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Question about oil pressure and when it bypasses

in 912 / 914 Technical Questions 6 years ago

  • Re: Question about oil pressure and when it bypasses

    by » 6 years ago

    At low RPMs, the Oil pump is able to acquire and deliver more oil to the engine than the engine can use and the regulator bypass that Oil back to the Inlet of the Oil Pumps for reuse.
    The Inlet pressure goes up as does the overall system pressure.
    As the engine speed increases, the Oil pump delivers even more Oil but while the engine will also use more oil, it is not in proportion to increased flow.
    The regulator is now bypassing more oil than it did at idle and the Oil Pressure goes UP slightly.

    If the inflow is restricted, the Oil Pump may not be able to get enough oil to keep up with the increased demand.
    The Oil Pressure regulator stops bypassing, and the pressure reduces to the point where the engine is only using the amount of oil being delivered.
    As long as that pressure remains above 30psi, Nothing bad happens.

    Higher Oil pressure above 30 psi is not required.
    There is always the impression that "More is Better".
    Consider it like you are taking a shower and the showerhead delivers enough water that you are thoroughly soaked.
    Now if you were to increase the water pressure and flow rate or even added a second showerhead;
    Would you actually be more soaking wet that you were in the first place?
    There is a point of diminishing returns.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

      
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  • Re: Question about oil pressure and when it bypasses

    by » 6 years ago

    Bill, in your previous message you talk about the engine "using" oil. You say it "uses" more oil at higher rpm. Can you please explain this reference to the engine "using" oil?
      
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  • Re: Question about oil pressure and when it bypasses

    by » 6 years ago

    Ok, next step is to check for restrictions in the inlet side of pump.

    The first couple videos, I tested when temps reached 120 f. Those tests on the electric guage showed 50 psi at idle then going down to 30 psi at 4000 rpm.

    Since I have a thermostat installed (I believe they open at 180 f), I can rule out the hoses that are on the back side of the thermostat and connected to the oil cooler.
    I am correct in my logic?

    Thanks!
      
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  • Re: Question about oil pressure and when it bypasses

    by » 6 years ago

    Bill, in your previous message you talk about the engine "using" oil. You say it "uses" more oil at higher rpm. Can you please explain this reference to the engine "using" oil?


    By "Using" I mean Utilizing.
    The Oil is supplied under pressure to lubricate the various Bearings, Journals and other moving parts.
    As the engine turns faster more Oil pases through these parts and is "Used".

    USED, Not to be confused with Consumed.
    USED in the same sense that you body "Uses" Blood over and over again to support its functions;
    The Engine "Uses" Oil to lubricate its parts.
    And it USES (Utilizes) more Oil the faster it goes.

    <><><>
    English is such an Ambiguous language. ;)

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

      
    Report

  • Re: Question about oil pressure and when it bypasses

    by » 6 years ago

    ... Since I have a thermostat installed (I believe they open at 180 f), I can rule out the hoses that are on the back side of the thermostat and connected to the oil cooler.
    I am correct in my logic?...


    Heavens, NO!
    As the temps go UP more OIl Flows through the Cooler which may be the source of the blockage.
    Do Not Rule out ANYTHING until it has been confirmed that it is not the problem.
    And even then, do not rule it out, just move it farther down the list of possibilities and be prepared to revisit it if future evidence warrants.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

    Thank you said by: Aaron
      
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