Technician A says that excessive hydraulic lifter pump-up can occur if the valves float. Technician B says that hydraulic lifter valve adjustment on most engines positions the plunger at its center of travel in the lifter body. Who is right?

Question

Technician ​A says that excessive hydraulic lifter pump-up can occur if the valves float. Technician B says that hydraulic lifter valve adjustment on most engines positions the plunger at its center of travel in the lifter body. Who is right?

Quizplus · Accepted Answer

Technician B is correct because the standard procedure for adjusting hydraulic lifters is to position the plunger in the middle of its travel to ensure proper operation across the engine's operating range. Technician A's statement is incorrect because valve float is a condition that occurs when the valve fails to follow the cam profile due to the valve spring not being able to keep the valve in contact with the cam at high RPMs, which is unrelated to hydraulic lifter pump-up.

Technician ​A Says That Excessive Hydraulic Lifter Pump-Up Can Occur

Technician A Says That Excessive Hydraulic Lifter Pump-Up Can Occur