Synthetic Engine Oil Base Stocks

[nova3930]

I hear ya, cowpie1, but (1) how do we know what the base stocks actually are for any given synthetic oil marketer and,

I ask the question, why does it matter what it's made out of? The question I would ask is "does it meet my performance requirements?" The performance is what matters in the end.

(2) how can SOPUS/Shell/Pennzoil claim their synthetic base stock is 'made from natural gas' and still only be an API Group III which, by definition, is a severely hydrotreated refined crude? Natural gas can not be 'refined' nor hydrotreated, it can only be synthesized into longer chain hydrocarbons, which, by definition, is a synthetic manufactured Group IV.

I think it's not Group IV because Group IV is specifically PAO. Here's API 1509, Appendix E.

http://www.api.org/certification-pr...sel/publications/appendix-e-rev-09-01-11.ashx

Here's there definition of "base stock"

E.1.2.1 A base stock is a lubricant component that is produced by a single manufacturer to the same
specifications (independent of feed source or manufacturer’s location); that meets the same manufacturer’s
specification; and that is identified by a unique formula, product identification number, or both. Base stocks may
be manufactured using a variety of different processes including but not limited to distillation, solvent refining,
hydrogen processing, oligomerization, esterification, and rerefining. Rerefined stock shall be substantially free
from materials introduced through manufacturing, contamination, or previous use.

Group III Base stock is defined as greater than or equal to 90% saturates, less than or equal too 0.03% sulphur and have a viscosity index greater than or equal to 120. It says nothing about process used to make it.

c. Group III base stocks contain greater than or equal to 90 percent saturates and less than or equal to 0.03
percent sulfur and have a viscosity index greater than or equal to 120 using the test methods specified in
Table E-1.

Group IV is specifically designed as PAO

Group IV base stocks are polyalphaolefins (PAO). PAOs can be interchanged without additional qualification
testing as long as the interchange PAO meets the original PAO manufacturer’s specifications in physical and
chemical properties.

So if you're liquefying natural gas to create a base stock that meets the GIII criteria, it's a GIII....

 

[3930dave]

I hear ya, cowpie1, but (1) how do we know what the base stocks actually are for any given synthetic oil marketer and, (2) how can SOPUS/Shell/Pennzoil claim their synthetic base stock is 'made from natural gas' and still only be an API Group III which, by definition, is a severely hydrotreated refined crude? Natural gas can not be 'refined' nor hydrotreated, it can only be synthesized into longer chain hydrocarbons, which, by definition, is a synthetic manufactured Group IV.

It is more than academic - the base stock does most of the work in terms of the actual lubrication & film strength that separates moving parts, hence directly affects part longevity. In addition, the most saturated & uniform base stock also provides the most resistance to breakdown, whether by shearing or oxidation - despite the additive packs.

So, not only do I want to know what I am getting for my money, I want to be able to choose what I am getting for my money, and all the marketing obfuscation prevents me, the consumer, from being able to do that. Hence my rant.

:hissyfit:

From an application standpoint (as in, my vehicles) I can live with something like a Rotella T6 having consistently good UOAs on BITOG. Most of the time, that satisfies my personal good enough metric.

But yes, I also get a little irritated by the obfuscation you speak of. If you ask directly (III vs. IV), I wouldn't expect to get a straight answer from most oil companies, concerning N. American marketed synthetics. You can take a guess, by looking at the recommended extended drain mileages - with the higher mileage ones more likely to be IV.

As a customer (ie. I don't sell their stuff), I've had prompt technical responses from Amsoil re. things like ZDDP, you may ping them on this and get a straight answer.

It might take a VPN tunnel, but you may also learn something from Euro market advertising, specifically Germany. A few of their Castrol products make it over here, and something like Motul is low volume enough (here) that I suspect that it wouldn't be worth their while to bottle a (watered down) version for our market. Last I knew, only a IV could be marketed as synthetic in Germany.

I need a third hand (OTOH already used) making this next point..... for the mass market here (meaning other than OCD oil-geeks like us :thumbsup I can see that presenting the choice as Do You Want To:

A) Stick with OE change intervals ?
or
B) Go with 25,000 mile/one year intervals ?

Is a question that is easier to get people to consider, than III vs. IV.

Rgds, D.

 

[DeereMann]

Thanks for soothing my itch, fellow tribologists.

I would ask nova3930........PAO also satisfies Group III definition. So what allows PAO to be labeled PAO?

