ORIGINAL: SilverSwallow
He's talking about the amount of fuel used in relation to the size.
Diesels = Less fuel used, but same amount of oil needed for engine size = richer oil mixture
i'm glad you explained that...i was very confused!
however, i think the dynamics of friction ranks higher than the volume fractions
ORIGINAL: chevy43
I dissagre somewhat about the amount of fuel determins the amount of lubrication. I see it as an oil film on all moving parts based on the % of oil in the fuel. More or less fuel going through the engine doesn't change the oil film on the parts. Once the oil film is on the parts it takes very little to maintain the same film.
Since the bottom end doesn't get very warm I don't buy the cooling argument either. Sorry to be hard headed but so far I can't see the logic behind less oil for a ball bearing engine because the rod should need the same oil film on either engine...
In fact I have some Davis ball bearing fuel and it is so thin I won't run it without extra oil even in a BB engine. The piston and cylinder need the same oil too. Oil also helps seal the piston. Better too much than not enough!
i think you are right on the first statement - the % of oil in a drop of fuel from a gallon is the same as the % of oil in the whole gallon.
the cooling thing - i'm gonna go with it does cool. otherwise, it seems it wouldn't make the film and stick...it'd just burn up. less oil in a ball bearing - you make a valid point about the con rod. i'm just not sure if the ball bearing itself would require less oil, and then the "extra" oil could be used by the rod...especially true of sealed bearings.