High CCS viscosity with Group V oil ???

[Tom NJ]

Originally Posted By: CATERHAM
Hi Tom,

Could you elaborate briefly on how the polar nature of esters is the reason for their low volatility and cleanliness?
Are some esters more polar than others?
Being electonegative, presumably the only metal they are attracted to are ferrous in nature? No attraction to aluminium alloys?


Esters have a positive and negative charge (polar) and as such they are attracted to each other. This intermolecular attraction requires more energy (heat) for the molecules to change from a liquid phase to a vapor phase, thus lowering the vapor pressure and volatility at a given temperature, while raising the flash point. For example, a 4 cSt POE has a Noack of 6% and a flash point of 480°F while a 4 cSt PAO has a Noack of 13% and a flash point of 425°F.

As for cleanliness, their polar nature makes esters good solvents which allows them to solubilize certain existing deposits and prevent new deposits by dissolving or dispersing degradation by products. There is a wide range of polarity among esters depending on the molecular weight, number of ester linkages, and branching. The attraction to metal surfaces is stronger with positively charged metals and alloys.

Tom NJ

 

[Thebimmerfan]

Originally Posted By: tig1
Originally Posted By: Thebimmerfan
Originally Posted By: HKPolice
Originally Posted By: SonofJoe
Group V base oils (typically esters) generally have worse cold-flow properties than PAOs and the very best Group IIIs. If you do the comparison, you'll find that your ester based oil will contain more VII and have a higher Noack; both undesirable traits.
Speaking personally, I never thought that much of esters and I certainly wouldn't regard them as any kind of base oil Holy Grail.


Yep, found a good chart here:


Polyol ester is much worse than PAO @ low temps. The only benefit of an ester based oil is high temp performance. I think most people automatically assume Group 5 is better than 4 in every aspect


Esters have more benefits than only superb heat resistance. Esters are polar - they adhere to the engine parts surfaces, eliminating the risk of metal to metal contact, which by the other hand is the worst thing which can happen inside an engine.
An ester's downside is their quite short life - ester-based oils need to be changed more oftenly.


And to imply other types of oil won't adhere to engine parts is deceptive. Most engines today last well over 200K with reasonable maintenance.


I didn't imply anything, you didn't understand my post. And it's a known fact that among all groups esters have best adhesion to metal surfaces. PAO although having many benefits doesn't stick to the metals, even some group 2 and 3 adhere better to engine parts than PAO.

 

[Tom NJ]

Originally Posted By: SonofJoe
It's true that esters can stick to metal surfaces but that isn't always a good thing. If ester out competes ZDDP to get to the metal, then you can find yourself with major wear problems. I've seen this very thing happen in a PAO/Ester based oil than chewed through cams like the ZDDP wasn't there!


Esters can interfere with (slow) the establishment of the ZDDP film if the engine is broken in with the ester oil. In engine tests, full ester formulations caused wear to rocker arm pivots only during the first two hours of the test, after which the ZDDP established itself and the wear stopped. Once the ZDDP film is established the ester has little effect, so esters are not a factor in engines broken in on conventional oils.

Tom NJ

 

[330indy]

Interesting and it's nice to have a POE expert here.
Do you like the Redline Break in oil product to supplement zddp for newer engines...?

 

[Tom NJ]

Originally Posted By: 330indy
Interesting and it's nice to have a POE expert here.
Do you like the Redline Break in oil product to supplement zddp for newer engines...?


I'm not familiar with the Redline formulation, but I would boost the ZDDP if I was breaking in a rebuilt engine. Otherwise no need.

Tom NJ

 

[Nickdfresh]

Originally Posted By: ST2008
Originally Posted By: MolaKule
Why do you think some engine oils are predominately Group V oils?


It's what I understand that the base oils of Motul and Redline are made of Group V oil.


They're probably not, their street oils contain a lot of Group IV and probably III as well. The Group V thing is a fanboi myth based on some of their racing oils...

 

[Jetronic]

I learned how to spot esters and their approximate concentrations from IR spectroscopy.

MOTUL 300V ESTER CORE 5W-40 contains about 10% esters if my observations are correct, and redline 5w-20 about 40%. Redline 0w40 about 25-35%. But it seems the results vary depending on the exact type of ester used, so concentrations are approximately.

Most Motul oils indeed don't contain esters, or extremely low concentrations (under 5%).

 

[Nickdfresh]

I would find it difficult to believe Motul contains no esters. They would need it for additive solubility...

 

[Jetronic]

not really. additives are solubilized in group I/II oil from the supplier

 

[330indy]

Originally Posted By: Nickdfresh
Originally Posted By: ST2008
Originally Posted By: MolaKule
Why do you think some engine oils are predominately Group V oils?


It's what I understand that the base oils of Motul and Redline are made of Group V oil.


They're probably not, their street oils contain a lot of Group IV and probably III as well. The Group V thing is a fanboi myth based on some of their racing oils...


Fan boys
Right

Group V category oils are superior, in VI and real world performance. What out there is even close to Redline?

 

[deven]

Originally Posted By: 330indy
What out there is even close to Redline?

Deleted post