Who is correct regarding the operation of a flat-tappet hydraulic lifter?

A flat-tappet hydraulic lifter functions by using oil pressure to adjust for valve clearance, which allows for quieter operation and efficient engine performance. When engine oil is pumped into the lifter, it fills the internal cavity, pushing a piston against a spring inside the lifter. This action compensates for the wear and allows the tappet to maintain contact with the camshaft's profile.

Recognizing this operation, both technicians might have valid points in their descriptions of how flat-tappet hydraulic lifters work. For instance, Technician A may explain the pivotal role of oil pressure in enabling the lifter to adjust for wear, while Technician B might highlight the significance of the lifter's design in minimizing engine noise and effectively controlling valve timing.

By acknowledging the correctness of both technicians' insights, it is clear that their collective knowledge encompasses the essential aspects of flat-tappet hydraulic lifters' functionality. This reinforces the understanding that lubrication and design play critical roles in their operation, synergizing to achieve optimal engine performance.