OK, may I show my lack of understanding? I have been using HD oil in my gasoline engines for decades. The oils were rated for either "C"ompression or "S"park service. Our gubermint regulators have changed the rools such that the refiners/marketers of the oil have had to change their litsting of applications due to the gubmint's regulators ideas of what is good for us. So engines that I have exposed to the good ole oils that have served so well are now supposed to be exposed to oils similar to the "meh" formulation of oils that I have passed by before. The concern seems to be for my catalytic converters that have suffered through so many years of exposure to the good stuff in my old oils and should now, according to the gubmint regulators, be preserved by using oils with less of the good stuff. Same vehicles, same cats, but now different, maybe less protective oils. Hmmmmm.
If my cats are already dead, will the new spark rated HD oil change that? The potential damage to the cats from 150,00 mils of the good ole oil, is that of the nature that the cats are now less efficient in reducing hydrocarbons or is the type of damage that restricts my exhaust system, or both???
