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I agree with Tracy, John. Sounds a bit low to
me. Not dangerously low, but not certain I would feel comfortable flying
with it. I presume you are measuring your pressure at the old oil filter
location on the block and after the oil filter and oil cooler, yes? What
weight oil are you using?
Mine does not drop below 30 psi at idle, is 50 psi
by 3000 rpm and is 70 psi during flight.
Your 60 psi at 4000 is does not bother me that much
- but 15 at idle sounds low based on my experience.
Generally, I have found if you have air being
sucked by the oil intake, then it will take long to get the pressure up from
zero after start, no air leak and it jumps up as soon as engine
fires.
Now, the spinning shaft problem I had was
when I lost the key out of the oil pump shaft during reassembly and only the
torque of the bolt kept the chain sprocket driving the pump (for a while), it
finally started slipping and my pressure at idle drop to less than 20 psi.
I fortunately did not attempt to fly once I noticed that happening, checked it
out and found the key in bottom of the sump. I did not try to rev the engine and
see how much pressure I could get with a spinning shaft. But, if it is the
shaft spinning I would expect to see your oil pressure continue to slowly drop
as the shaft/sprocket wears.
However, have not tried to pull oil off for a
turbocharger as well as a gear box. So 'fraid I can't offer much in the
way of suggestions.
----- Original Message -----
Sent: Wednesday, January 05, 2005 9:26
PM
Subject: [FlyRotary] Acceptable oil
pressure
Leon and anyone
else who cares to comment...
The remaining
question with my installation is whether the oil pressure is acceptable, or
whether something actually wrong.
Everything has
been triple calibrated now, so I'm pretty sure of the following
readings.....
Start-up at 70F
ambient gets me 80 - 85PSI. Once the oil gets hot I'm seeing about 15 or
so at idle, 25 PSI at 2000 rpm, 45 PSI at 3500 rpm, and maybe 60 PSI at
4000. Talking about today with Tracy he felt it was marginal, and
was wondering if this might be normal with a combination of a turbo and a
redrive both taking pressure. Other possible causes he suggested were
Ed's spinning shaft syndrome or air being sucked by a leaking oil pickup.
I hate to remove
the engine (again) to check these items.
What do people
think? Anything else I can check?
John (no more soot
on the prop)
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