[JFP in PA]

Originally Posted by southernstar

Consider 2 stroke engines - even though oil is drawn into the combustion chambers during each cycle in conjunction with both gasoline and yes, air, nevertheless the oil is still able to provide adequate lubrication. This is so even though in theory there would be a significant risk of 'aeration' with the movement of the pistons and piston rings combined with oil and air.

Even in a four stroke engine, wouldn't there be a risk of the oil in the cylinders becoming aerated, especially during the compression stroke? The oil is still able to lubricate or none of these engines would be able to function for any length of time. Again, it seems to me that the risk of aeration from a pressure oil feed to a bearing with NO access to air intake should not be a concern.

And Mike, oil is being forced into the crankcase regardless, is it not? Since the same amount of oil is being cycled through the engine, I just can't see how this would make things any worse. Or am I missing something? It also strikes me that if the oil is being aerated by the pressure oil feed to the IMS bearing, then the oil on the dipstick should appear foamy or frothy after a hard run. Certainly if it was too much to allow the anti-foaming agents in synthetic oil to overcome. I wonder if anyone who has installed DOF has checked their dipstick after a hard run and can comment on whether this is case.

Brad

There are reasons these engines have multiple air oil separators in them.......