I work at Advance Auto Parts several days a week & took notice that the new shell rotella 15W-40 diesel oil now has a SM rating.
Several months ago that oil did not have the SM rating.
For those not familiar the SM rating, it means a reduction or complete elimination of the zinc additive for anti-scuffing.
This pertains to flat lifter camshafts & distributor gears to camshaft drive gears having no protection from scuffing.
Unless you use GM EOS which has a content of zinc for camshaft breakin as a suplementary additive, you will only have left pure racing oil, such as royal purple, redline or valvoiline.
As of right now till i contact shell i would use the above oils or use mobil one with GM-EOS to supply the necessary zinc for proper anti scuffing.
If anyone has more info on this devastating loss of engine protection lets hear from you.
Looks like the EPA is winning the battle.
They could care less about the older vehicles with flat lifter camshafts & distributor gears which drive the high load contact to drive the oil pump.
All the newer engines run the oil pump at the front of the crankshaft & there is on scuffing in that area. Bill
Several months ago that oil did not have the SM rating.
For those not familiar the SM rating, it means a reduction or complete elimination of the zinc additive for anti-scuffing.
This pertains to flat lifter camshafts & distributor gears to camshaft drive gears having no protection from scuffing.
Unless you use GM EOS which has a content of zinc for camshaft breakin as a suplementary additive, you will only have left pure racing oil, such as royal purple, redline or valvoiline.
As of right now till i contact shell i would use the above oils or use mobil one with GM-EOS to supply the necessary zinc for proper anti scuffing.
If anyone has more info on this devastating loss of engine protection lets hear from you.
Looks like the EPA is winning the battle.
They could care less about the older vehicles with flat lifter camshafts & distributor gears which drive the high load contact to drive the oil pump.
All the newer engines run the oil pump at the front of the crankshaft & there is on scuffing in that area. Bill