Mazda eventually got their engines to consistently last over 100,000 miles with the Renesis in the RX-8. The biggest thing is lubricating the seals; as a result

Mazda eventually got their engines to consistently last over 100,000 miles with the Renesis in the RX-8. The biggest thing is lubricating the seals; as a result all Mazda rotaries burn a little bit of engine oil to lubricate things, via a metering oil pump. That's the biggest reason why they struggled to keep emissions down.