----- Original Message -----
Sent: Wednesday, December 18, 2002 6:41
PM
Subject: [FlyRotary] Re: water
pressure
Where is your pressure sender located,
Peter?
Pressure variations are bothering me too, but the
engine keeps running well
Yvon.
It is near the pump output but I may try moving
it to the plug used for car heater line at the other end of the
block.
What variations do you see?
Peter
My engine is a 1986 13B. At first, I did not have
a coolant pressure gauge. My coolant temp sender was located in the coolant
pump body close to the thermostat. Once I had the air out of the system, it
would maintain pressure for long periods, several days and more. When I needed
to remove the pressure cap on top of the pump, coolant would burst out under
pressure, so there must have been some air left in there. Oil and coolant
temps had to be monitored at WOT climb but would stay close to 200F at cruise.
I have always used a thermostat and a ~one litre coolant reservoir connected
to the pressure cap. When cold it is ~one quarter full. When hot, it is
9/10ths full. Also I have a canopy defroster which takes hot coolant from the
heater outlet in the rear housing and returns the coolant to the pump near the
thermostat.
Later, I moved the temp sensor to the rear
housing where Mazda had its temp sensor. Then I installed a coolant
pressure guage and put the pressure sensor in the front housing on the
sparkplugs side. There is a convenient threaded hole there for a pressure
sensor. Then, I connected the hot coolant outlet on top of the rear
housing to the top of the coolant pump body. So now, at ambient temperature,
engine cold., there is no pressure in the cooling system. I can remove the
pressure cap and loose only a few drops of coolant, negligible volume. When I
start the engine, the gauge shows no pressure for long minutes, 10
sometimes 15 minutes. Coolant pressure appears to be proportional to engine
rpm, but I am still checking on that. The max coolant pressure I have seen is
about 10-12 psi at 5500 rpm. in cruise. Temperatures are lower, both at
WOT climb and cruise. Oil ~190F (I wonder if there is a temperature regulating
mechanism inside Mazda's oil cooler) and coolant ~180F. But that may be
due to colder weather. Cloudy and cold around here, at this time of
year. (Sherbrooke, Québec.) The overflow bottle (coolant reservoir) performs
as it did before, so no worry there.
So, coolant temperature has come down and
that is more important to me than coolant pressure. We will see next summer if
my cooling system is really more efficient.
So, I was hoping that the oil temperature
would come down also to about 170-180F. My Mazda oil cooler in
installed upside down and I wonder if that could impede its cooling
function.
MERRY CHRISMAS TO ALL!
Yvon Cournoyer.
Rotary Powered Zenair Zenith. (CH-200)