George, you make the spring effectively
stiffer. Some have done this by adding spacers inside the regulator housing to
shorten and make the spring stiffer and offer more resistance to opening. This
in effect increases the amount of oil pressure needed to push the valve open.
You could of course add a stiffer spring.
Ed
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of George Lendich
Sent: Saturday, October 03, 2009
5:18 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Too much
oil pressure.
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?
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.
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