What is the function of hydraulic valve tappets in some engines?

Hydraulic valve tappets play a crucial role in the efficiency and maintenance of some engine designs, particularly in eliminating the need for constant valve adjustments. These tappets automatically adjust to the variations in engine temperature, wear, and pressure, ensuring that there is always the appropriate amount of clearance between the valve and the rocker arm. This automatic adjustment feature significantly reduces the frequency of manual checks and adjustments that would otherwise be necessary to maintain optimal engine performance.

By keeping the valve clearance consistent, hydraulic tappets also help improve the reliability and longevity of the engine. This functionality means that the engine can maintain more stable performance over time, as there is no gradual increase in clearance that might lead to inefficiencies or additional wear. The result is a system where the complexity and labor involved in regular maintenance are minimized, leading to a more user-friendly experience for vehicle owners and mechanics alike.