My Rx-7 burns a lot of oil every time it starts, yeh who doesn't have that problem with high miles on a rotary. Sometimes enough oil leaks through the seals that it clogs the ports no phut phut noise when u try to start. There is still pretty good compression in both the chambers. I'm Just wondering what synthetic oil will do for a rotary. And if I should go up in weight to 40, cause that should make it harder to leak through the seals, or is that to heavy for that engine to handle.

Someone correct me if I am wrong, but putting synthetic oil in a rotary will result in a bad thing. The reason for this is because the engine is like a 2 stroke motor, it injects some oil into the rotor housings so that the apex seals dont dry out and burn up. By putting synthetic in, you are going to clog that all up, and fry the seals.

I cannot forsee synthetic oil doing anything but making your oil-burning issues worse. The same weight synthetic oil is probably going to be thinner vs. the dino counterpart.



You have already suggested moving up to a different, heavier weight which is an option. You might consider the fact that the parafins in a heavier weight oil can freeze and accelerate oil break-down when subjected to extremely cold temperatures.



I run synthetic oil in one of my cars and have not noticed a negative difference.

Yeh but how will it clog the injectors

the imperfections in dinosaur oil help the oil seals swell and prevent leakage.



Synthetic oil has less imperfections so it would make your burning oil issue worse.



It is possible it could be a leaky oil injector that is seeping too much into the combustion chamber and causing your smoke. Hopefully that is the case.

I have heard that synthetic oils are better at finding their way past seals than are dino oils. My first hand experience with a couple different cars would seem to confirm this.



I would suggest dino oil in 20W-50 weight for your seven.



There has been a lot of discussion about the possible consequences of running synthetic in a rotary. I believe the final verdict was that it was unlikely to cause any problems, and that it helps reduce engine wear. Nevertheless, I choose to run dino oil in mine. If you don't have the oil metering pump and you run premix, then there really is no question that synthetic is better from a purely lubricating standpoint.



Hope this helps.