Another oil thread

[VicFirth]

Shear stability comparison.

 

 

[Grumpy Bear]

^^^^

This

[customboss]

On 7/5/2024 at 6:59 AM, VicFirth said:

Shear stability comparison.

 

 

What a waste of time for informed folks. For the uninformed it’s not the whole story. 
 

Proves standardized bench testing can  accurately reflect engine testing. 
 

One of the benefits of polymeric shear is reduction in friction. That design shear is a key to mpg gains and no one purposely designs an engine or engine oil that’s allows harmful wear. 
 

A different point of view. Note Mobil1 0w-40 is one of the finest low wear formulas for anyone who uses even the new version. Having tested that brands current chemistry and earlier versions ( for 40 years) they all shear to SAE 30 @ 100C or near it and function perfectly giving excellent wear control and provide excellent long over the full drain fuel economy boost. 
 

 

[Grumpy Bear]

The POINT of lubrication is wear control. Shear for economy?  Use a lighter oil if that be the goal. Oh, wait, they are already doing that.

 

No, they don't ALL shear down a grade. Rubbish. Pay attention. 

[Grumpy Bear]

The industry has changed 'focus'. Forced to. Government regulation. But this did not change physics. Stribeck didn't become irrelevant. GM/Honda wear studies were not invalidated. Common sense didn't die. The focus changed. From wear to economy. But it's a hard sell to cut engine life by 30% to gain <5% in fuel efficiency. You have to lie from the heart. 

 

The puzzling part is people that call themselves "tribologist' ignoring reality to follow the mandates and the madness. You can't wish or buy the laws of the universe to bend to your goals or needs. Try to cancel gravity and let me know how that works out. 

 

Since the first guy on earth used animal fat to lubricate the axle, the goal has been to make the assembly last LONGER and kids it does so because it runs freer. That is wear oriented focus. Saying that isn't so just undermines one's credibility as a tribologist.

 

But humans are human and what is good for them is seldom what they will chose. 

 

You want my attention? The kind you don't want. Tell me I'm not seeing the thing I'm looking at. Not hearing the thing I'm hearing. The sun will rise form the west tomorrow because you need it to. Tell me your million years of experience says it will happen. Be irrational and you will have it. 

 

Know what you won't have? A handle on the truth. 

 

Truth is energy required to spin a rotating assembly is not JUST a function of viscosity. It is also a function of LUBRICITY. Every play shuffleboard?

 

Use your head for something more than a hat rack. 

[OnTheReel]

Shear isn’t a fault, it’s a feature. SOPUS and XOM will gladly deliver it in exchange for those sweet license deals. 

[Grumpy Bear]

7 hours ago, OnTheReel said:

Shear isn’t a fault, it’s a feature. SOPUS and XOM will gladly deliver it in exchange for those sweet license deals. 

 

You won't believe this, but the exact line was playing in my head on my pillow last night.  

 

***************************

Comments not directed at the quote: 

 

When ZDDP was first used it was so as a corrosion inhibitor. Just so happened it wore more than one hat. Wear control and antioxidant. So, focus changed to its wear properties but that didn't make corrosion inhibiting all the sudden untrue. 

 

The fact cheap VM polymers shear wasn't by design. It just became useful to a new cause about 50 years after their introduction. Which begs a question. If it were by design, why so much effort to develop more expensive ones that didn't? C'mon man.... Head, hat rack, wake up....

 

Friction reduction is important but when you take it to the point of sacrificing wear control.... The fact one can get away with it for longer than most people own a car and longer than most warranties is not a brag a person should be making. 

 

The first two little pigs didn't boast their houses of sticks and straw kept them alive just because it made the wolf chase them to the brick house.

 

[customboss]

Which VII are you speaking to?

 

Polymethacrylate, polyisobutylene, hydro styrene diene copolymer, and ethylene-propylene copolymer are used as viscosity index improvers. 
 

 

[customboss]

In 1968 GM wrote a paper on issues with VII. Guess what the deposits issues with Pennzoil and Quaker State lubes was from that time to mid 70’s? Poor quality  VII not those oils base oil chemistries. 
 

That’s when Grumpys knowledge stopped I guess. 
 

Here’s a link below to study up on modern market. 

 

Lubrizol and others market versions that rival base oils in WEAR control. 
 

Guess which versions high quality oils use? 
 

https://www.futuremarketinsights.com/reports/viscosity-index-improvers-market#:~:text=Polymethacrylate%2C polyisobutylene%2C hydro styrene diene copolymer%2C and ethylene-propylene copolymer are used as viscosity index improvers.

Do I personally prefer additives to high quality base oils? Negative. But if you are gonna bash a category of chemistry additives at least indicate which one and why. 
Put a hat on that bald head Grumpy.

