Something I learned from the Motor Oil Geek on YT…..
Can’t look at ZDDP levels in a vacuum. Detergents like Calcium are antagonistic and reduce the effectiveness of the Zinc.
Modern diesel oils due tend to have high ZDDP levels but also tend to have much higher detergent levels. His recommendation for older flat tappet engines is something more like VR1. High ZDDP but low detergent package.
I’m switching my truck over to VR1. It’s really not terribly expensive.
