Picked this up off Chilly's board & thought it interesting. I have not actually verified it with an oil chemist, or anything like that, so consider at your own risk. But, since we've discussed it in the past, here ya go.

So far as I know, any "EP" (extreme pressure) rated lubricant/grease has to have moly compounds, not ZDDP. When breaking in cams, I used to use EP grease on them along with EOS, but switched to Crane (usually) moly-based sauce/EOS, once the cam companies started getting peevish about warranty issues. I've actually never had a cam go flat upon break-in...knock on wood, maybe 150 at this point , not counting rollers...but I'm morbidly certain it's-a gonna happen sooner or later.


"The main use of ZDDP is in anti-wear additives to lubricants (eg. greases, motor oils). To date it is the dominant anti-wear agent, present in most machine and motor oils in amount of about 1%. However for motor oil applications the amount of ZDDP has to be minimized, as the zinc and phosphorus emissions damage catalytic converters, .

The mechanism of function of ZDDP lies in chemical reaction with the surface of the metal gears under high pressure and temperature. Pressure concentrates on small unevennesses on the surfaces in contact; pressure and temperature at these points sharply rises. At such conditions, ZDDP decomposes and forms a layer of iron phosphate or iron sulfate, effectively chemically polishing the surfaces. The zinc polyphosphates and polythiophosphates also form a thin layer of glass that becomes fluid at 230 °C, further lubricating the surfaces. If higher local temperatures are desired, molybdenum compounds are used. [3]

ZDDP also has anticorrosive and antioxidant properties."


Dunno the original source, it was linked about 200 times (or so).