Richard Sohn wrote:

The RX7 manual states the metering pump performance check with engine

RPM,

run time and amount of oil injected.
Last week I build an adaptor to put inbetween the pump and the engine,

run

it with an electric motor at the right speed feeding 2stroke oil at 6"
gravity. The output is as required by Mazda.
As soon as the design is completed I will need somebody to run it on an
engine, because I do not have one running at this time.

Richard Sohn.

The Mazda pump puts out oil as a function of both RPM and throttle

opening.

What RPM is your electric motor running at?

Paul Lamar

My electric motor is running at 1000RPM, which is 2000 E-shaft reduced 2:1

by the pump drive.

Richard

You need to run that pump at the same speed the Mazda pump runs at when the

engine

is running 6000 RPM WOT. That is when the apex seal oil requirements are the
highest. The first job of the apex seal oil is to cool the cast iron seals.
If you run ceramic seals you might be able to get away with less apex
seal oil as ceramic seals can operate up to 1000 degrees C. The
strength of the material surrounding the seal slots in the iron rotors
could also be affected if this area of the rotor runs too hot.

Paul Lamar

Paul,

Is the 'cooling the cast iron seals' with the oil injection due to reduced
friction,
or due to actual cooling effect?  If only cooling, but not actually lubrication,
would a coolant injection (water-methanol, for example) work as well,
besides the
intercooling effect helping for very high allowable MAP.

I would guess that the lubricationg effects, which would reduce the seal
tip temp, and not so incidentally, the rotor housing wear would be the most
important.

Bill

Quote Mazda SAE 900036: 

The sudden increase in seal temperatures indicated to the left
of point B indicates constant metal temperature. End of quote. 

>From this
I assume most of the seal temp comes from combustion gases. I think it was Jeff
that pointed out the apex seal is the first part that opens the peripheral exhaust
port forcing all combustion gases to flow right past the apex seal.

The latest computer controlled oil injection  pumps take into consideration
water temp as well as intake airflow and RPM.

The page is brought to you by the miracle of a dithered gif :-)

Paul Lamar
 
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