ORIGINAL: DarZeelon
No Greg, I was just crunching the theory...
The residual amount of surface oil, left in the bearings and even on the cam-lobes, for as long an idle period as one will endure, could just suffice.
After the .70FL used a sealed rear bearing that in theory, kept all the oil in the crankcase, away from the cams and followers, I could believe anything.
The Surpass engines with PCV have a small hole in the crank to pass lube into the cam box. The cam box is were the crankcase vent is. They use the same method in the new engines but it is plumbed internally rather than with the tube from the cam box to the intake manifold.
As far as sucking all the lube out of the crankcase, I just don't see it happening. Shortly after going to idle the manifold and crankcase pressures will balance. The small amount of circulation that does occur will be caused by blow-by. It's not like a vacuum cleaner.
I had an FL-70 apart recently. I didn't take many notes and I'm not sure if it had a passage into the cam box. One thing to note about the FL-70 and plumbing the breather to the exhaust. The nipple supplied to use in the muffler has a small passage. It's much smaller than the pressure fitting for the fuel tank.