ENGINE OIL VISCOSITY PUZZLE

[Jaguar-EC]

The primary importance of oil viscosity:
"An oils first line of defense is its viscosity (thickness). The ability of the oil film to prevent contact between the rings and the cylinder is a function of an oils viscosity. Generally speaking, the more viscous or thicker an oil, the greater load it will carry."

Looking at the viscosity graphs for oils that are true full synthetics show a wide range of viscosities which means the high viscosity ones have viscosity modifiers added to the mix to artificially bring the mixes viscosity up. But my long standing question, which the engine oil manufacturers can't or won't answer is "Does artificially created higher oil viscosity provide more engine protection or is it done to just make the paying consumer think they are getting a higher quality product? Where are the product tests showing it isn't just another modern illusion?"

If they are adding a lot of viscosity modifiers then it should be reflected in the product price. Motul 800 Road Racing is 16% more costly than 800 Off Road and 800 Road Racing has around 20% more viscosity at 175C (a typical upper cylinder temp). Also Golden Spectro is mostly just Bright Stock, a mineral oil almost as good as group 2 mineral oil, and its viscosity is approaching that of the lowest synthetics which implies it has lots of viscosity modifier added to it and it does reflect in the price that is $10 more per liter than Motul 800 Road Racing.

So if my suspicions are justified then an oil ratio calculator should not go by the promoted product viscosities but by a formula that goes by the % of synthetic and mineral oil in each product, which is what I'm working on now, something that ignore whether or not viscosity modifiers have been added.

 

[MolaKule]

...The primary importance of oil viscosity:
"An oils first line of defense is its viscosity (thickness). The ability of the oil film to prevent contact between the rings and the cylinder is a function of an oils viscosity. Generally speaking, the more viscous or thicker an oil, the greater load it will carry."

Looking at the viscosity graphs for oils that are true full synthetics show a wide range of viscosities which means the high viscosity ones have viscosity modifiers added to the mix to artificially bring the mixes viscosity up. But my long standing question, which the engine oil manufacturers can't or won't answer is "Does artificially created higher oil viscosity provide more engine protection or is it done to just make the paying consumer think they are getting a higher quality product? Where are the product tests showing it isn't just another modern illusion?"...

A formulation without VII's can be made in any viscosity.

High Performance Lubricants No VII series engine oils.

Well it took a week longer than planned but we have the No VII series of oils put together. They are consistent with the respective PCMO and Euro series. https://www.hplubricants.com/wp-content/uploads/2023/01/No-VII-Engine-Oil-PDS.pdf

bobistheoilguy.com

What do you mean by "artificially created oils?"

In my line of work there are no illusions, just data to show a lubricant does what it is supposed to do and meets specifications.

What are the basis of your calculations, what formulae will you be using? Any links to the math formula's?

What makes you think that VII's are not already included in a commercial lubricant's price?

 

[sloinker]

A formulation without VII's can be made in any viscosity.

High Performance Lubricants No VII series engine oils.

Well it took a week longer than planned but we have the No VII series of oils put together. They are consistent with the respective PCMO and Euro series. https://www.hplubricants.com/wp-content/uploads/2023/01/No-VII-Engine-Oil-PDS.pdf

bobistheoilguy.com

What do you mean by "artificially created oils?"

In my line of work there are no illusions, just data to show a lubricant does what it is supposed to do and meets specifications.

What are the basis of your calculations, what formulae will you be using? Any links to the math formula's?

What makes you think that VII's are not already included in a commercial lubricant's price?

I know that some of the more expensive brands tout the major reductions in VI and to meet spec by using what is stated as a higher quality mix of group IV/V bases. I'm thinking the common understanding is the added VI has less life than the base stocks., especially when pushed to its limits. I'm not a scientist like you but this topic seems to come up in differing slants almost weekly.

 

[FowVay]

Before the discussion gets going too hot and heavy, note that these oils are all 2-cycle oils.

 

[sloinker]

Good point! I retract my previous post.

 

[BusyLittleShop]

Generally speaking, the more viscous or thicker an oil, the greater load it will carry."

Objectively speaking the great the flow the greater of load it will carry... this is the reason SAE grades oils on flow and not thickness...

 

[Cujet]

With regard to two stroke oil viscosity, I do know that manufacturers tested 20 viscosity and 30 viscosity oils for racing engines. I was involved in some racing two stroke outboard engine testing, along with oil ratio testing.

I don't believe 2t oils contain viscosity index improvers. What is typical is some form of dilutant to assist in mixing and/or for ease of pumping through a oil injection pump.

As to whether bright stock is up to the task, I'd give a qualified yes. For low stress engines.

What typically happens is that the oil partially separates from the fuel in the crankcase, and migrates through the crankcase at an RPM related rate. This means that the higher the RPM, the faster the "oil" moves through the crankcase and the less it is there to lubricate anything. Hence the need for more oil on very high RPM engines. As to whether the separated oil contains all of it's original qualities and thinners, I'd say no. Often the dye is less present in the migrating oil.

All things being equal, most modern two stroke engines can successfully use any quality oil, as long as enough is used. There are plenty of cases of 125cc motocrossers using TCW-3 oils at 16 to 1, with great success.

 

[MolaKule]

I don't believe 2t oils contain viscosity index improvers. What is typical is some form of dilutant to assist in mixing and/or for ease of pumping through a oil injection pump.

