Use of Hydraulic lifters eliminates the need to regularly adjust the valve play, but can be inefficient. Solid lifters are used in performance applications.
In engineering, lifter has some unrelated meanings.
Upward-bowing of the chassis of the Lifter 4 was unexpected, due to the structural reinforcements that we added during construction.
The increased thrust is distributed evenly across the Lifter, but has a normal additive effect on the center of the Lifter that causes upward bowing in the structure.
The Lifter 4 uses slightly more current than the Lifter 3 does -- when powered by the 100kV Hvolt 100 power supply, the current draw for the Lifter 4 is between 3.5 and 4 milliamps -- for the Lifter 3 the current draw is between 2 and 3.5 milliamps.