So former Shell Oil engineer Ben Visser's article in July 20 2017 General Aviation News page 12
leads to the conclusion that
a bit less than
1400 ppm of ZDDP
is optimum for wear.
But his comments on non-zinc detergents in some automotive oils burning up and leaving ash deposits that cause pre-ignition pinging also trigger some thoughts.
Which automotive rated oils have the lowest levels of ash deposits?
He was talking about using AUTOMOTIVE OILS in an AVIATION engine and why that may be a bad idea.
He goes into how the 1400 PPM level may not be RELEVANT for AUTOMOTIVE engines because they are designed and built DIFFERENT than an AVIATION engine and are not as susceptible to the problems an AVIATION engine is with high levels of ZDDP.
But hey let's take away whatever from wherever.