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 ...

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, ...

Camshaft technology is continually changing. From new lobe profiles to various forms of lobe placement, each manufacturer takes its own approach to modern performance. While flat-tappet grinds remain ...

Cars are intricate machines that rely on a series of chemical and mechanical processes to work properly. When things go wrong with one of those processes, your car can start to make some strange ...

A variety of two-stage, or discrete, variable valve lift (DVVL) and continuously variable valve lift (CVVL) systems have recently been incorporated in production vehicles. Several systems that have ...