Zinc

I think it would be interesting to learn the actual chemical process behind some of this stuff, but I chose a route other than chemical engineering and am too lazy to learn much new :)

I am somewhat paranoid, perhaps for no real reason, of putting additives in the oil since I make the assumption (maybe a bad one) that the chemists at the oil companies put their blends together for a reason. Throwing in an additive may affect that blend.

I suspect there is more going on with the oil and camshaft interaction than just the phosphorous and zinc content, but I haven't done any independent research to look at this.

We do use zinc in one of the systems at work and I do know zinc has chemical properties similar to cobalt and will replace cobalt in the steel structure. Phosphorous is the lubricant, so maybe zinc forms a sacrificial layer in the steel that is continually replaced by the zinc in the fluid.