A "Little dab will do yah" of the zink based "Head and Shoulders" shampoo will fortify the high pressure carrying capacity of the oil so the lifters/cam don't wear.
Uh, probably not. It's possible that the zinc pyrithione in the shampoo has some EP lubricant quality. I can't find a reference anywhere that it's ever been used for that commercially, but it's possible. Of course, it's also possible that the moon is, in fact, made of green cheese and NASA scammed us so they could get a lock on the interplanetary green cheese market.
Guys, Zinc is used all kinds of places - in batteries, in vitamin pills, in oil additives, in pot metal, and, yes, in dandruff shampoo. It's just a soft metal like copper and gallium (which are on either side of it in the periodic table) and cadmium, which is below it.
Silicon (which is brittle and glassy and makes computer chips) and Silicone (which usually in greases and rubbers) are two very different things. So are batteries, pot metal fittings, lubricant additives, and shampoos. They generally don't substitute well for each other.
The "zinc" extreme pressure additive in lubricating oils is
zinc dialkyl dithio phosphate. It has attatchment points to long oil chains at four corners of the molecule, so it's very oil-soluble. It forms a large, flat molecule with a chemical affinity to electropositive metals (like iron and steel). By mass, there's much more sulfur and phosphorus in it than zinc. Zinc comes first in naming because metals always come first in molecule names...
The "zinc" in shampoo is
zinc pyrithione. It's water soluble, and would be insoluble in lubricating oil. Dump it in the sump and it'll probably head straight for the bottom. Likewise, it's missing the thiophosphate groups that make it want to stick to ferrous metals. It is, however, quite poisonous to bacteria and fungi, which is why it's used in dandruff shampoos, fungistats, and bacteriastats, and its water solubility means that it can get into their systems to kill them.
Two completely different compounds desgined for two completely different uses. They have as much in common as the sun and an ice cube, both of which are mostly hydrogen. And, like the sun and ice cubes, they don't substitute well for each other.
Leave the tribology to the professionals, please.
So what will work? If you do the total-loss lubrication system you're talking about, nearly anything oily will work as long as it's the right viscosity and is clean. For engine longevity's sake, you'll want to make sure the oil is neutral or basic (not acidic). Otherwise, pretty much anything that is in the range of 9.3 to 12.5 centiStokes at 100 C (212 F) and oily will do the job. Total loss lubrication is a special field - you don't have to worry about changes of chemistry in the crankcase(the oil isn't there long enough to have chemistry happen), but you do have to be concerned with gum formation during storage, cold viscosity, etc.
Speaking of unmodified oils, there are only a few synthetic lubricants that are as good as castor bean oil for resisting scuff and protecting metal. If all engines used total-loss lube and weren't required to be started below 20 C, we'd probably see a lot of castor oil everywhere. We have to add things like ZDDP to petroleum (and synthetic) oils to make them anywhere near as good at scuff resistance as castor oil is right out of the box. The problem, of course, is that castor bean oil thickens after high temperature exposure, forms gums, and can go acidic. So you don't want to
leave it in the crankcase. For total loss lubrication, it's the bomb.
That would be my strategy for listeroid lubrication grown on the farm: grow some castor beans, press the oil, degum it (basically, make biodiesel out of it), and thin as necessary with something light like corn or rapeseed ("canola" is redundant and lame) to get the right viscosity. And skip the dandruff shampoo...
And yes, I am a degreed chemist...but work in IT because the money is better.