2 Running rich.  Because it is so hard to get the engine tuned, I am probably running very rich (the only way to keep it running), especially at low RPM.

Let me say first that I have never worked on a turbo rotary. I have worked on many NA rotories.

 

 Many of the kids hammering on turbo rotaries use solid corner seals, and many of those use aftermarket corner seals that seem to hold up to some detonation.

 

I did use the two piece seals a few times, and without the rubber plug. Because it will fall into the engine when used with some port shapes. I had one weekend go down the drain when one of those two piece seals broke through the thin part. I never went back to them. The point of the rubber thing is for better low RPM emissions (sealing). As time passes, they become hard and useless, so that feature is of no value in aircraft.

 

I have never seen a broken solid seal.

 

The failed side seal is also unusual to me. I have been gifted many engines that had badly worn side seals to the extent that the sealing surface had mushroomed into a "T" shape, and the end gap had opened dramatically, yet the engine had kept running.

 

I run more oil than is required at 1 ounce per gallon for operation above 9,000 RPM. I do get oil dilution at this mixture and change oil often. After every two races. The whole system holds 2 gallons.

 

This is Redline 40 wt. synthetic racing oil for the storage tank and Redline 2 cycle synthetic in the fuel. I use any 93 octane motor fuel without alcohol. Oil pressure is 100 pounds. These were recommended by engine builder Daryl Drummond. He does not like the low octane fuel, but I have no problems at all with it.

 

The Redline is very clean burning even at these rich mixtures.

 

 

 

So, what happened?

 

I think the side seal was broken during assembly of the engine. I have done it (years ago) and I have seen others do it. As in raising the crank to install the center iron. Or lowering the rotor onto the iron. It happens.

 

Over time the broken gap gets bigger and leaks more.

The requirement for overich mixture for starting and idle, is typical of poor sealing.

 

Side seal failures due to detonation tend to be near the ends of the seal, not dead center on the rotor. NA engines just about never detonate, so its not a problem I get to see in my engines.

 

I clamp the stack together as I build it up. When I install a rotor, I can rotate the engine to near normal attitude and have less of a problem with seals getting away from me during this critical operation.

 

I start off with zero end clearance on the side seals. The end of the side seal is pushed along by the corner seal, and the end of the side seal wears a notch into the corner seal in short order, so that some clearance appears soon after start up. This also helps on assembly, because I can hold all of the seals in place with a bit of sliding pressure on two side seals with a finger tip on that corner seal. With the stock clearance, it is difficult to hold all of the seals in by just pushing on one. I also use wheel bearing grease on everything just to be sure that nothing comes adrift during assembly.

 

Remember that this advice may be worth what you paid for it.

 

 

Lynn E. Hanover