An oil filter assembly is disclosed for a machine, such as an internal combustion engine, that has an oil output port and an input port. A mounting plate is fixed with an outer enclosure. 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 portions of the outer enclosure. Oil passes through the pressure actuated valve only when an oil pressure differential between the peripheral and central portions exceeds a threshold pressure. A secondary filter has a second porosity greater than the first porosity, and is fixed between the pressure-actuated valve and the central portion.