Being into diesel performance for several years now the cam manufacturers have been really pushing running an additive in the last year or so. They have had to replace more cams in this time than in the last 6-7 years since they have become popular. bobistheoilguy has done some testing showing the lower zinc and phosphorus levels in the CJ 4 oil. My new truck is an emissions equipped and I have to run it in it. If it wasn't I would be running john deere oil or whatever is available in CI 4.
Not sure I agree. I've been a Diesel advanced development engineer for a major Diesel OEM for 35 years. My responsibilities have included engine oil qualification and specification development fat an oem level. Consider this: Virtually no oem uses flat tappet anymore, everyone has gone to roller followers for performance and life.
As a result, there are no more high volume flat tappets produced anymore. All the stuff you get as service parts or hotrod parts is from smaller producers with old, low tech machines (repackaged and relabeled), is made in low volumes with minimal quality systems, or is offshore sourced. In the past, aftermarket tappets were relabeled parts from high volume, high quality domestic manufacturers.
I know that the oem that I worked for (till I recently retired) hasn't't made an engine with flat tappets for probably 15 years, and the switch wasn't't because the oil has degraded in that time. I think this is true with car engines (gasoline) also.
The other thing that's happened (my observation, not confirmed with data) is that it looks like the aftermarket cam grinders are pushing the envelope re valvetrain design and are pushing tappet /lobe contact stresses beyond safe levels for satisfactory life. It's easy for them to blame failures on oil composition and sell a high profit additive, which they are buying from one of a handful of additive formulators (we called the additives mouse milk) and labeling with their own brand.
What aftermarket supplier is going to tell you that the super duper high output cam he sold you is designed beyond accepted limits, but the trade-off is 3 extra horsepower?
I'm not saying definitively that you are wrong, but I do know dozens, if not hundreds of competent engine and lubricant engineers and chemists in the industry who share my views.
Alan