Quote: I honestly don't know. I've heard similar rumblings that there are new extreme-pressure additives that have supplanted ZDDP in newer engine oils and the flat-tappet worry is overblown. But I just don't know. What incentive is there to include this kind of EP anti-wear chemistry in new oils? Virtually all new and recent engines have roller lifters.
The other thing to consider is the profile of the cam being run and the valve spring pressures. I honestly wouldn't worry much about things like flathead engines and tractor engines that are low-lift cams meant for low RPM, because the pressure at the cam/lifter interface is so much lower. Besides, things like Ford flathead v8s and Mopar flathead sixes and eights pre-date "advanced" oil technology anyway- they would run with straight mineral non-dispersant oil just fine so lower ZDDP in current oils is probably not a big issue.
Its a different story when you're talking about protecting a muscle-car v8 cam with higher spring pressures and aggressive lift rates.
But even there, I'm more likely to believe that the Diesel oils really do have replacement additives that might protect older engines. The trucking industry still has a LOT of very valuable older hardware out there in daily use that demands protection. Fleet operators would jump down Chevron, Mobil, and Shell's throats if the latest Delo, Delvac, and Rotella oils caused all their engines older than 1990 to eat themselves, and they're not big on carrying mixed inventories of oils for older vs. newer engines in the same fleet either.
|
