[Mart]

A piece of advice re adjustable lifters. You can see clearly in the illustration above, what is done to make the threads tight in the threaded hole in the lifter.

If both parts parts of the thread are not fully engaged in the lifter then it will be loose. The length of thread in the French (I know yours aren't french, but I'm just trying to illustrate what I'm saying) Lifter is only so long. Too far in and it will be loose, too far out and it will be loose. There is a finite range of stickout where the lifter will be nice and tight. Stray either side and it will be loose and will not work.

If you are confident the amount of stickout is in the sweet spot, giving the screw a good squeeze like in the illustration might be all it needs.

Mart.