In a lubricant delivery system for use in an air compressor having a rotatable crankshaft and an internal chamber accessible by removal of an inspection plate having inner and outer surfaces, a positive displacement fluid pump mounted in the internal chamber and fluid lines for conveying lubricating fluid from the pump to a removable filter mounted on the outer surface of the inspection plate. Pressure relief means are associated with the filter for relieving pressure above a set point, and a distribution ring is adaped to circumscribe the crankshaft for introducing lubricating fluid to the crankshaft and from there to areas where lubrication is required.