There is still some 10W30 CJ-4/SM oil on the shelves. Look at the API roundel to see the service classification. Find it and stock up for the near term. Long term, you may need to find a good additive or go to a higher end oil with a bit more protection. I have used Rislone's 4405 zinc product after seeing oil analysis of it mixed into an oil I was using. Oil companies no longer list the ZDDP content on the PDS but you can find it in oil analysis (google the PQIA or Bob is the Oil Guy sites) and look for zinc around 1200 PPM. IIRC, you want to cut off before you get to 2000 PPM, as that approaches the upper limit of what's beneficial.