Will the chemistry of low visc oils catch up to physical properties of thicker ones

[Kamele0N]

Originally Posted by StevieC


If you read above I actually stated that thicker oils have their place such as severe duty like towing (or heavy loads). This would be why. We are talking about your average vehicle running around everyday driving.


Ok....lets say...it is plausible to go away with that oily water

BUT! Thats in "your" world....where 5.0L V8 has about 200-300HP....

If I look around the parking lot right now...there are plenty of cars with 0.9- 1.2-1.5L turbo engines with 100HP & up to 150HP...and many of them are even tweaked (chiptuning)....and these are our daily bangers here... Like Renault Clio.... Vw Golf... Peugeot 208...


So you can have your thin ILSAC/Cafe/..... oil for your "lawnmovers" on 4 wheels (look at HP/L and you will see that basically you are driving a lawnmover

)

 

[Shannow]

Originally Posted by CR94
Originally Posted by MotoTribologist
... When the engine and ambient temperatures are hot and the 0-20W oil is "acting" like a 20W oil, isn't the viscosity the same as the viscosity of the 20W oil I used in my '52 Ford V8 ? ....
... So the "20W" you used in the past was likely a 20W-50 or thereabouts, just not labelled for the high temperature spec.
Wouldn't it more likely have been a 20W-20 in the 1950's?
[/quote]


monograde 20s have HTHS in the 2.9 range.

See Redline, see Amsoil Dominaotr, see Citgo minerals.

 

[PimTac]

Originally Posted by Kamele0N
Originally Posted by StevieC


If you read above I actually stated that thicker oils have their place such as severe duty like towing (or heavy loads). This would be why. We are talking about your average vehicle running around everyday driving.


Ok....lets say...it is plausible to go away with that oily water

BUT! Thats in "your" world....where 5.0L V8 has about 200-300HP....

If I look around the parking lot right now...there are plenty of cars with 0.9- 1.2-1.5L turbo engines with 100HP & up to 150HP...and many of them are even tweaked (chiptuning)....and these are our daily bangers here... Like Renault Clio.... Vw Golf... Peugeot 208...


So you can have your thin ILSAC/Cafe/..... oil for your "lawnmovers" on 4 wheels (look at HP/L and you will see that basically you are driving a lawnmover

)





No sense in getting a straight answer here. Besides, what's a lawnmover?

 

[Kjmack]

I cut 5 acres of grass about every 5 days . i use 0w40 in my lawn tractor , if i switch to 0w20 will i use less gas ?

 

[oil_film_movies]

To summarize: All the papers and tests, plus some intuitive understanding thrown in:

Thinner oils of the future and current ones too, get better wear at start-up than thicker oils. Gain there.
Thicker oils give you more hydrodynamic % of surfaces running, where there is zero wear rate.
Thinner oils with a ton of moly or something like it gives better boundary condition wear rates than thicker oil.
Thinner oils gain on reducing start-up wear, and lose a little from the difference between the % hydrodynamic of thin vs. thick, and then thinner oils gain on reducing wear during boundary conditions.
NET RESULT: Add up all conditions. See the entire driving spectrum. Thinner oils can win, do win currently very often, and that's why they are the future.

Again, for emphasis, the start-up wear argument has been settled by:
-6000 CCS delta: 5x wear rate from tests...
-4000 CCS delta: 2x wear rate guessing conservatively
-1000 CCS delta: 1.2 wear rate guessing
-500 CCS delta: 1.1 wear rate guessing

 

[Shannow]

Re the importance of the word "some", and why a one off change of viscosity in a Jeep doesn't overwrite decades and decades of science.

https://www.sae.org/publications/technical-papers/content/922342/

Quote
Two programs were conducted to study the relationships between engine oil rheology and crankshaft bearing wear. A Chassis Dynamometer test of four oils in four cars was used to explore and define the key variables affecting bearing wear. These results were used to design a Field Test of nine oils in 45 taxicabs in New York City. The test oils (SAE OW-20 to 20W-20) were formulated to measure the effects of viscosity, viscosity index improver, and detergent inhibitor package. Bearing wear tended to be either low and unremarkable or very high, particularly in the thrust bearings. Oil performance was best expressed as the frequency of excessive wear, rather than by quantitative wear measurement. There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. Non-Newtonian oils appeared to provide slightly more protection than Newtonian oils of the same HTHS viscosity, and a higher quality adpack also appeared to provide benefits. However, these factors were secondary to the viscosity of the oil. HTHS viscosity was a better predictor of bearing wear performance than oil film thickness.


And fully supports the views of Infineum and Lubrizol that I shared, not the cherry picked single half sentence...

 

[PimTac]

I have never seen a 20w20 oil here. That's a odd duck.

