mmattockx is correct, I read it some where, AND
Others that I highly respect in the RC community have also come to this conclusion by experimentation (real experts)
I personally have done no such testing, but I can learn from what these guys have done without doing myself
Any high quality oil will be just fine. Besides, I doubt that 99.99999% of RCer's will ever wear out an engine before it gets planted and needs to be repaired anyway

Yea, Wake Up Dick and Have Some Fun

Oh, buy the way, I am giving Penzoil a try now. That way I can compare it to some other oils I have tried, and one manufacturer even recommends it too. Dicks favorite will be tried next year.