I should mention that if anybody needs any Mobile Jet Oil II, I have cases of it.A company called Lube V makes all kinds of synthetic breathing air oils and will even custom blend to your specs. That is what I use in my Luchard h6 compressor in 30wt. They sell direct by the quart so no big expense. In my coenelius compressor I use Mobil jet oil 2 but when my stock runs out I will buy from Lube V as they make one specifically for the small compressors in the proper weight. I would probably not use motor oil as some of the additives may cause carbon fouling and may not be the best for breathing air.