Auto Repair Questions - What's Your Problem?
Mechanical rollers (left) are slightly lighter than hydraulic-roller lifters (right) and offer better performance in high-rpm applications. High dynamic loads on the hydraulic piston in the lifter will actually force it down, losing lift and duration. One thing that can help prevent this piston movement in hydraulic lifters of any kind is to use a thicker oil (like 20w50) along with a higher oil pressure. View Related Article