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 ...
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 ...
COMP Cams Explains the Pros and Cons of Solid, Hydraulic, Flat-Tappet, and Roller Cams, and the Advanced Technology that makes them all Work. With horsepower seemingly growing on trees these days, ...