Mailing List flyrotary@lancaironline.net Message #48475
From: Dave <david.staten@gmail.com>
Subject: Re: [FlyRotary] Re: Too much oil pressure.
Date: Sat, 03 Oct 2009 17:33:52 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
The rear stock (and replacement custom) oil pressure regulative valves are piston/spring assemblies inside a threaded case.

Take the case apart (unscrew it). Put in washers to compress the spring more than stock, reassemble.

George Lendich wrote:
Lynn,
How do you adjust the stock oil pressure regulator to higher than 71 lbs.
I haven't seen the insides but someone mentioned putting it in a press and squeezing it down a bit. I assume it compresses a spring, but it sounds like a 'quick and dirty' method of adjustment. Can you pull them apart and put in a spacer?
George ( down under)

         That would shorten the oil pressure lines to near normal, and
    remove what is causing the higher than normal pressure at the
    filter stand. The front pressure relief is set at 144 pounds. I
    bet the relief is standing open to some extent, the whole time the
    oil is warming up. At the other end of the oil pressure loop is
    the stock oil pressure regulator and it is not going to open until
    it sees 71 pounds or whatever it is set at. Once off idle (about
    600 RPM) the stock pump has some excess capacity and could support
    such a situation. So resistance to flow by the long runs and the
    cooler could be producing a huge amount of pressure. If you are
    measuring oil pressure on the engine, you would not see that
    pressure on the gage.
         So long as the engine is at idle or low speed this may not have
    been a problem. If the engine were to rev up a bit oil pressure
    could have gone to a bit over 144 pounds while showing 71 pounds
    on the gage.
         This is peculiar to Mazda, where the regulator is at the end of
    the system rather than inside the pump where it is supposed to be.
    Similar to FI reulators on the end of the fuel rail, that can blow
    apart and set the engine on fire.
         This must be a Renesis. The "O" ring would have blown out of a 13B.
         Lynn E. Hanover
     

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