As to whether bright stock is up to the task, I'd give a qualified yes. For low stress engines.

I think the OP is mixing up his PCMO formulation technologies with two-cycle formulation technologies, but they are very different. There is no need for a VII in two-cycle formulations.

In TC oils, the majority of components are Multi-Functional Friction Modifiers/AW's where most of the friction modifier/AW's are one or more polyisobutylenes of various molecular weights. Older formulas used brightstock but brightstock leaves a host of deposits and residues.

In synthetic TC-W3 oils, the Multi-Functional Friction Modifiers/AW's are a combination of polyisobutylenes of various molecular weights and POE's of Trimethylol Propane (TMP) esters. The TMP esters can also do some cleaning of the combustion system while in aerosol form.

In some TC formulas, a Stoddard solvent or Cumene had to be added in order to get the brightstock and other heavy oils (Group I and II 30 grade oils) to go into solution, but TMP esters now take care of solubility issues.

Base oils may be Group III oils, and or some PAO's, but are minority components.

The additives are: a polyisobutenyl (ashless) succinimide dispersant, a phosphorylated Borate (another AW/Anti-scuff agent), and a combustion enhancer of either sulphurized oxymolybdenum dialkyl-dithiophosphate or a Titanium-compound.

 

[kschachn]

Objectively speaking the great the flow the greater of load it will carry... this is the reason SAE grades oils on flow and not thickness...

Wut? You have serious misconceptions about what oil does and how.

 

[CourierDriver]

I don't really care how much the atomic weight of something has or how its made. All I know is that 20w50 Mobil gets me there and back on the Harley . We don't ride easy thru the mountains in East Tennessee........ If it isn't smoking, I'm good.

 

[jeff78]

But my long standing question, which the engine oil manufacturers can't or won't answer is "Does artificially created higher oil viscosity provide more engine protection or is it done to just make the paying consumer think they are getting a higher quality product?"

The answer is yes.

What you're really getting when you pay the premium for a true real full synthetic is manmade oil molecules that are all identical and perfectly sized spheres which guarantees consistent and uniform lubrication performance, versus crappy nature-made dino oil which is made up of oil molecules of all uneven shapes and sizes resulting in inconsistent, inferior performance.

Where's that well-known photo when we need it? Seeing is believing.

 

[RDMgr]

2T oils don't normally contain VIIs. However, many contain a mid range molecular weight PIB for smoke control. Additives are ashless and may include FMs, AWs and dispersants.

 

[bonjo]

The way fully synthetic oil were promoted was based on the fact that the oil structure was engineered to achieve the desired property meaning that VII was not used. This may have been a lie or mis-representation.
I do not know if this holds true now since group 3+ oil can be labelled as synthetic

 

[Morganator]

Has anyone had a blown motor due to running the proper viscosity and changing oil at a regular interval?

 

[bonjo]

I don't think you get such dramatic failure unless you run the engine dry!
It is more like cancer, it damages the engine slowly through wear

 

[oil pan 4]

I say just pick a good CD rated synthetic and don't hold back.

Mild use frequently idling, part throttle not a whole lot of wot, quads, bikes, toys, ect 50:1

Medium use, some idling, some part throttle, more full speed and wot use such as chainsaws, generators, clippers 40:1
If it loads up with oil or fouls plugs retune or go back to 50:1.

Harsh use, little idling, lots of full speed, extended wot use such as saw mill chainsaws, leaf blowers, weed eaters, boat motors 32:1
If it loads up with oil or fouls plugs, retune or go back to 40:1.

 

[BusyLittleShop]

Has anyone had a blown motor due to running the proper viscosity and changing oil at a regular interval?

I haven't noted any blown motors due to significant wear... my 4 stroke race customer blow ups are the result from over revving pass red line or improper engine assembly or pump sucking air on their side...

Blackstone's 35 years worth of racing and street motorcycle oil
analysis shows no significant differences in WEAR between the grades
or brands... in other words either a Auto oil or a motorcycle specific oil
in grades 30, 40, 50, will meet and exceed your mileage expectations...

 

[Jaguar-EC]

>"I don't believe 2t oils contain viscosity index improvers"
Some of them have lots of VI improvers. This is easily known by using the online calculator to find the 200C viscosity from inputting the 40C and 100C viscosities. The worst case example is Redline Allsport. It only has something like 22% synthetic and yet its viscosity at 200C is way more than all the other fully synthetic oils. And I have reason to believe that those improvers have a reverse effect on lubricity although the higher viscosity a base oil has, the more its lubricity.

 

[kschachn]

>"I don't believe 2t oils contain viscosity index improvers"
Some of them have lots of VI improvers. This is easily known by using the online calculator to find the 200C viscosity from inputting the 40C and 100C viscosities. The worst case example is Redline Allsport. It only has something like 22% synthetic and yet its viscosity at 200C is way more than all the other fully synthetic oils. And I have reason to believe that those improvers have a reverse effect on lubricity although the higher viscosity a base oil has, the more its lubricity.

That would be a poor two-stroke oil. I agree that any quality 2T oil will not have VM.

And I don't think you understand how viscosity works and the role of base stocks.

 

[Jaguar-EC]

The lubricity is directly related to the base oil viscosity, before any viscosity modifiers are added. Notice how synthetic oils have a high viscosity and so can be added as half as much than mineral oils.