As I've monitored the zddp levels in Rotella for many years, the "CI-4" version had close to 1500ppm of zddp. CJ-4 went down to about 1300ppm zddp, with the latest version CK-4 being a bit less for the 15W-40 oils. Valvoline "Super Blue" tended to be similar, as I recall. Seems like the detergency additive package was improved with the CJ-4 version, as they had a stained oil pan they'd soaked one end of in the then-new CJ-4, showing how clean the new formulation got the stained pan clean on the inside. Never seen anything like that before. The 5W-40 syn oils usually have about 100ppm less zddp than the non-syn 15W-40 oils, but the syn basestocks probably make up the difference, I suspect.
Considering the "dirty" environment that diesel oil works in (sooty blowby, fuel dilution, etc.), I would suspect the diesel-rated oil has a better detergency additive package than a gas-rated oil, which should be good, from what I can determine. Never did quite understand the loophole that allowed the recent dual ratings (gas and diesel) of a diesel-designed oil, but if the oil works in both environments, then it being in a gas engine should be an easy task for it. Where things got flaky was in the newer gas engine emissions situation, with some ratings related to emissions hardware longevity. Which zddp and other items in the mix might have some issues with. BUT as most of our older engines are not in that emissions regulations situation, no reason to NOT use it even if the "car" designations are no longer on the container or in the literature.
Now, in recent history, a NASCAR associate started to make his own motor oils, resulting in a full line of motor oil. From a race oil with 3000ppm of zddp to normal high-zddp oils for older cars with flat tappet cams to low-calcium blends for new cars. This owner's "oil guru" is a former NASCAR racer, I believe, who now purports against using diesel-rated oils in gas engines. Now claims the diesels use a different type of zddp than the gas engine oil needs? First I'd heard of that! Always a bit suspicious when a seller claims another brand is bad and theirs' is good, whether motor oil or creatine supplements. At least suspicious until Google leads me to the answer, one way or another.
Just some thoughts and observations,
CBODY67
Considering the "dirty" environment that diesel oil works in (sooty blowby, fuel dilution, etc.), I would suspect the diesel-rated oil has a better detergency additive package than a gas-rated oil, which should be good, from what I can determine. Never did quite understand the loophole that allowed the recent dual ratings (gas and diesel) of a diesel-designed oil, but if the oil works in both environments, then it being in a gas engine should be an easy task for it. Where things got flaky was in the newer gas engine emissions situation, with some ratings related to emissions hardware longevity. Which zddp and other items in the mix might have some issues with. BUT as most of our older engines are not in that emissions regulations situation, no reason to NOT use it even if the "car" designations are no longer on the container or in the literature.
Now, in recent history, a NASCAR associate started to make his own motor oils, resulting in a full line of motor oil. From a race oil with 3000ppm of zddp to normal high-zddp oils for older cars with flat tappet cams to low-calcium blends for new cars. This owner's "oil guru" is a former NASCAR racer, I believe, who now purports against using diesel-rated oils in gas engines. Now claims the diesels use a different type of zddp than the gas engine oil needs? First I'd heard of that! Always a bit suspicious when a seller claims another brand is bad and theirs' is good, whether motor oil or creatine supplements. At least suspicious until Google leads me to the answer, one way or another.
Just some thoughts and observations,
CBODY67
