OK. From that perspective, I'd want the plungers adjusted near--but not at--the bottom of their travel.it's more the question of why they tend to want to be noisier at startup with different preloads if that makes sense.
That way, as the lifter plunger bleeds down from valve spring pressure, it can't go very far before it's at the bottom of it's range. And being adjusted near the bottom of it's travel, it'd take minimal oil to pump it back up again when the engine is started.
Adjust the preload too tightly, the plunger is at the bottom of it's travel, and the valve can't shut. Engine runs terrible, or maybe not at all.
The lifter plunger has a limited movement within the lifter body. At the top, it runs into the snap-ring, and it can only go down so far before the check-valve hits the inside of the lifter body. So again, some lifter plungers have extremely limited range of motion, and others have heaps and bags of travel.what do you mean travel?