Lingo

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Can someone direct me to info that explains what SF,SG,SJ,SL,SM etc. means. Is there certain add packs in oils or is it the year produced? Thanks
 
So you are saying that a SM oil is better than say a SF,SG,SL oil then? Meaning the add pack is better?
 
Now that is a hotly debated subject. For instance SL had higher phosphorous and zinc. SM lowered the Phosphorous limit to 800 PPM to aid emission system life expectancy.

Obviously some will argue that SL with higher levels of zinc and phosphorous is better then SM from an engine wear/lubricant life stand point. SM oils are very well proven at this point and SN will be here soon enough. Then we can all debate whether SM is better then SN.
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When SM came out, it limited ZDDP on 20 and 30 (NOT 40) weight oils to protect O2 and Cats. So, many see SL with more ZDDP as being better. In reality, a 40 weight SM oil can have those levels, too.
 
ridge - It seems that you catch on fast.
Just one thing - it is highly loaded flat tappets that are in danger with the latest 5-20 and 5-30 gov't castrated oils.
Many overhead cam engines are flat tappet/follower/lifter types ,and are so lightly stressed that the newest oil is perfectly fine with them.
 
"gov't castrated oils."

It wasn't the government that wanted the limit, it was input from auto manufacturers over warranty concerns.
 
Most evolutions are cooperatives. Cats required alteration to the nation's fuel distribution system ..etc..etc. There were certain advantages to extending the OEM warranty on emissions components. At one point in the distant past, MB got a pass on higher gms/mile (in a diesel, iirc) for extending their warranty to 100k vs. the 80k of the time.

I imagine that the OEM's were being hammered to manage 150k of life expectancy (already doable), but needed some aged in the field R&D before the introduction/adoption.

An engineer at work would write proposals for increased capacity on our evaporators. First, he assured that he had the increased capacity in the bag before he offered it for justification for the expenditure.
 
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