Abstract: A pump valve for use with positive displacement/reciprocating pumps. The pump valve includes an adapter, valve body, disk, spring, and retaining ring. The adapter is driven or pressed into the fluid end of the pump and includes an annular interior threaded surface to receive a mating threaded neck of the valve body. The valve body includes the neck, trunk having a cavity therein, and an integral valve seat inside the cavity of the trunk. The disk has a diameter slightly smaller than the internal diameter of the cavity so as to fit snugly therein and seat on the integral valve seat of the valve body. The spring is coiled from a first coil of smallest diameter so that each successive coil is of an increased diameter to a final coil of largest diameter. The spring is inserted inside the cavity in the trunk and contacts the disk. The spring is compressed so as to fit entirely within the cavity. A groove is cut in the wall of the trunk on its internal circumference so as to receive a retaining ring.