Sunday, Nov 29, 2009 at 14:15
After API SG rating oil, things have changed slightly.
We are up to SM rating now.
Oils have been produced with less anti wear additives ( mainly zinc & phosphorous) to comply with the latest exhaust emission regulations.
SG oil contained roughly 1301ppm Phosphorus and 1280 ppm Zinc
SM oil contains roughly 770 ppm Phosphorous and 939 ppm Zinc
So the main antiwear additives have been substantially reduced.
No matter what brand of oil you use, the ratings are the same so the
oil you used six years ago or so is completely different to the same type & brand
that you put in your engine today.
Oils ain't oils Sol :)
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