Message-ID: <001101c3fe64$64ab04a0$2402a8c0@edward>
From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-3050160@logan.com>
Subject: Re: [FlyRotary] 13B smooth running issues
Date: Sat, 28 Feb 2004 20:36:03 -0500
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Glad you got it running, John.

One thing that even the RX-7 Rotary guys have told me is that even with the
engine in the auto orientation, you must burp the engine and continue
refilling it as you work more air out of the system.  DO NOT (a little late
I know) rely on your coolant temp during the initial coolant filling phase.
If there is insufficient coolant to keep the temp sensor covered then it
will erroneously read much lower temp than exists in the engine.

What I do to check the burping of the engine to get the air out, is after 30
seconds or so running, place your hand on the radiator tanks.  It will be
noticeably hotter from the bottom up to where ever the coolant level is.
When I first refill my engine the coolant level generally fills only 2/3s of
the tank.  After a short run the coolant level is lower in the header tank
and I simply pour in more coolant.  I continue this and check  for the hot
area of the side tank of the radiator to move up the side indicating more
coolant and less air.  Generally it takes me 3 runs to remove 95% of the
air.

It could be your thermostat,   but I suspect part of the reason is that the
thermostat may  not open if its sensor is not bathed with hot coolant.  In
other words your coolant level can be too low for your thermostat to work
properly.  I presume you are using a stock Mazda Thermostat OR if not that
you have plugged the 1/2" hole inside the waterpump/thermostat housing.
Racing Beat reports that if you do not plug this reciculation hole, you can
lose 20% of your cooling effectiveness.

Best to ask Tracy, but if processor "A" is running, my guess is that there
could be a miswiring or a lose wire between your controller and the EC2 main
box so that when you switch processor "B" never gets the message.  Just a
guess.

The engine cycling like that makes me thing of a "lean surge" the engine
runs up to 3000 where it encounters (for whatever reason) a lean region in
the fuel map, this causes the rpm to die back to 2000 or so where it finds
an adequate fuel Map mixture whereupon it again starts to accelerate until
it hits the lean regions, repeat, repeat.  I don't know if your "gasping
sound" might indicate an air leak or not, but you might check.

While its possible you could have damaged your turbo, I really don't think a
few minutes of running if at modest boost would do it.  The turbo is cooled
by both the oil and coolant (in fact is only fairly recently that most
turbos had water cooling).  I would make certain that I had adequate oil
flow to the turbo as that will cause it to seize faster than anything.
Also, I don't know if the turbo would cause that much back pressure at those
rpms.  Did you ever notice any boost?

Regarding the oil pressure - are you certain that you have the oil filter
rigged properly?  If the filter hoses are installed backwards, you

1. Will likely not get oil flow - I presume you are getting some or you
would have seized the engine by now - but people have installed them
backwards and the oil pressure finally blew holes in the rubber backvalve
and delivered some oil flow

2.  Where is your oil pressure sensor located?   My oil pressure reads 80PSI
above 4500 rpm and that is after the oil pressure has dropped going through
both the oil filter and oil cooler.  If you have your pressure sensor
located near the oil pump oil exit or before your filter and cooler, you may
well read close to 90 -100 psi.  I presume you have the stock oil pressure
regulator and not one of the high pressure racing ones.

John, I would do a couple of things before proceeding to run the engine.

1.  Make certain you have adequate coolant, keep pouring in coolant after
short runs.  Check the progress by touching the side tanks of the
radiators - carefully don't burn yourself.  .  I wouldn't remove the
thermostat at this point if it is a stock Mazda RX-7 one as then you would
then need to plug the 1/2" recirculation hole in the water pump. Don't trust
the temperature sensor until you are certain it is sensing the coolant
temperature and not the internal air.

2. Take care of the coolant and any possible oil problems ( I would
unconnect the oil feed to the turbo and crank the engine and make certain
that oil is flowing out that line).

3.  Once you are convinced 1 and 2 are OK then on to the lean surge cycling.

Hope some of this helps

Ed  Anderson