I've been recently approached by a local amsoil distirbutor and he has been pushing me for quite some time now to run 0-30 syn oil. But I have been hesitant for mainly 2 reasons...1)I'm new to the whole rotary scene so I don't know what will happen if I do run that weight oil, and 2)nobody can give me a yes or no answer...it's always "i dunno, but I wouldn't". Currently I am running 20-50.
After talking to several reputable rotary engine builders(i won't mention who), they all told me that I should be fine running 0-30 oil. The general agreement was because technology isn't what it used to be back in the day. The viscocity rating generally has nothing to do with the chemical properties of the oil and it's ability to lubricate and protect moving parts. It's basically there to tell you how thick the oil is. After hearing that I'm a little more relieved to finally get a more definitive answer.
I just want to know what you guys think about this and what you guys are running?

 

stick with the 20/50 IMO

if it aint broke don't fix it.... if 20/50 works well in your motor, then don't bother wasting your money

the viscosity of the oil also determines how well it will perform under thermal conditions..... rotaries run hot, its in their nature.

the hotter oil gets, the thinner it will get and the less protection against friction it will have, synthetic or not. once oil gets to a point where it is thin enough to foam making the oil useless, since there is air, there is no oil providing lubrication.

IMO i would never run anything less than 20/50 in most climates, and 10/40 in colder climates

 

Never run anything below 10w in the rotary, anything lower gets too thin for it when it's up to temp.