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 is fixed with an outer enclosure and is adapted for securing to the machine. The mounting plate is 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 is 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 has a second porosity greater than the first porosity, and is fixed fluidly between the pressure-actuated valve and the central portion of the outer enclosure.