Many types of valves are on tractors including valves in the hydraulic pump, carburetor, and oil pump but when used alone the term "Valve" refers to the Intake and Exhaust Valves. These open and close based on the action and timing of the camshaft to allow air and fuel to be drawn in and burnt exhaust gases to be push out.
A hydraulic device that controls fluid flow direction, pressure, or flow rate.
(e.g. 24 valves) Signifies the total intake and exhaust valves in an engine. For example, a 24-valve V-6 would have 4 valves per cylinder: 24/6=4. A 16-valve V-8 would have 2 valves per cylinder: 16/8=2. More valves allow the engine to breathe better at high RPM and produce more power.