 

[oil_film_movies]

Originally Posted by Shannow
Re the importance of the word "some", and why a one off change of viscosity in a Jeep doesn't overwrite decades and decades of science.https://www.sae.org/publications/technical-papers/content/922342/
You accidentally disproved your point. HTHS 2.6 is no different than HTHS 3.0. Remember 0w20 oils have HTHS typically around 2.7.

 

[Shannow]

Originally Posted by oil_film_movies
Originally Posted by Shannow
Re the importance of the word "some", and why a one off change of viscosity in a Jeep doesn't overwrite decades and decades of science.https://www.sae.org/publications/technical-papers/content/922342/
You accidentally disproved your point. HTHS 2.6 is no different than HTHS 3.0. Remember 0w20 oils have HTHS typically around 2.7.

No I didn't...but you can think that anyway...If your thought process is linear, I can see you grasping that conclusion, and was fully cogniscent of that fact that your type would seize on it...but posted it anyway.

So congratulations.

 

[Shannow]

Here,
have at it...
https://hondakarma.com/data/attachm...owertrains_Fuels_and_Lubricants-2010.pdf

Note that Honda are increasing bearing dimensions while they chase piston skirt wear...ie. changing bearing dimensions for durability, and therefore increasing drag in that area to get impovements in pistons and rings.

Linear thinkers, like many in this thread and others, don't get the idea of tradeoffs.

 

[nap]

I'd say that if we're going to restrict the comparison to only "some" engines and under "specific" circumstances, we could start with the case of using 0W16 as a preservation oil for engines in storage. Then the thin camp could finally have some real chance with the "matches or exceeds" comparison with thicker oils.

 

[StevieC]

On page 7 where they have the charts of HTHS it shows that there is virtually no different between 2.3's and 3's for wear.

Then it goes on to say that grades lower than 20 weights will need additive packs that compensate for the lower HTHS and MOFT.

I'm still having a hard time seeing how 20 weights are a problem under normal engine circumstances ???

 

[nap]

You gents are looking at the wrong charts. To see something happening at hths 2.6 you would need to look at the ring / liner or camshaft wear. There's a study from Toyota including them. The bearings start to show wear only later.

 

[JAG]

Ring and cylinder wear is the wear that most concerns me, especially near top-dead-center where speed is slow or zero, oil film temperature is the highest in a non-turbo engine, and cylinder pressure is high during combustion stroke. That area does not have hydrodynamic lubrication. I have worn out the rings and cylinders of an engine before: 1984 BMW 318i.

 

[nap]

Let's not forget the timing chains, 3 of the engines listed here are wearing them way too fast:

https://www.wheels.ca/top-ten/seven-engines-to-avoid-like-the-plague/

As a bonus, one of the engines there had to be back specced to 5W40, as 5W30 was deemed to be too thin... "where are all the blown engines", eh?

 

[wemay]

So some areas benefit more from Boundary Lubrication and others, Hydrodynamic? Meaning each has it's place where wear is concerned depending on where in the engine the focus of the discussion is?

 

[StevieC]

Originally Posted by nap
Let's not forget the timing chains, 3 of the engines listed here are wearing them way too fast:

https://www.wheels.ca/top-ten/seven-engines-to-avoid-like-the-plague/

As a bonus, one of the engines there had to be back specced to 5W40, as 5W30 was deemed to be too thin... "where are all the blown engines", eh?


Poor engineering, or poor component quality, not the lubricants fault. Lots of engines run just fine on 5w20 conventional for long lives and other do on the 20wt synthetics version with timing chains and we don't see those being recalled, back spec'ed. Also you might look at the OE's involved with these. Not exactly the best reputations for build quality in general.

 

[CR94]

Originally Posted by Shannow
... monograde 20s have HTHS in the 2.9 range. ...
... as you've stated many times.

 

[Shannow]

Originally Posted by StevieC
On page 7 where they have the charts of HTHS it shows that there is virtually no different between 2.3's and 3's for wear.

Then it goes on to say that grades lower than 20 weights will need additive packs that compensate for the lower HTHS and MOFT.

I'm still having a hard time seeing how 20 weights are a problem under normal engine circumstances ???


I'd suggest that you re-read the title and opening premise of the thread...that's where the discussion started, before the fixation on 20, and one Jeep.

You have less "headroom" with your 20 if things go bad (e.g. cooling system issues), there's another paper that I can dig up on that one that "proves" (again in the test engines) that a mild overheat needed 3+ HTHS ("proves" in the sense of the way you guys are using the word, not the way it's traditionally used).

Ford, Toyota, Subaru are installing Nannies that cut the power from rated power when temperatures climb...controls that weren't that necessary a few decades ago...I guess nannies on engines lubricated with 20s "proves" something too...

 

[CR94]

Originally Posted by JAG
Ring and cylinder wear is the wear that most concerns me, ... I have worn out the rings and cylinders of an engine before: 1984 BMW 318i.
Using what viscosity oil?
I couldn't find any ridge at the top of the cylinders in my Mazda when the head was off at 476,402 miles.