My Info from a lot of reading about aviation oil !
With Aeroshell full synthetic oil (the first on the market) the Lycomings & Continentals engines were rapidly destroyed. The oil was removed from the market !!
All Aero oils are now teil-synthetish or mineral !
The problem was that the full synthetic oil could not cope with the lead & its combustion products ! They are not sollubile in the full synthetic oil. The combustion Reste & Ablagerung killed Lager Laufbuchsen & Ventilen.
For our cars now with non leaded fuels this is not a problem ,
Sorry to write in english but for Deutsch I need assistance !
MM