Found part of the problem (pic) :D

Thru the decades we replaced dozens of wiped cams,, I did it as an apprentice, at the dealership without choice,, and after the first few dozen,, and becoming a ticketed tech, con't to do so,, as tearing the engine down, was not a practical alternative, and had already proven (to me) unnecessary,

I serviced these same vehicles for years/decades after,, and I don't remember a single one coming back for anything related..

FWIW... hope it helps