Quote Originally Posted by mbeach
Wait a minute...
3 piston rings, top to bottom
Compression
Compression
Oil Control/scraper

Crank case

Why exactly does oil need to drain through a hole in the piston/ring land in order for it to be returned to the crank case -shouldn't it drain down there on it's own with every downstroke of the piston?
That is what I thought initially, but my research into this subject turned up this interesting NASA report that addresses this issue ( albeit a different engine)

This is a good read.Especially pages 4,5&6.

http://naca.larc.nasa.gov/reports/19...ge00000004.gif