A valve timing system, which is used in compression release brakes in internal combustion engines, basically comprising - at least one solenoid valve, - at least one main oil line through which oil is pumped, - at least one outlet channel, - at least one upper channel, - at least one inlet channel to which the solenoid valve is mounted and to which oil is delivered from the main oil line, - at least one first piston located within the inlet channel, - at least one first spring which is located within the inlet channel and to which the first piston exerts pressure, - at least one safety valve which is located at the end of the inlet channel; and - at least one second channel to which the open end of the safety valve is connected, - at least one second piston which moves within the second channel, - at least one second spring to which the second piston exerts pressure, - at least one body into which the second channel fits and in which the second piston and the second spring are located, - at least one cavity located on the body surfaces, - an opening in the structure of the second piston, - at least one third channel, by which the cavity located on the body surface opens outwards from the body, - at least one first main piston to which the end of the third channel that does not fit into the cavity opens out, - at least one first cam which operates in connection with the first main piston, - at least one fourth channel, by which the other cavity located on the body surface opens outwards from the body, - at least one second main piston to which the end of the fourth channel that does not fit into the cavity opens out, - at least one second cam which operates in connection with the second main piston, - at least one fifth channel which opens outwards from the surface of the body, - at least one sixth channel which branches out from the fifth channel, - at least one check valve which is located on the sixth channel, - at least one valve mechanism which is located after the check valve and to which the sixth channel opens out, - at least one cylinder which is located at the end of the fifth channel that is not connected to the body, - at least one pushing piston which is located in the cylinder, - at least one valve assembly to which the end of the pushing piston opens out, - at least one pin which is located between the valve assembly and the valve mechanism, - valves constituting the valve assembly, - valve springs which enable opening and closing of the valves. - at least one solenoid valve, - at least one main oil line through which oil is pumped, - at least one outlet channel, - at least one upper channel, - at least one inlet channel to which the solenoid valve is mounted and to which oil is delivered from the main oil line, - at least one first piston located within the inlet channel, - at least one first spring which is located within the inlet channel and to which the first piston exerts pressure, - at least one safety valve which is located at the end of the inlet channel; and - at least one second channel to which the open end of the safety valve is connected, - at least one second piston which moves within the second channel, - at least one second spring to which the second piston exerts pressure, - at least one body into which the second channel fits and in which the second piston and the second spring are located, - at least one cavity located on the body surfaces, - an opening in the structure of the second piston, - at least one third channel, by which the cavity located on the body surface opens outwards from the body, - at least one first main piston to which the end of the third channel that does not fit into the cavity opens out, - at least one first cam which operates in connection with the first main piston, - at least one fourth channel, by which the other cavity located on the body surface opens outwards from the body, - at least one second main piston to which the end of the fourth channel that does not fit into the cavity opens out, - at least one second cam which operates in connection with the second main piston, - at least one fifth channel which opens outwards from the surface of the body, - at least one sixth channel which branches out from the fifth channel, - at least one check valve which is located on the sixth channel, - at least one valve mechanism which is located after the check valve and to which the sixth channel opens out, - at least one cylinder which is located at the end of the fifth channel that is not connected to the body, - at least one pushing piston which is located in the cylinder, - at least one valve assembly to which the end of the pushing piston opens out, - at least one pin which is located between the valve assembly and the valve mechanism, - valves constituting the valve assembly, - valve springs which enable opening and closing of the valves.