The Detroit 60 12.7L pre-egr reman crate engine I put in a new 2013 semi truck now has 1,018,260 miles on it. It started out at 0 miles with CJ-4, but switched to CK-4 a few years ago when it came out. No additional additives thrown in by me from day one. Just the motor oil. Even with I have taken it over 1 million miles, it still only uses about 1 qt of oil in 11-12,000 miles, and that was before I recently replaced a valve cover gasket and rear main seal (as a preventative measure) when I had a new clutch put in. Since those repairs, I am at 19,340 miles into this interval on the oil, and it is just now slightly below the full mark on the dipstick. I likely will not have to add any makeup oil during this OCI. And the UOA's show similar numbers as when it had only 50,000 miles on the motor. CK-4 is not inferior to CJ-4 by any stretch. There are differing formulations between CJ-4 and CK-4 and Zinc as a friction reducer is not the only game in town.