The rules in some racing classes restrict competitors to running hydraulic valve lifters. Cheaters have been known to run hydraulic lifters on a mechanical (solid) cam profile. Solid cam profiles ...

From the archives: The beauty of hydraulic lifters is that they self-compensate for valvetrain clearances, doing away with the need for valvetrain adjustment. To celebrate HOT ROD's 75th anniversary, ...

The engines of yesteryear were pretty simple, with tappets clackity-clacking away on cam lobes, opening valves, and making a ruckus while doing it. Mechanical lifters were adequate for valve operation ...