[customboss]

Read up. High quality VII shows LESS droplet transfer into crankcase venting than PAO alone. 

https://link.springer.com/article/10.1007/s11249-022-01589-0

 

Edited July 8, 2024 by customboss
Add pic

[customboss]

https://www.stle.org/files/TLTArchives/2022/11_November/Lubrication_Fundamentals.aspx

 

The ring designs and cylinder cross-hatching are part of the engine design to control the oil in the combustion chamber, but the multigrade engine oils also help control the oil consumption rate. Multigrade oils are formulated with viscosity index improvers (VII), which are long polymers that uncoil as temperature rises, effectively increasing their size and the oil’s viscosity. At low temperatures, these polymers coil up again to return the oil to its original viscosity. This reduces the rate of change of viscosity with temperature and makes possible the formulation of multigrade oils. Multigrade oils allow for easier start-up and quicker oil flow throughout the engine during cold temperatures and yet provide enough lubricant film at high temperature to protect the moving components of the engine. These VII additives also exhibit temporary viscosity loss under the high stress of the ring and cylinder wall area. This temporary lower viscosity helps reduce the amount of oil that enters the combustion chamber.

Counterintuitively, a higher viscosity oil does not reduce oil consumption and may actually increase oil consumption. Using a higher viscosity oil will increase the engine oil pressure, which may stop the “low-oil pressure” alert, but over time the higher viscosity may lead to more oil in the combustion chamber. A caveat on this is that a higher viscosity oil may slightly decrease oil leakage, but not for long. High mileage engine oils may have a better fix to oil leaks.

 

Food for thought from one of your Chevron pals. 

[txab]

Oh, oh. Let dick measuring begin again.

 

 

Everyone pull up a chair and prepare for further education using big words 

 

Edited July 8, 2024 by txab

[txab]

Once you hear or see the word Tribology, you have to pull up a chair

[Grumpy Bear]

Small words. Go Fish! 

 

I don't speak German, French or Irrational. Do we know all those words? 

 

Machines surfaces are ROUGH. No matter how fine the surface finish it has asperity. (Lord, I hope the word asperity isn't too big). 

 

Stribeck tells us that to keep rough parts from touching rough parts you have to have a low enough load, a fast enough velocity and enough VISCOSITY to fill the valleys, cover the peaks and create a sufficient thickness between the two to keep the peaks from dragging on each other. How much viscosity is required varies throughout the motor. How much viscosity is present depends on the base oil and its temperature. 

 

UNTIL this happens think WEAR. This is not a hard concept. The Hersey number tells us that if you increase load, reduce speed, increase temperature beyond the base oils viscosity bad things happen. WEAR

 

Today's plateau finishes quicken the break-in but do NOT have a smaller valley nor a lower film requirement than a rough hone once fully bedded in. In fact the valley volume is LARGER. 

 

Bores are not the only surface in the motor. 

 

Look, AW adds are there to pick up the slack when you lose the film as in startup or momentary film thickness loss. They ARE NOT there to be THE normal running surface. They are sacrificial. 

 

Rough rule of thumb that will NEVER get canceled anywhere but in a few hardheaded minds is 10 cP at 100 C. What it takes to keep parts from touching parts. If you have that much then if you can KEEP it, all circumstances within that motor that will and do alter this viscosity will be covered.  If anything since the number became a touchstone,  it has changed UP, not down. More load (small displacement big boost), less speed (higher gearing, lower engine speeds), thinner base oil viscosity, (8, 16, 20 weights with HTHS values below all known usefulness in anything but a turbine bearing) higher oil and water temperatures (water now hovering 210F nominal and sump temperatures 50 F higher than a few decades ago), fewer AW adds (those pesky phos, sulfur, zinc devils) ..... If you have two brain cells that know each other this isn't magic or even hard to comprehend. 

 

There is no free lunch with viscosity. You have enough or you don't, and it won't change because you have a goal or wish or even really bad advice.  

 

You want to follow Pied Piper off a cliff. Have at. 

 

 

 

Me, I'm not looking for followers. Don't think I'm inclined to even try to be helpful anymore.  

Edited July 9, 2024 by Grumpy Bear

[Grumpy Bear]

Shear Strain Profile

 

 

ZDDP is a phosphate ester.

 

Focus on the Ester and Mineral oil. Viscosity reduction may be a CHEAP way to reduce the fluids internal resistance but it has a cost. Film thickness loss. Esters reduce friction while maintaining film thickness without the need to reduce viscosity. 

 

Neat trick. Blend about 15% NPG Ester with 85% PAO. The Ester is polar and has an affinity for iron so the layer next to the wall/ring is ester and the PAO then slides over the ester in Planar Shear with less resistance than the POA will slide over itself or the metal. The result is lower friction with the same or even increased film thickness. 

 

We have the technology. We just don't like to use it, but it COST so everybody with a dog in the fight try's to cancel the truth for profit. Even some without a dog in the fight. Funny because ester by and large are biodegradable. POA is not nor is AN or Mineral oil. So you don't use the thing that would help because it cost too much, to use something that hurts by increasing wasted resources, (extra cars). 

 

There are now many companies making mid saps oils with PAO/POE bases at reasonable pricing and still we resist. 

 

WHY?