Copied from:
http://www.lnengineering.com/oil.html#Z5
Clearly, the new CJ-4 has less wear additives than the CI-4, by 25-30%
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What motor oils had the 0.12% levels of
zinc and phosphorus recommended?
The current API standard is SM, and calls for 0.06-0.08% Zn and P.
Here are the running averages for all the oils tested thus far, listed by their API rating:
API P (ppm) Zn (ppm)
SE-SJ 1301 1280
CI-4 1150 1374
SL 994 1182
CJ-4 819 1014
SM 770 939
I do not recommend the use of any SM or CJ-4 motor oils in any aircooled Porsche, or any vehicle that can benefit from the added anti-wear additives such as pre-ODBII vehicles. If your vehicle is designed to use these newer oils or if your vehicle requires a manufacturer approved
oil and is still under warranty, always follow your manufacturer's recommendations!