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lower rpm lower oil pressure

in 912 / 914 Technical Questions 12 years ago
Hi all,

I accidently put this item in General Discussion thread.

Normally when rpm increases the oil pressure will drop due to the pressure regulator: cone spring operation.

I have now the reverse. :unsure:

Or is there still air trapped after purging? The tappets were hard!

Bill already replied.

Jan

  • Re: lower rpm lower oil pressure

    by » 12 years ago

    Hi Jan,

    I believe one of the guys already suggested to change out the oil pressure regulator cone, spring and plug screw. That you should do and it could be the cause. I would do this first and then see the next suggestion below.
    That said if you increase throttle and the oil pressure drops then reduce throttle and it goers back up that could easily be a poor ground or earthing connection. I have run into this more than once and is easy to correct.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report

  • Re: lower rpm lower oil pressure

    by » 12 years ago

    Hi Roger and Bill,

    Thanks.

    1. checked ground MGL Xtreme EFIS: OK
    2. checked wire connection VD sender: OK
    3. checked spring+ball: OK
    4. mounted the engine hoods
    5. testrun engine: OK readings as before!

    What was the cause is beyond me. Perhaps when engine hoods are not in place wires gallop due to the propellor wind causing erratic readings. Have to test this sometime.

    Jan
      
    Report

  • Re: lower rpm lower oil pressure

    by » 12 years ago

    Hi Jan,

    The spring and ball could be the problem. Swap them out for the new plug screw, a new spring and the new pressure regulator cone. He spring with the ball bearing may be rubbing against the case housing. The newer setup helps eleminate that.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report

  • Re: lower rpm lower oil pressure

    by » 12 years ago

    Hi Roger,

    Sorry, forgot to mention that I have the new plug screw but with a ball. Should I replace the ball by a cone?

    Jan
      
    Report

  • Re: lower rpm lower oil pressure

    by » 12 years ago

    Hi Jan,

    Absolutely replace the ball. That and the spring was the problem. The ball allows the spring to flex sideways and contact the case. The new mushroom has a stem that goes down into the spring to keep it straight and away from the case. Th ball bearing can cause pressure fluctuations because of its design and the new mushroom fixes that with its design.
    The mushroom has a stem, a sharper cone shape on top with a hole drilled in it to keep it from sticking.
    I have so many ball bearings from these change out I'm ready to play marbles. :P
    We used to call them steelies when I was a Kid, but they were much bigger and a prized possession.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell

      
    Report
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