DWRAT,
You are either going to have to run an additive (ZDDP is one) or us one of the few oils that still has the proper amount of
Zinc/Phosphate. I run Brad Penn semi syn, it has the proper amount of additive plus a really strange green color. Some of the Valvoline Racing Oils have the right amount (not all the weights) check the internet. Comp Cams has a good writeup on what is needed.