You have a roller wheel, rolling along the lobe, the majority of the load is actually on the needle rollers in the lifter, all the wheel has to do is roll up and down the lobe. That is, until peices of that lobe, begin to flake off in chunks, as seen in the previous photo. No amount of oil on the surface is gonna prevent a whole chunk of metal from separating UNDER the wear surface. (Base casting of metal) Its NOT a heat issue, there is less friction, therefore heat, with a roller versus a flat tappet, otherwise flat tappet cams would just RIP layers of metal off in the same fashion. Put a quality cam in it, the engine will run 300k miles. With the same oiling "flaws" think about it
