Not sure what you mean by the "old rotary engine", every rotary engine ever produced by Mazda cannot use synthetic oil. As for other gasoline engines, general aviation engines cannot use synthetic oil either. Why? Because GA engines are fueled with leaded gasoline and one of the few challenges synthetic oil is not up to is holding TEL in suspension. Ask Mobil; a couple of decades ago they came out with Mobil AV 1, an otherwise ultra high quality engine oil, even by today's standards, unfortunately, airplanes started falling out of the sky due to lead fouling of the rings and valves, and scoring of the cylinder walls.

 

Ok. But of course we're talking about gas car engines here. Rotary ? Yeah. As far a so know Mazda has ceased production of the rotary engine. Hence the "old". In that not in production anymore.

 

Ok. I stand corrected. Read an article that says Mazda will be re introducing a new rotary engine.

 

Not sure which article you're referring to, but while Mazda is still playing with the rotary engine, they have made no commitment to putting it back on the market. My bet says they never will. Why? In spite of the wonderful power to size/weight ratio of the Wankle engine, I rather doubt even Mazda will be able to cure the engine's thirst for fuel or its uncleanly exhaust.

 

Yes. They are unveiling in next years auto show. The new rotary powered R. Maybe Rx 9?

 

I'm laying odds they don't. I'm thinking the article you read is seriously out of date.