Hi, all !
I have learned recently the EPA has decreed the zinc content of auto motor oils must go...due to the poisoning of cat. elements ( ye ol' lead in gasoline argument, remember?). This zinc compound ( zinc di-something) is an EP (extreme pressure) additive ; without it, aftermarket cam grinders are noting scuffing and scoring of lifter/ cam lobe interfaces...they are "upset"!
Have you noticed the oil ads on TV, lately? They no longer tout "anti-friction" qualities...but have emphasized "cleaning abilities". Like...Clean engines dying early is preferable to "dirty" old-timers, yes?
There IS a way out of this dilemma...buy fleet oil. NAPA sells their own brand of fleet ( truck) oils ... cheaper than the brand-name stuff; I use their 15W40 stuff.I don't worry about the tiny "0 W 0" MPG benefits...the price ain't too bad, either. Other generic brands are out there, I'm sure.
Also, the price of GM's EOS (engine assembly lube) has tripled lately! Any connection? EOS , formerly Engine Oil Supplement ( now changed just prior to the feds cracking down on the wild claims of the oil additive folks) , is laced with this zinc-based compound. Hmmm....
I'm sure Google knows about these moves ... check it out. Spread the word?
-whitevette