[Walt Fricke]

Well, I see why you wondered about this. So far, no one who has removed rocker arms has said this play is an issue. And, in particular, the guys who do this kind of thing for a living. For the life of me I can't see how it matters. There is play inside the cup, and oil. When the cam is on the base circle, the rocker foot may, indeed, be on the cam, but the oil barrier inside the cup provides the clearance - it isn't like that oil will hydraulically lock things, removing the clearance.

Too little clearance runs the risk of a valve not fully closing - a bad thing. My one experience with hot valve clearance is that it opens, and hence is an additional safety feature. But I'm not about to set at zero clearance based on that theory.

So why anyone would go to the trouble of doing this closing (is that a flat side of the tool just pressing the cup lip inward?) up the gap on the cup baffles me.