Richard Schubert Posted March 27, 2009 Share Posted March 27, 2009 Actually the bypass valve controls the oil circulating inside the rotors. This allows the engine to warm up faster for emissions reasons. The oil injection is a separate system that lubricates the tip seals. It uses oil from the sump, causing two problems, the oil is slowly depleted and needs refilled more frequently, and the sump oil is generally not designed to burn cleanly eventually causing the seals to stick. Later RX models required a special oil to be used if you didn't want to void the warranty. For our purposes the oil pump can be serviced from a separate reservoir filled with clean burning 2 stroke oil, or the pump can be removed and the 2 stroke oil premixed with the fuel. Quote "We choose to do these things not because they are easy, but because they are hard." JFK Link to comment Share on other sites More sharing options...
SAF_Zoom Posted March 27, 2009 Share Posted March 27, 2009 To me, the Mazda rotary is NOT a proven power plant.... not by a long shot. The RX-7 twin turbo was at best a 30k mile engine, then it needed full replacement. We are not talking Mazda Miata 4 cylinder reliablilty here. The RX sports cars wear out quick (except for the old low power units of the early and late 80's). Today, the RX-8 is still having major engine issues. They wear out, even in standard street use, much quicker than piston counterparts. Consumer reports shows the reliability on the RX-8 is "poor" in the "Engine Major" category as well as the "Engine Minor" category. These engines wear out fast with low miles and regular street use. I love the rotary concept, and have owned a couple myself. They are just not a strong foundation to start an engine program with. Heck, if Mazda can't get them to be reliable in a 4 door sports car, then what chances do we have in an airplane? Although, 30k miles in a car is still approximately 1000 hours of running time, which may be acceptable to some. Guess you never owned a RX-7 or 8... I blew my 13b (in my RX-7) after it had more than 100 000 miles on it. This car was driven hard... hey never shifted until the little needle it 7000 RPM... But yes one rotor did blow... but it still drove on one rotor for more than a WEEK (thats about 50 miles per day) after it blew... So is it reliable yes... Quote Link to comment Share on other sites More sharing options...
SAF_Zoom Posted March 27, 2009 Share Posted March 27, 2009 I didn't want to get into this but you have stated this several times ..... so I will address it. The Rotary for the street has a valve that controls the cooling oil that is injected into the rotor chamber. In order to meet some of the standards set for American cars, this valve cuts off the flow of this oil until the engine heats up ...... then the oil flows. This causes premature wear on the seals located at the tips/corners of the rotors. This is one of the issues addressed. Tracy estimates a rotary TBO is close to 2000 hrs. Yes sir ........... Quote Link to comment Share on other sites More sharing options...
SAF_Zoom Posted March 27, 2009 Share Posted March 27, 2009 Actually the bypass valve controls the oil circulating inside the rotors. This allows the engine to warm up faster for emissions reasons. The oil injection is a separate system that lubricates the tip seals. It uses oil from the sump, causing two problems, the oil is slowly depleted and needs refilled more frequently, and the sump oil is generally not designed to burn cleanly eventually causing the seals to stick. Later RX models required a special oil to be used if you didn't want to void the warranty. For our purposes the oil pump can be serviced from a separate reservoir filled with clean burning 2 stroke oil, or the pump can be removed and the 2 stroke oil premixed with the fuel. And we have another winner..... Quote Link to comment Share on other sites More sharing options...
TMann Posted March 27, 2009 Share Posted March 27, 2009 All good information and all covered in Tracy's book ...... plus. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
macleodm3 Posted March 28, 2009 Share Posted March 28, 2009 Guess you never owned a RX-7I've owned two RX-7's, and both of them lasted well above 100k miles. I know the engine and its issues well. I had no issues with my 12A, although it only produced 100hp. My 13B with its stock 160hp had more issues. Tracy estimates a rotary TBO is close to 2000 hrs. Tracy is selling things, guys. Mazda's Miata engine does not break with low miles. Mazda knows how to build long life engines. The rotary has a lot of problems for street driven RX's, including the new RX-8. Check it guys, I don't care if you don't want to admit it, the RX's in the US don't last. So, Mazda would be selling RX's with 200k mile engines, if only people would be willing to fill up a stroke oil reservoir, that's what I'm hearing from you. Nobody here said a converted rotary wasn't a good idea, although I said that the stock Mazda enignes don't produce rated power for very long and wear out quicker than they should. Quote Andrew Anunson I work underground and I play in the sky... no problem Link to comment Share on other sites More sharing options...
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