- A complete turn of the pump shaft thus gives a complete cycle. ( Inlet and Delivery ) for each piston. d) Delivery : - The manufacturing tolerances of the pump parts are such that it is necessary to position the piston accurately in its sleeve to obtain the correct delivery. - This setting determines the piston stroke, and thus its maximum delivery. - The setting consists of allowing a clearance of 0.5 mm between the disc valve and the piston crown. achieved by the use of push-rods of different lengths.