Help me understand this: The flow from the 2 passages hit 'head on' (even though they approach the joining point at right angles to each other) and somehow stop each other? That is what they would have to do if the result is "you won't have oil pressure."
But what happens to make the pressure at that point NOT force oil on into the main oil passage? There WILL be full, no-flow pump output pressure at that point if there is no net oil flow.
At best, you can only claim that some turbulence occurs, but turbulence is a feature of flow.... so if you claim turbulence, then that means that there IS flow and so pressure into the engine can't be zero.
The pressure at that joining point will become a certain amount below pump pressure output and is going to be dominated by the relatively smaller pressure drop in the direct passage. If you could measure flow resistance through that direct passage (R1), and through the filter and its passages (R2), then then resulting overall flow resistance would be approximately R1*R2/(R1+R2). (This is the standard first-order resistance formula for 2 parallel paths, and applies to heat flow, electric circuits, and simple fluid flow.) Any added resistance due to turbulence would be added to that overall filter+ passage flow resistance. But to stop flow and have zero engine pressure, the turbulent resistance would have to be infinite, and since you can't have turbulence without flow, that can't happen.
I'm just trying to explain why the flow and pressure won't be zero.
