It looks like there needs to be some expert to step up and clarify the use of lash caps.
Jerry says they press down on the keepers. Rick says they don't. It seems like both make sense.
Rick says the little hole is for
oil. Comp Cams says its to provide suction relieve when removing them. It seems like both make sense.
Comp Cams doesn't say anything about if they push on the keepers or not, but does seem to indicate it is just to help save the valve stem from wear.
If they are not pressing down on the keepers, then what good are they? It's just another piece of metal that is getting pounded by the rockers that could break. Is it stronger? Won't it fatigue just like the valve stem?
Comp Cams;
Because today’s racing engines run at higher and higher rpm levels and the cam profiles are extremely harsh, the tip of the valve stem is subjected to a tremendous amount of pounding. These engines always run just on the brink of valve float—one of the most severe conditions that can exist. The best solution to this problem is the COMP Cams® Lash Cap. These lash caps are precision machined and ground perfectly flat to maintain accuracy of valve train adjustment.They fit the valve stems well and can be removed with relative ease because of a tiny hole to relieve the suction created when removing the lash cap. The Chrysler “Hemi” engine has benefitted greatly from this design. A special version is available to accommodate the very short tip on these valves. For the ultimate in strength and reliability, you will not find a better part than the COMP Cams® Lash Cap. A must for titanium valves.