OVERKILL
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To add to the above, how common a bypass event is in an application would directly relate to oil viscosity used, oil volume in the system and the headroom above the pump.
Think of the act of starting. If you have an engine like a Modular with a stock pump that is relatively high volume/high pressure and it has a lot of things upstream of the pump that can bleed down, during a start-up event, the lack of pressure upstream of the media may allow for a brief moment of filter bypass until the engine becomes fully engulfed and the differential is reduced. During this time, if Ford's diagram is correct (and what I am describing here appears to be what they are illustrating) there is the potential for what has settled in the bottom of the can to be washed up and through the bypass into the engine.
I don't think it is a concern for an engine that is already running and may, under WOT or something, experience a bypass event, as anything in the bottom of the can would probably be stirred up by the flow of the oil in the filter and be stuck to the media at that point. But when the engine has sat and things settle, that's where the particulate that was pressed against the media due to flow settles out and ends up on the bottom of the can. This is the stuff I believe Ford is talking about.
Think of the act of starting. If you have an engine like a Modular with a stock pump that is relatively high volume/high pressure and it has a lot of things upstream of the pump that can bleed down, during a start-up event, the lack of pressure upstream of the media may allow for a brief moment of filter bypass until the engine becomes fully engulfed and the differential is reduced. During this time, if Ford's diagram is correct (and what I am describing here appears to be what they are illustrating) there is the potential for what has settled in the bottom of the can to be washed up and through the bypass into the engine.
I don't think it is a concern for an engine that is already running and may, under WOT or something, experience a bypass event, as anything in the bottom of the can would probably be stirred up by the flow of the oil in the filter and be stuck to the media at that point. But when the engine has sat and things settle, that's where the particulate that was pressed against the media due to flow settles out and ends up on the bottom of the can. This is the stuff I believe Ford is talking about.