AeroShell has set the standard for aviation oil. These ashless dispersant oils were specifically developed for aviation piston engines. They combine non-metallic additives with selected high viscosity index base oils to give exceptional stability, dispersancy and anti-foaming performance. Case of 12 one quart bottles.
No general rule exists for every engine type when choosing the correct grade of oil; however, based on the average ambient outside temperature at engine start-up the most common grades are SAE 40 and SAE 50, which equates to AeroShell Oil W80 and W100 respectively.
Traditionally, the choice is associated with climatic zones:
AeroShell W80 for cold climate regions (-17 - 21°C)
AeroShell Oil W100 for temperate regions (15 - 30°C)