An oil pump effects a pumping action to deliver oil from an inlet port to a first outlet port and also to a second outlet port. An oil supply passage is connected to the second outlet port. A regulator valve has a bore, a spool disposed in the bore, a pressure chamber, and a pressure admission port connected to the oil supply passage and communicating with the pressure chamber. A branch passage connected to the oil supply passage opens to the bore. The regulator valve also has relief port connected to the inlet port and opening to the bore, and a transfer port connected to the first outlet port. The spool disposed in the bore is moveable responsive to pressure within the pressure chamber between a first position in which the transfer port is connected to the branch passage and a second position in which the transfer port is connected to the relief port.