valve lifter

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Last updated

July 14, 2026

Quick Summary

A valve lifter, also known as a tappet or follower, is a component in internal-combustion engines that opens the cylinder's valves. It rides on the cam lobe of the camshaft, transferring the cam's motion to the rest of the valve train.12

There are two main types of valve lifters:
* Mechanical lifters: These require periodic adjustment to maintain a small gap, known as valve lash, between the lifter and the valve stem. This ensures proper valve closure.32
* Hydraulic lifters: These contain an oil-filled chamber that automatically compensates for any clearance, eliminating the need for manual adjustment and reducing noise.32

Valve lifters are crucial for synchronizing valve operation with piston movement, ensuring the precise timing of air-fuel mixture intake and exhaust gas expulsion necessary for an engine to run smoothly.2

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gasoline engine
Valves, pushrods, and rocker arms
…be eliminated with entirely mechanical valve-lifter linkage only if the tappet clearance between the rocker arms and the valve stems is closely maintained at the specified value for the engine as measured with a thickness gauge. Hydraulic valve lifters, now commonly used on automobile engines, eliminate the need for periodic…
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…be eliminated with entirely mechanical valve-lifter linkage only if the tappet clearance between the rocker arms and the valve stems is closely maintained at the specified value for the engine as measured with a thickness gauge. Hydraulic valve lifters, now commonly used on automobile engines, eliminate the need for periodic…
Read More