stay in line with that. There also is some axial displacement between the drive fully down and up, so something must be able to slide.

    What reason do you have for adding so much iron when welding the proper bracket and replacing the clutch plate with an engine coupler is an inexpensive solution?
    And doesn't the extra length put your engine so much forward that you cannot close the hood anymore?
     

  8. fcfc
    Joined: Feb 2005
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    fcfc Senior Member

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