Truck diesels

Discussion in 'DIY Marinizing' started by parkland, Nov 7, 2012.

  1. slow fred
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    slow fred Junior Member

    Over the last 25 or so years I have owned several 466s, in medium duty work trucks. They will last if you spin in a set of bearings every 150k and keep very close watch on the coolant condition. If you don't they are bad about leaking o-rings on the liners. When you compare the Cummins 5.9 and the 466s, you are not comparing apples to apples.
     
  2. parkland
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    parkland Senior Member



    i know a few people who run them even still, and worked for a guy that had 3, and I have yet to hear of any of them ever trashing bearings withing a couple hundred thousand miles. The 1 of them has been rebuilt 3 times now, every 400,000 miles or so and it's getting 400.000 miles on pure stop and go traffic, in my opinion, 400,000 is a lot of stop and go miles.

    The coolant; yes. Any wet sleeve engine, the coolant is important. Important in any engine, but a wet sleeve will fail sooner if something is wrong.
     
  3. parkland
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    parkland Senior Member


    Yeah, I saw that...
    Weird... they always say "Genuine cummins engine", or "genuine cummins generator", but the cost is usually around half of what they normally go for...
    Clones I assume?
    I honestly don't know.
    I wonder how come we don't see more of those clones, I bet if a company imported say 10 units, they could maybe get seized?
    I know once in a while, a clothing store gets the merchandise taken away by the cops, cause it's "fake" brand name stuff that was imported.

    http://www.alibaba.com/product-gs/689538353/big_power_cummins_6CTA8_3_M300.html?s=p
     
  4. woodboatwayne
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    woodboatwayne Junior Member

    In my paygrade you run what is is serviceable and affordable. That includes marinization if necessary. Had a friend that swore by his Mac diesels which he converted. As noted earlier in this thread most yacht diesels break down due to neglect
    wrather than use. I find it interesting that Cat rates engine longevity by fuel consumed, making a good point regarding pushing the power to maximum. Before electronic controls 80 or 90% of all failures were supposedly fuel related. Guess what, after your
    computer, sensor, electronic failures you still have at least the same or more likely more fuel related problems. Go figure.
    Woodboatwayne
     
  5. parkland
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    parkland Senior Member


    Yeah I remember hearing that 95% of diesel engine failures could be blamed on fuel issues, or coolant issues.
    Common rail diesels are terrible with water, and the injectors can get stuck open from debris off the high pressure fuel pump, wich gets damaged from water, destroying the engine from a melt down.

    I don't understand why they can't test fuel quality similar to how they test oil quality; with a capacitance sensor.
     
  6. woodboatwayne
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    woodboatwayne Junior Member

    I don't know about the capacitance test. How does it work?
     
  7. parkland
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    parkland Senior Member


    Honestly I don't know the technical details.

    Newer cars that tell you when to change the oil, they determine that from a capacitance sensor. Apparently the capacitance value of the oil is a close relationship to the oil quality.

    Any way you slice it, new diesels deserve a better fuel quality sensor of SOME kind.
     
  8. DCockey
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    DCockey Senior Member

    A variety of methods are used to determine when the "change oil" indicator turns on. They include sensors which measure capacitance, conductivity and other properties. Another approach is to record the engine operating conditions and calculate remaining oil life based on those conditions. Some vehicles use combinations of direct sensing and calculations.
     
  9. woodboatwayne
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    woodboatwayne Junior Member

    Thanks,I agree you would think they could
     
  10. parkland
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    parkland Senior Member

    Yes you're right.
    From what I've read and been told, some higher end cars employ more advanced methods to determine oil quality, like number of cold starts. time from start to operating temperature, etc.
    I mentioned the capacitance sensor, because it was the only sensor I could picture being useful to monitor an oil substance like fuel, "on the fly".

    A huge asset to modern diesels, IMHO, would be to monitor the pressure drop across the filter / water block membrane.
    Anyone that knows about water blocking membrane filters, knows that the membrane "repells?" water... in the sense that when water is in the fuel, and hits the membrane, it is supposed to shed off, and end up in the bottom of the fuel bowl.
    But, membranes are not perfect. With enough pressure, the water can be forced through the membrane, and into the fuel system.

    The water in fuel sensor on most diesels, just tells if the water has accumulated in the bowl. If the membrane becomes overcome with gunk, water, or other debris, it takes multiple PSI of pressure loss for the ECM to think that anything is wrong.
    Why don't they have a pressure drop sensor? I think it would be hard to implement. Fuel flow varies, temperatures change viscosity, etc. So the pressure drop would always be changing. It would take a pretty powerful little computer to figure it out in real time.
     
  11. dskira

    dskira Previous Member

    Fuel quality should be the least of the problem for a real vessel engine. Going around the world, you can't get the superb fuel quality the engine manufacturer want. These new diesel are just quality highway engine, flimsy and unreliable. Asking for the perfect fuel, should be not in the agenda for real cruiser.
    As for computerize engines, live them for the delivery trucks, they have no place on a real cruiser.
    High speed diesel should also not in a boat. They have the same lifespan before overall than a gas engine.
    If someone who own a car doesn't know when to change the oil, it's bad. Just look at the sticker.
     
  12. parkland
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    parkland Senior Member


    Changing oil every xxxx miles works, but there might be times where it could go longer, and there might be times where it could use a change sooner.

    IMHO, oil quality sensors are a good technology, and I hope to see them evolve further.
     
  13. parkland
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    parkland Senior Member

    What is a "real vessel", or "real cruiser"?
    I agree, with a boat, that reliability is paramount, but electronics are becoming more popular by the day.
    Emission laws will slowly start effecting boats more and more, I think.
    I'm not an expert on the subject, but I think most of the new diesel will be common rail very soon.

    As much as old mechanical diesel engines are reliable and tough, I do think there is an end in sight.
     
  14. woodboatwayne
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    woodboatwayne Junior Member

    I don't even like electricity on boat engines. Took the shut down solenoids off of 2 6-354
    perkins I had in a 1940 Elco. Replaced them with cables. The anti electronics opinion was driven home to me on a 125 ft offshore crewboat when 2 of 4 detroit 60 series
    shut down because the computers didn't sense adequate control voltage. These engines had air starters, and no alternators. the batteries were charged from chargers
    run off of the boats generator. I was just inside the Sabine River Jetties with rocks on both sides. The 2 engines that went down were both on the starboard side. Going back up the river wasn't too bad, but docking without being able to pivot or walk was a *****.
     

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

    FAST FRED Senior Member

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