From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [FlyRotary] Radiator Caps.
To: flyrotary
Date: Tue, 03 Dec 2002 00:59:57 -0500
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Posted for "Ed Anderson" <eanderson@carolina.rr.com>:


> My cap is a stock Mazda which I believe is about 16 psi, but my pressure
> guage runs around 20 psi.  The cap is new as is the part it screws into.
> Looks like more gremlins to exorcise.

Careful what you read, Bill.  I used to read about a problem Tracy Crook was
having and within two weeks I would have the same problem - of course by
that time Tracy had figured out the problem and solution {:>).

    Since I have a "Plugs Up" installation, the entrapped air is even more of
a problem.  I have found that after refilling the system with coolant, I
first leave the radiator cap off and run the engine this permits most of the
entrapped air to simply come out of the solution and up through my radiator
fill tube.  You can tell how much entrapped air you have in the radiators by
feeling along the side tank.  It will be too hot to hold your fingers where
there is liquid and up to the level of the liquid, afte that there is just
air and the side tank is much cooler.  I find that after I refill my coolant
about  1/3 of the volume of each evaporator core is entrapped air.  After
running the engine for 4-10 minutes as fast as I can without blowing coolant
through the opening I put on the radiator cap.  I then run the engine up to
5000 rpm for 30 seconds or so. When I open the raidator cap I find about
1/2-1 pint of air. I refill with coolant and then  I close the cap and
repeat the runup.  Each time I will find a bit less air in the system. After
approx 3-5 times most of the air appears to be gone from the system.

Now for systems with the auto orientation, I am still reading that even the
RX-7 auto guys have probelms getting all the air out of their systems and do
much the same process.

For what it is worth I have tried to install a thermostat on three
occassions.  On all occassions, the  engine would overheat and I have never
been able to establish the reason for that as other folks with plugs up have
installed thermostats.  But, any how, it wasn't worth runing an engine for,
so I fly without a Thermostat.

My coolant overflow tank is a 2 quart capacity plastic container which is
fed from the bottom.  The level will vary approx 1 1/4" depending on whether
the engine is cold or hot.  Any coolant that pushes past the radiator cap is
of course trapped in the container then because the tube connects to the
bottom of the container and is always covered by coolant, once the engine
cools down the coolant is drawn back into the engine - but not the air that
came out with the coolant.  After a couple of flights there appears not to
be any air left in the system.

FWIW

Ed Anderson