with external threads 64 for threaded engagement with a threaded hole 66 formed in the center of the cap 14 boss 62 may be provided with a hex indentation 63 for receiving a hex or other tool plate 60 extends in a somewhat planar configuration from the boss 62 to a position between the uppermost larger diameter spring coil 50 l and the underside of cap 14 upon rotation of the boss 62 in a clockwise direction plate 60 is caused to move inwardly to further compress the conical spring and thereby increase the cracking pressure of the check valve 10 the outer periphery of the plate 60 may be provided with radial protuberances 60 p to engage into openings 20 and provide indexing of the plate 60 as the plate 60 is rotated to adjust the cracking pressure the protuberances 60 p may be of the same width as the openings 20 or if smaller may be asymmetrically positioned to provide accurate indexing fig6 illustrates an alternative embodiment for free floating of the poppet 30 to assure uniform annular indexing of its o ring 34 on annular seat 36 specifically protrusion 42 is configured to achieve a conical apex point for universal engagement into a corresponding center seat 72 formed in a balance plate 70 the balance plate 70 assures that only a central force is exerted onto the poppet 30.