HPL PCMO 5/30 (Base) VOA

[Sandstorm]

I do understand that many elements which show up have multiple forms ("zinc" for example has many forms such as ZDDP, etc)

But I do have to wonder why so much sulfur??? Generally that is corrosive when it is combined with moisture (sulfuric acid), and also VERY detrimental to catalytic converters. (Hence ultra low sulfur fuels ...)

So is that sulfur in some form that otherwise does little harm because it's some variant of "normal" sulphur?
And is that why the TBN is so incredibly high; to offset the anticipated sulfuric acid from extended OCI?

I was thinking the same thing. How can this be a good thing? As you said, sulfuric acid is no bueno...

 

[MolaKule]

So for us less “chemistry-educated”, is the amount of sulphur in the samples considered excessive, or is this something that is average in pretty much most motor oils? All I see is visions of sulfuric acid eating away at my seals!

Good question!

Sulfur levels are rarely shown because for a sulfur reading, it usually costs extra so when you DO see sulfur levels, many are surprised.

That sulfur level is not unexpected for an analyst since the sulfur level will vary depending on the type of compounds incorporated into the additive package.

One also has to be aware that various other chemistry contained in the additive package do three things:
1) Metal inhibitors to keep metal ions from reacting with other chemistry in the oil from attacking aluminum, copper, and ferrous parts, and to keep them from catalyzing into carbonaceous deposits,
2) Rust inhibitors to keep ferrous metals from being corroded in the presence of moisture,
3) The calcium, magnesium, and other compunds provide TBN uplift and offset any acidic components that may form.

See also:

Additives XII-Multifunctional additives

As a review of additives, let us do this: Name at least one additive that functions in more than role. That is, name one or more of the Multifunctional additives. [ July 21, 2003, 07:20 PM: Message edited by: Patman ]

bobistheoilguy.com

The sulfur in those sulfonates described in post #14 are mostly inactive in terms of interacting with other compounds.

 

[MVAR]

Added to the VOA Database. I'm disappointed that Wearcheck does not test for starting Oxidation on virgin oil. I saw your Used Analysis of this oil and they list Oxidation there. Why not on virgin oil?

I also noticed they use D2896 TBN for both new and used samples. This method is only supposed to be used on virgin oil, never on used oil.

View attachment 225045

Received an email back from Wear Check. They are running the oxidation test on the VOA so there is a baseline. They stated that their normal policy for a VOA is oxidation has to be requested but there is no additional charge for the test.

The person I'm corresponding with wasn't sure about the D4739 vs D2896 reasoning but did state he should have an answer by the time the oxidation test is completed on the VOA.

Will update when I receive results.

 

[himemsys]

Received an email back from Wear Check. They are running the oxidation test on the VOA so there is a baseline. They stated that their normal policy for a VOA is oxidation has to be requested but there is no additional charge for the test.

The person I'm corresponding with wasn't sure about the D4739 vs D2896 reasoning but did state he should have an answer by the time the oxidation test is completed on the VOA.

Will update when I receive results.

Nice! Also good to know if I ever use WearCheck that oxidation must be requested on virgin samples.

 

[MVAR]

Nice! Also good to know if I ever use WearCheck that oxidation must be requested on virgin samples.

I posted the email response in the UOA thread (as you've already responded to) but I haven't received the test results of the oxidation run yet.

I'll be away from a computer for the next couple weeks (vacation ) but can post the value from my phone when I receive the email of test completion.

 

[burbguy82]

Sulfur containing compounds in lubricant Additives:

ZDDP (an ester of Zn[(S2P(OR)2]2); Zinc, Sulfur, and phosphorus.
Spikes, H. "The History and Mechanisms of ZDDP". Tribology Letters. 17 (3): 469–489, (2004-10-01).
Calcium and Magnesium Sulfonates
Molybdenum Dithiocarbamate or MoDTC (recall that a MoDTC compound formula is C4H8MoN4S8), or 4 carbon atoms, 8 hydrogen atoms, one or more moly atoms, 4 nitrogen atoms, and 8 sulfur atoms.

So any DTC compound is on the order of C4H8XxN4S8, where Xx is the metallic element containing one or more of the metallic atoms to create this organo-metallic compound.

So instead of all that, they just list the item in "sulphur" I suppose?