What Components Make Up the Engine Valve Train?
2 Answers
The engine valve train can be divided into two main parts: the valve group and the valve drive group. 1. Valve Group: This includes the valves and related components. The composition of the valve group is generally independent of the type of valve train. 2. Valve Drive Group: This consists of all components from the timing gear to those that actuate the valves. The valve drive group mainly includes the camshaft timing gear, tappets, push rods, rocker arms, and rocker arm shafts. The function of the valve train is to open and close the intake and exhaust valves of each cylinder in accordance with the engine's working cycle and firing order, allowing the air-fuel mixture or fresh air to enter the engine cylinders in a timely manner while ensuring the prompt expulsion of exhaust gases after combustion.
With years of experience in auto repair, I can say the valve train is the core component of an engine, ensuring the valves open and close on time to control air intake and exhaust. It mainly consists of the camshaft, whose lobes push the valves into motion as it rotates. Valves are divided into intake and exhaust types, responsible for opening and closing the passages. The springs apply force to keep the valves tightly closed. In pushrod engine designs, additional components like lifters, pushrods, and rocker arms are included to transmit motion forces. The timing system, such as belts, chains, or gears, synchronizes the camshaft and crankshaft movements to ensure coordination between pistons and valves. If these parts malfunction—like camshaft wear or spring fatigue—the engine may produce noise, vibration, or fail to start. Regular maintenance should include checking the timing belt replacement cycle to prevent breakage and engine damage. During repairs, cleaning carbon buildup is also crucial to maintain smooth component operation.
