Camshaft law requires the crown of the flat tappet to run properly on a wide contact pattern, while the crown of the tappet base and the taper of the cam lobe forces the tappet to spin in its bore to eliminate wear.

When all of this is operating properly, tappet and/or cam wear is held to a minimum. However, in recent years, cast-iron tappets and cam wear reached new heights. Engine builder Brian Tilburg of Tilburg’s Racing Engines explains that, “It’s almost like playing Russian Roulette. You just never know when a cast-iron lifter is going to break and eat the cam.” But using a proven grade of break-in oil and Trend’s new tool steel lifters on a cast-iron camshaft seems to cure the problem. Trend Performance tells us their new tool steel lifters can last four to five times longer than the old cast-iron style and in addition, they can be re-ground if necessary.