I have wondered for a long time.
On solid lifters, the lash is set to X thousandths on the back side of the cam lobe. That is easy to visualize.
On hydrolic lifters, there are a myriad of wives tales on setting, several different techniques for setting, either torque, or back side lash.
Perhaps it is my misunderstanding on how a lifter works, especialy hydrolic.
My presumption is, the oil in the lifter acts also as a non compression medium that affects lash. If the spring in the lifter is the only real resistance, aside from the physical solidity of both the base, and spring compression, then several other factors come into play.
With the rockers I have chosen to install, the directions call for setting the rocker on the backside of the lobe, and tightening untill the pushrod stops turning. What is stopped turning, and how much torque is the test?
It may sound overcomplicated, but, it is hard to describe mechanical actions without pictorial perspectives.
After eliminating twist, then turn 1/4 to 1/2 turn and it is set.
Hokay.
Does this eliminate the pressure the oil in the lifter creates? Is the lack of twist, an easy twist, or a twist under pressure?
I understand the lifter is a pump that charges the pushrod to lubricate the rocker assembly, and ultimately lubricate the cam lobes through drip off.
I understand, tightening to eliminate clack on hydrolic lifters. A slight clack is good for mechanical rockers. It gives the valve time on the seat to moderate temperature.
With hydrolic lifters I am in the dark.
Why is the rocker set this way?