"Filtering all the oil" with a full-flow means that none of it gets filtered very well. Flowing all the oil the engine needs to keep itself lubricated through a filter as it leaves the oil pump is like trying to get a drink of water from a fire hose. It's much better to slow the flow down, run some of the oil through tight-mesh filter media, and strain out the fine particles, along with trapping the rocks, marbles and bowling balls that a full-flow filter is designed to catch. Lots of commercial engines like the old 855 cubic inch Cummins Diesel had both types- - - -a full flow to catch chunks big enough to damage bearings, and a bypass to strain out the tiny particles.
Jerry
