What are the components of the valve train?

[VanNicole]

The valve train consists of two groups: the valve drive group and the valve group. The valve drive group includes the crankshaft timing gear, camshaft timing gear, camshaft, tappet, push rod, rocker arm, valve clearance adjustment screw and lock nut, and rocker arm shaft. The valve group includes the valve, valve guide, valve spring, valve spring seat, valve oil seal, and valve seat. Content expansion: 1. When the camshaft rotates and the base circle part of the cam contacts the tappet, the tappet does not rise, and the transmission parts above the tappet do not move, because the valve is closed. 2. When the raised part of the cam contacts the tappet, it starts to lift the tappet, thereby opening the valve. When the highest raised part of the cam contacts the tappet, the valve reaches its maximum opening. 3. Subsequently, the raised surface of the cam in contact with the tappet begins to gradually decrease, and the valve starts to close under the action of the valve spring, reversely pushing the rocker arm and other transmission components, causing the tappet to move downward to maintain contact with the cam. 4. When the raised part of the cam leaves the tappet, the valve is completely closed.