i had changed my blower oil about 400 hours ago and i had put in the dresser roots synth oil in it what is a good time to change what are the guys changing for hours with syn.
Yea, your blower is tough, you ain't gonna kill it with one brand or another of oil, there are records of running blowers 10,000 hrs without an oil change. You'll do more damage running it low on oil.
That said, the smart guys I know reccomend Mobil SHC 630 if you can source it.