921 forces spool 140 to move left the right portion 920 of the spool valve 140 stops fluid flow at the retard end 910 but simultaneously the left portion 919 moves further right leaving advance portion 98 in fluid communication with duct 99 because of the inherent torque reversals in camshaft drained fluid from the advance chamber 92 feeds the same into retard chamber 93 via one way valve 97 and duct 95 as can be appreciated with the cta cam phaser the inherent cam torque energy is used as the motive force to re circulate oil between the chambers 92 93 in the phaser this varying cam torque arises from alternately compressing then releasing each valve spring as the camshaft rotates it should be noted that fig4 and 5 are used to show different types of vct system suitable for the present invention some structures are not depicted in detail for these details refer to fig2 u2013 3 the following are terms and concepts relating to the present invention it is noted the hydraulic fluid or fluid referred to supra are actuating fluids actuating fluid is the fluid which moves the vanes in a vane phaser typically the actuating fluid includes engine oil but could be separate hydraulic fluid the vct system of the present invention may be a cam torque actuated cta vct system in which a vct system that uses torque reversals in camshaft caused by the forces of opening and closing engine valves to move the vane the control valve in a cta system allows fluid flow from advance chamber to retard chamber allowing vane to move or stops flow locking vane in position.