Zinc oil additives

The whole reason detergents were added, IMO was because people either would not change their oil, ir did it way less frequently than they should. I think you could run the old single weight non detergent oil as long as there was sufficient ZDDP for the type of lifter you run. That's my opinion and I'm stickin to it.

They use detergents and dispersants (among other things) because no engine has ever run on “new” oil. All engines run on used oil unless you change it every 15 minutes of run time.