Is there such a thing as too much zinc (presumably in the form of ZDDP) in a motor oil that will NOT be used in an engine with a catalytic converter? Some of these Lucas oils - and not motorcycle oil - ( http://www.lucasoil.com/images/medialibrary/Zinc_Values_MotorcycleOil.pdf ) have what appears to be massive amounts of the stuff, on the order of 3,100 (and even more) PPM.