Amsoil claim: ash limits for API SM / ILSAC GF-4

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Saw the following in this Amsoil PDF:

Quote:
In recent years, API and ILSAC have reduced the ash content in engine oil to below 0.80% (max) by weight to meet API SM, ILSAC GF-4 specifications. Because all SAE xW-20 engine oils are required to have low ash, there is less tendency for carbon formation when they are burned in the combustion chamber.


I'd love for this to be true, but I haven't found evidence for it yet. For example, Infineum's summary of API and ILSAC specs makes no mention of sulfated ash for SM/GF-4, SN/GF-5, etc.

Was this statement an error on Amsoil's part, or am I missing something?
 
I would wonder if Amsoil is hyping the new additive package reformulations they are purchasing.
 
I see that SN-RC directly specifies phosphorus and sulfur content...0.06-0.08% P and 0.5% max S for 0/5WXX.
Looks like there are similar limits for SM.
 
Unless the periodic table has changed, metal sulfates aren't "carbon". It appears Amsoil does not know what it is talking about.

Charlie
 
Originally Posted By: Virtus_Probi
I see that SN-RC directly specifies phosphorus and sulfur content...0.06-0.08% P and 0.5% max S for 0/5WXX.
Looks like there are similar limits for SM.

Sulfated ash is different from P and S, though they're all part of SAPS.

Thinking about it now, maybe whoever wrote that Amsoil doc made that same mistake. That'd be an awfully junior-grade mistake for an oil blender, but weirder stuff has happened....
 
Originally Posted By: d00df00d
Originally Posted By: Virtus_Probi
I see that SN-RC directly specifies phosphorus and sulfur content...0.06-0.08% P and 0.5% max S for 0/5WXX.
Looks like there are similar limits for SM.

Sulfated ash is different from P and S, though they're all part of SAPS.

Thinking about it now, maybe whoever wrote that Amsoil doc made that same mistake. That'd be an awfully junior-grade mistake for an oil blender, but weirder stuff has happened....


This has always confused me, seems like ash is often used as a synonym for SAPS and even XOM refers to the Sulfated Ash level of their oils when I'm pretty sure that they mean SAPS. Anyway, I thought info I gave might be germane to the discussion...like you, I don't see any specific reference to SAPS in SN or its cousins.
 
For ASTM D6335, the total deposit formation was cut by 15 mg. from the SL to SM transition and the ASTM D7097 deposit formation value was cut almost in half.

From the 2009 Amsoil TSB linked above:

Quote:
CARBON DEPOSITS:
As noted in the Mazda bulletin, carbon formation in the RENESIS
engine can lead to engine misfire and knocking. Carbon
deposit formation may not be due to the type of base oil, but
can also be related to the ash content of the oil additive package.
Higher ash content oils can form more carbon deposits
than lower ash content oils.

In recent years, API and ILSAC have reduced the ash content
in engine oil to below 0.80% (max) by weight to meet API
SM, ILSAC GF-4 specifications. Because all SAE xW-20
engine oils are required to have low ash, there is less tendency
for carbon formation when they are burned in the combustion
chamber.


The TSB never said anything about Sulfated Ash.

Any type of ash deposit can mix with the oil and further contribute to oil degradation.
 
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In Analytical Chemistry there are two forms of ash residue:

The residues after a sample is completely burnt consists mostly of metal oxides.

The ash remaining after incomplete combustion could contain any number of chemical species, including inorganic and organic.
 
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Thanks for the clarification and elaboration, MolaKule!

Are you suggesting that the deposit formation specs for SM/GF-4 provide a way to get to that 0.8% figure? When I found that Infineum doc, I just searched for the word "ash" and only found it in the diesel specs.
 
Ash, in general chemistry terms, is the residue of complete or incomplete combustion and contains mostly solids.

Quote:
The ash remaining after incomplete combustion could contain any number of chemical species, including inorganic and organic.


This can include carbonaceous residues.
 
Here was the kicker for me:

Quote:
Mazda Engineering did state that “not all synthetic oil is at a disadvantage in terms of carbon buildup, but use of untested, non-genuine oil should be avoided.”


I.e., use only XXX from the dealer; Hmmm, where have we heard that before?
 
Originally Posted By: d00df00d
Thanks for the clarification and elaboration, MolaKule!

Are you suggesting that the deposit formation specs for SM/GF-4 provide a way to get to that 0.8% figure? When I found that Infineum doc, I just searched for the word "ash" and only found it in the diesel specs.


Amsoil, IMO, should have stated what the basis of their 0.8% figure was referenced to. I think (not sure) they meant relative to the transition from SJ/SL to SM GF-4, considering the time frame in which it was written.
confused2.gif


Either way, I agree that it was poorly written and certainly not written by an analytical or physical chemist.
shocked2.gif
 
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Originally Posted By: Virtus_Probi
This has always confused me, seems like ash is often used as a synonym for SAPS and even XOM refers to the Sulfated Ash level of their oils when I'm pretty sure that they mean SAPS. Anyway, I thought info I gave might be germane to the discussion...like you, I don't see any specific reference to SAPS in SN or its cousins.

SA has a specific definition and is a component of certain HDEO specifications. For instance, you'll find E7, E9 lubricants having SA of 1 or less, because the specification combination requires that.

SAPS levels seem to be treated a little differently as to what's called/marketed as high/mid/low when it comes to ACEA specs for passenger vehicles versus the commercial side. I don't think it's quantifiable in the same way as SA with simply one number.
 
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