The reduced level of ZDDP was the EXCUSE given by the cam 'n' lifter suppliers, to COVER UP their outsourcing of their flat-tappet product lines to the low bidder.
Guess who.
The Communist Chinese could screw up ANYTHING. So they sent shiploads of lifters to us that were too soft, or otherwise defective, and of course the Communist Collaborators in this country did nothing for Quality Assurance inspections because that would cost money.
Since DEFECTIVE PRODUCT would be covered by "manufacturer's (actually the reseller's) warranty", various "Cam companies" blamed ZDDP and the EPA for what was really a junk lifter and perhaps a junk cam core problem. Then they look like heroes for actually supplying a warranty replacement cam and lifter set; or they have a reason to deny warranty in some cases.
Yes, the EPA did require lower levels of ZDDP in most motor oil, due to "poisoning" the catalytic converter. (How much oil does an engine have to burn for the ZDDP to affect the catalyst?) So the EPA became a convenient scapegoat for the Junk Lifter (and perhaps Junk Cam Core) Plague.
I'm not saying that junk cam cores never happened before the Communists got involved. Chevy had notorious cam failures in the late-'70s, early '80s. Thank God for "secret warranties" where the vehicles weren't recalled like they should have been, you only got "assistance" if you showed up at a GM dealership and bittched.
Corporate America has never been big on ethics...
