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Hi John,
Don't have my REW FD engine manual here at home
(Don't want to quote figures off the top of my head). However, 60 PSI
seems OK at those revs (4,000). What do you get up around 5,500 -
6,000 RPM? That's the critical issue. Anyway, will get back to
you when I have consulted the manual. (Anybody else got an FD workshop
manual handy?).
It's not really the pressure that matters so much
as the ability of the pump to supply sufficient volume. The FD pump is
quite big, and has the capacity to pump enormous volumes of
oil. As somebody else said, it's designed to feed two
turbos, so it shouldn't have a problem feeding one turbo plus the
PSRU.
I'm currently running in a Series V turbo
engine. It is mild ported, and has a tricked up early model
dismantleable style regulator. It will produce 100 PSI above 6,000
RPM, but it has about the same PSI as you have at the lower RPM
ranges, once the engine is warmed up. Again, I don't have any
of my manuals here so I can't tell you exactly what to expect from the different
stock reguilators.
Apart from a leaky pickup gasket, or if the
bolts were left finger tight (you have to be REAL careless to have this
happen) it is possible to have a fractured oil pickup pipe (rare
but it can happen), I've also seen blokes leave the oil pump bolts loose
(again usually finger tight!), or not stake the oil pump shaft lock washer
(just carelessness), or the Woodruff key wasn't located correctly (Ed's
issue! - REAL easy to do - happens to me about every second or third
engine). Sometimes it takes two or three goes to get it in. They
are real small & fiddly You must ALWAYS double check - use
strong light or a torch to make sure that you can see the key is in the
correct place once the sprocket in on on the shaft, before
fitting the nut & lockwasher.
I also assume you used the white nylon backup ring
that goes with the O ring on the outlet from the front housing to the front
cover?? I also assume that you used the correct O ring?? Early (pre
'85) engines just has the O ring and the gasket. I've had these blow out
at times ( usually with tricked regulators in race engines). I developed a
technique where I stopped using front cover gaskets for this reason. Just
a much thinner O ring and RTV sliastic. Never had a failure
since. But all this is a thing of the past with "86 on
engines. Mazda got smart, and used the nylon back up ring to contain
the O ring, instead of just the gasket material.
One operational thing we have found in race
cars is that if the sump is overfilled, and/or we are not using a baffle
plate (a sheet of alloy that goes between the sump & the bottom of the
motor), the oil can get whipped into a "milkshake" (emulsion) by the front
counter weight. The emulsified oil will cause the pump to cavitate,
and then you get fluctuating/dropping oil pressure. So make sure you have
the correct length dipstick, and the sump is not over-filled.
I think all aero engines should have an alloy
baffle plate. During descent, the engine is still turning at
reasonable RPM, even though the throttle might be nearly closed. Oil
in the sump will tend to migrate up into the front cover (just like a car under
brakes). If the counterwieght gets a chance, it will take great
delight in making a caramel or chocolate (depending on how clean the
oil is) milkshake out of your lubricant. If you happen to need
to get back on the noise in a hurry, you might just have oil pressure
problems.
Anyway, there's my baker's dozen or so Brass
Razoos for today.
Cheers,
Leon
----- Original Message -----
Sent: Thursday, January 06, 2005 1:26
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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