Restarting Old Engines

Discussion in 'Diesel Engines' started by mydauphin, Apr 24, 2018.

  1. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    I have a couple 671 NA in my boat that I haven't run in like 8 years. They were in good shape before I ignored them. There is some surface corrosion here and there, but don't know where to start in reviving them. Any thoughts are welcomed.
     
  2. PAR
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    PAR Yacht Designer/Builder

    Clean out the fuel delivery system, check: air filter/arrestor, oil level, etc and send some fire to that 'ol gal. I'll assume these are a couple of Detroit Diesels or do you have a gas Chrysler (5.2 liter I think), found in many Ram pickups? The situation is the same for both, run some basic checks, looking for oil in locations you'd rather not have any, clean the fuel system (pull and blow out line, filters, etc.), supply fresh fuel and give it a try. What I do is the above, but if the engine barks or other wise sounds like she wants to fire or actually does, I'll let it run a few seconds, waiting for lifter noises and stuff to subside, then I'll suit it right down and do a more comprehensive set of "tune up" checks.
     
  3. mydauphin
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    mydauphin Senior Member

    They are DD's - My worries are more about corrosion in cooling system than anything else. Should have mentioned that.
     
  4. PAR
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    PAR Yacht Designer/Builder

    If just starting them up after a long sleep, you don't need to do much, just get them to fire on clean fuel and fresh air. If truly concerned, change the oil, filters and the usual routine maintenance you'd do after a few hundred hours of service. The cooling system can handle a few minutes of running time, while you get them purring smoothly again. You can go back, do a flush, maybe even a boil out, depending on what type of cooling system you have. Ditto this on the fuel and all the other systems.
     
  5. mydauphin
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    mydauphin Senior Member

    Fuel should not be an issue since they were run dry. And tanks are new. Thanks
     
  6. Barry
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    Barry Senior Member

    I had heard a rumor that the over time the rings in contact with the cylinder can produce some localized corrosion and when you start an engine that has sat for a long time, they stick and when you turn it over, the rings can break.
    To lower the chances of this to happen, the procedure was to take an extremely light penetrating oil and let it sit in the cylinders for several days, then manually turn the engine over.

    Also, if the engines are worth a lot, you could find an oil port that you attach say an 80 psi pump up to and pressurize the system with a light oil, to try to prelube the system.
     
  7. PAR
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    PAR Yacht Designer/Builder

    A prelube can be a good idea as would penetrating oil in the cylinders, though if there's that much moisture inside the crank case, you likely have other issues. Fuel, even if run dry when shut down, can leave residues that block little passages like inside injectors, so I usually try to clean the system first. On high pressure systems like yours, this is a less a problem, though particulates can be problematic if past the last filter.
     
  8. mydauphin
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    mydauphin Senior Member

    Great idea, I will treat them like engines that got flooded. On DD's I can take out side plates and spray light oil into cylinders. Now have to figure how turn engines manually.
     
  9. Lepke
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    Lepke Junior Member

    To manually turn over the DDs, many older DDs have a ratchet front pulley that fits a special wrench. Usually I find the wrench on DD equipped boats. Handle about 3' long with a round end that matches the pulley end. If necessary you can put a length of pipe over the handle to extend it.
    I've started many long sitting diesels. My family had a business renovating mothballed ships. Usually flushing the old fuel out of the lines, checking rockers and injectors for proper movement and then bar over the engine was all I did before starting. In Florida it should be warm enough. Rings can contract from long storage and take a warm up to reseal. IF the engines have block heaters, warm for a couple hours. A small amount of ether is ok, but don't run the engine on ether. Too much ether produces very high pressures and can crack rings. I've been running DDs since the early 1960s. They rarely give problems after long sits. The big issue is making sure the injectors aren't frozen or stiff and the linkage moves easily.
     
  10. 7228sedan
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    7228sedan Senior Member

    If I remember correctly, there was a recommended process for the 53 series to remove the valve cover(s) to pour oil over the valve train after a health sleep (30 days or more).

    Not sure if that also applies to eh 71's.
     
  11. mydauphin
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    mydauphin Senior Member

    All good advice. Thanks, What about cooling system side?
     
  12. PAR
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    PAR Yacht Designer/Builder

    I think you're over thinking this . . .
     
  13. Lepke
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    Lepke Junior Member

    It doesn't hurt to check the raw water impellers. They're probably ok and maybe in excellent shape. DD impellers are bigger and hold up better than you find on typical yacht engines. I pull my impellers 1-2 times a year to look for cracks or signs of too much wear. Then I use a finger of waterproof grease to lube the shaft and housing insides. Helps to seal for the 1st start to draw water quickly. It's in the old DD manuals that way. I get about 5 years - 2500 hours out of my impellers. Then they're still are good for spares.
    The coolant, oil, and filters are ok for starting. Check the valve rockers for easy movement, but I'd adjust the valves after warm. My current boat sat 6 years w/o care or any mothballing. 2 - 671 naturals. After a quick check and some block heaters (winter in BC) they started right up on the fuel in the rails. DDs were one of the main reasons I bought this boat.
     
  14. mydauphin
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    mydauphin Senior Member

    GOOD TIP, THANKS
     

  15. BlueBell
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    BlueBell Ahhhhh...

    So, did it fire?
     
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