12a OMP mod (gravity feed ) ?
#1
#4
The OMP (Oil Metering Pump) really is a pump although it is of small displacement and has little suction lift. So as long as the oil supply bottle or tank is at some elevation above the pump,
(called head in pump talk) the pump will work fine.
If you are sure you will retain this feature, you can cut into the oil gallery that supplies the OMP at the front left corner of the front case and TIG in a dash 4 AN male fitting, and run a nice looking Aeroquip or similar line to the oil tank.
This is common on rotaries used in home built aircraft.
The object is to use an ash free 2 cycle oil (even a synthetic like Redline) in the top oil tank, and a straight weight synthetic in the oil pan. Synthetics do not burn cleanly, and this allows the best of both worlds lubrication wise.
If you tap that hole and install a bit of a screw instead of epoxy, you could remove the screw later and return the engine to stock operation.
If the engine is still apart, you can drill and tap this same oil supply gallery in the gasket surface of the front case. This screw could also be removed to return the engine to stock operation. The dash 4 fitting TIG welded in place, not so much.
The OMP does not provide quite enough oil volume for all out racing, and distribution is not great across the rotor face, so for racing just premix a name brand 2 cycle oil at 1/2 to 1 ounce per gallon of fuel. Leave the OMP in place and operational. When that tank of fuel is used up, you are back to stock again.
Lynn E. Hanover
Picture is a 3 rotor in a pusher aircraft configuration.
#5
ok so i have scrapped the omp completely and assembled back together again no i have a few questions on its operation , opening the front oil gallery i was able to see the actuator which adjusts the pump stroke ( i think ) its a simple shaft which resembles the eccentric shaft of an rotary engine except that the lobes are in phase and not 180 degrees apart , there is a pin which the actuator releases then the actuator is fully open , does this increase the stoke of the oil pump ? , and i have noticed that there is a small hole to the left inside the oil gallery and i am guessing this is the oil feed , so by plugging (divcon) the oil feed where the pump attached to the front cover and tapping a hole and attaching a fitting to the oil gallery plate i would be able to effectively feed oil in to the pump from an external source and into the oil gallery and thus in to the pump ??
i will post pics of the oil pump disassembly as soon as the pics upload
i will post pics of the oil pump disassembly as soon as the pics upload
#7
Here is a link to the RX-7 club page about Richard Sohn's oiling adaptor.
http://www.rx7club.com/showthread.php?t=810299
Here is a link to the adaptor as seen on the Rotary aviation web site (Real World Solutions)
http://www.rotaryaviation.com/oil_in...p_adaptors.htm
The lever turns a cam that limits the stroke length of the plunger.
These adaptors fit between the pump and the front case, and provide a place to plumb in a 2 cycle oil from a bottle on the firewall. Very clever. Can be removed to return the engine to stock.
Lynn E. Hanover
#8
yes i kno about that adaptor was just wondering after i saw the video if i could achieve the same thing for free with a mod , i could import this part as i live in the caribbean or i could try to mod the OMP i will do some more research and experimenting and will let u all know how that goes
#9
yes i kno about that adaptor was just wondering after i saw the video if i could achieve the same thing for free with a mod , i could import this part as i live in the caribbean or i could try to mod the OMP i will do some more research and experimenting and will let u all know how that goes
You can replicate this piece with a bit of 1/2" plate stock cut to the shape of the gasket and drilled to match the inlet port and a spiggoted tube, but not the case. Longer bolts to match and
another (home made) gasket.
Same thing.
Lynn E. Hanover
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