Abstract: An easily assembled valve shifting mechanism includes a hexagonal shaft over which several different cam plates are slidably assembled in a predetermined manner. Each cam plate includes complementary cam surfaces for engaging and providing positive motion to a cam follower mounted on a valve spool. The cam surfaces of all the cam plates bear a predetermined relationship to each other to cause movement of the different valve spools in a predetermined sequence. One of the cam plates further includes detent means for defining each of the steps in the predetermined sequence.