New formula oil for a Sherman engine

[maple_leaf_eh]

Rec'd from the originator:

"Thanks Terry, We are scared of these sterling silver bearings. Oil in the 40’s was paraffin based and not all the additives. Zinc was the lubricant they used for the cam bearings. Lead in the fuel was the valve lubricant. We hate to hurt this engine with the wrong oil……………..manual just says SAE 50 over 32 degrees………….SAE 30 above zero degrees.

I am afraid it might not be a question that most researchers would need to know so unless you are trying to pour modern oil in a 70 year old “ high performance” motor from the army you would not care. You are the only guy to replay with any help. If the current oil attacks the sterling silver bearings while just sitting as theorized, we need a solution if we plan to keep these running very long in the future. Thanks for your help. Russ Morgan Loveland Colorado."