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Cummins 480 CE Oil pressure

Discussion in 'Engines' started by Petepd, Aug 10, 2009.

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  1. Petepd, Aug 10, 2009
    #1
    Petepd

    Petepd New Member

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    The other day my Sea Ray 390 Motoryacht would barely get on plane due to a uncleaned bottom, and I was running it at about 2300 RPM hoping to knock some of the slime off the bottom. When I de-accelerated to idle speed the engine alarms went off indicating low oil pressure , which was about 20 pounds at idle. After a minute it came up to about 25 pounds and when running at 2100 RPM it was about 60 pounds. anybody know why it would drop off like that and what I should do to correct it? The oil is not up to the line but is not below the hash marks.

    Thanks, Pete
  2. CaptTom, Aug 10, 2009
    #2
    CaptTom

    CaptTom Senior Member

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    When was the last time you changed the oil/filters? Ever have an oil analysis done? Pump going bad? Did the engine overheat?
    BTW, hard to knock off the growth from the bottom by going fast. Better chance of removing it by cruising over a sand bar. lol
  3. K1W1, Aug 10, 2009
    #3
    K1W1

    K1W1 Senior Member

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    Hi,

    If the Oil Pumos have their pickups in the back I would go along with the Oil being bit low and it all sloshing forwards when you slowed suddenly.

    How much of an angle are you engines on?

    You might find that the full mark on the stick is not the actual full mark.

    CAT have a procedure called Calibrating the dipstick where you fill the engine with the correct amount of oil by measuring the liquid quantity as you pour it in and them you mark the stick accordingly. Not sure if other manufacturers do this but it seems like a good idea.

    There is a YF Member here who is a Cummins guy from California called Sbmar who should be able to answer your questions with some level of certainty.
  4. CaptTom, Aug 10, 2009
    #4
    CaptTom

    CaptTom Senior Member

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    As per K1W1's explainations, that's why you never change a dipstick from one engine to another engine without recalibrating. Good thing to check on new engines, too.
  5. Petepd, Aug 10, 2009
    #5
    Petepd

    Petepd New Member

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    The oil was changed about 14 months ago, but I've only put about 80 hours on the boat since then. The engines were not running hot. As to the other questions, I have not had an analysis done on the oil, aand I don't know about the pumps. And I'll keep the sand bar idea on the back burner just in case! ;) Thanks!
  6. K1W1, Aug 10, 2009
    #6
    K1W1

    K1W1 Senior Member

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    Hi,

    Instead of sanding it off you could try it yourself with a brush and dive gear or call a diver to do it for you.
  7. Marmot, Aug 10, 2009
    #7
    Marmot

    Marmot Senior Member

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    Did you decelerate rapidly? It sounds like low(ish) oil level and rapid deceleration simply moved the oil forward and the pump lost suction for a moment, just like K1W1 suggested.