An oil filter assembly is disclosed for a machine, such as an internal combustion engine, that has an oil output port and an oil input port. A mounting plate may be fixed with an outer enclosure and may be adapted for securing to the machine. The mounting plate may be further adapted to conduct oil from the machine into a peripheral portion of the outer enclosure, and then returning oil from a central portion of the outer enclosure back to the machine. Oil may pass from the peripheral portion to the central portion through a primary filter having a first porosity. A pressure-actuated valve may be fixed fluidly between the peripheral portion and central portion of the outer enclosure. Oil may pass through the pressure-actuated valve only when an oil pressure differential between the peripheral portion and the central portion of the outer enclosure exceeds a predetermined threshold pressure. A secondary filter may have a second porosity greater than the first porosity, and may be fixed fluidly between the pressure-actuated valve and the central portion of the outer enclosure.