Whats the best oil to use for 1931 Knight engine?

Duh... You gotta use Royal Purple.

 

Stp

 

I'm not sure on what oil to use, but my granpa always said them Willis (like bruce willis) Knights weren't runnin' if they weren't smokin'......

 

The more oil a motor burns, the more often it needs to be drained, to get rid of as much of the by-products as possible. Otherwise they build up and are recirculated throughout the system, which increases wear.