It seems Group III base stocks have some physical limits to meet, whereas Group IV does not. They just have to be 'PAO'. I would think if SOPUS makes from natural gas, these COULD be both Group III AND Group IV, no? So why wouldn't they advertise same?

These guys are all snake oil now. Bugs me. It was simple in the 80's & 90's.

 

[nova3930]

Thanks for soothing my itch, fellow tribologists.

I would ask nova3930........PAO also satisfies Group III definition. So what allows PAO to be labeled PAO?

The fact that it's PAO. Poly Alpha Olefin is a specific organic chemical configuration. At some point the powers that be at API said "yay verily anything made out of PAO is Group IV" and that really is the only reason PAO is called Group IV.

At the end of the day, all these standards are entirely arbitrary. They put a bunch of engineers in a room and tell them to define some repeatable values with which they can separate things into separate boxes.

It seems Group III base stocks have some physical limits to meet, whereas Group IV does not. They just have to be 'PAO'. I would think if SOPUS makes from natural gas, these COULD be both Group III AND Group IV, no? So why wouldn't they advertise same?

I assume they could if they were making PAO from the NG but chemically I don't think they're doing that. I think they're using some variation of the Fischer–Tropsch process to produce a very pure petroleum using gas fractions that would normally be flared and wasted. Regardless of how pure it is, if it's not PAO it's not Group IV.

 

[DeereMann]

This leads me to wonder what SOPUS 'synthetic' Group III base stock actually is (chemically)? In fact, one would think it would be more expensive to polymerize methane (natural gas) into a base lubricating oil than the ethylene/decene gases used to make PAO.

I would guess SOPUS Group III synthetic base oil stock is closer to the desired PAO molecular structure than that from hydrotreated/cracked crude sources - important because Group III API 1509 definition only defines minimum physical properties - perhaps SOPUS Group III significantly exceeds these, yet can not be called Group IV due to some radical isomers on the carbon chain. i.e. - it would be 'almost' Group IV and far better than other's Group III's.

I know Group III minimum properties are pretty high - but I'm just saying maybe a new oil like SOPUS 'PurePlus from natural gas' IS actually significantly better and provides markedly better performance for the same price owing to the molecular structure of the base oil stock?

See what I mean by getting the best oil for the money?

Of course, none of the oil marketers want us to have any facts whatsoever, and so it goes.

 

[DeereMann]

Check out this link from Shell website --> Shell Creates Motor Oil From Natural Gas - United States

I wonder how close their Gas-to-Liquid (GTL) process is from creating PAO? And.....how different the resultant oil is molecularly?

I think either GTL or PAO has distinct advantages over crude-refined API Group III base oils - both are synthesized from pure base materials. Other Group III's are not - e.g. - severely hydrocracked crude oils. Which means they will still contain some level of impurities, however small. Which means they will degrade faster, however slowly, and oxidize faster, however slowly.

This is why I switched from Mobil 1 to Shell/Pennzoil PurePlus synthetic recently.

 

[Z71]

An oil company can use a high end base oil but then use mediocre additives. They are also usually constrained on buying all the additives from themselves and not search world wide for the very best additives and use them. Why do you think some oils are cheaper? Did they use cheaper oil base stocks and additive packages? Did they cut back on quality control? How can they afford to spends millions of $$ on advertising and still make money if they claim their oil is best?

At the end of the day, the type of base stock used to formulate the oil is inconsequential; the product’s performance is what matters.

 

[DeereMann]

I respectfully disagree, based on my experience. The base stock of the lubricating oil is the critical component to determine how well the machine elements are lubricated (antiwear), and contributes heavily to oil resistance to oxidation - despite supplemental additives.

I learned this in my years as a Lubrication Engineer for Mobil Oil Corporation.

 

[jix]

Learned gentlemen:
I have carefully read this whole thread. It made my brain hurt, and I am a Techie type with oil refinery lab experience.

I like simple answers. Complex answers just confuse me. So my conclusion from all that I have read here is just to use Rotella T6 (10-30) oil from wally world in my little 3 cyl diesel Kubota..and change it at 200 hour intervals, with the filter included. Is that a fair conclusion, would you say?
Is that a simple and correct answer? Kubota brand oil is way too needlessly expensive IMO.

 

[DeereMann]

Yes - IF you don't run in ambient temperature above 90 degrees. If you do, then go to 15W-40.

This thread was meant as a marketing rant, not generic engine oil advice, btw, but happy to reply regardless.