Another "Taxi" Study: Relationship of Engine Bearing Wear and Oil Rheology 872128

[AEHaas]

I have presented all sorts of papers/evidence that off the shelf, modern motor oils labelled as having HTHS of 2.5 or more work well in automotive engines. It does not matter if, in use, there is shear or fuel dilution, they work fine. The thick people seem to say that wear can only be tolerated if the grade is a 40 or more and that they do not care about fuel economy. Fine, then use a 60 grade or thicker oil, as always stated, more MOFT = less wear. I am not denying it although it is not always directly related. And as mentioned in some of the scientific papers, even the investigators argue this point.

For many it must be difficult to understand that 1 nanometer of wear, nor twice that, 2 nanometers is still no wear at all, even though one is twice the wear of the other. 'Never thought it was a difficult concept but apparently it is. It is a political or religious thing I guess. No amount of evidence can convince the other side of anything. Anyway, I think I am pretty much done for now. I did the best I could.

Best wishes,

Ali

 

[ZeeOSix]

assumptions...

Didn't Neo have a 0W-5 when the lowest grades were xW-20? I recall it wan't much thinner, if any, than a 20.

Yeah, would have to compare the actual measured viscosities. But if whoever called their oil a "0W-5" knew how SAE J300 grades oils, then I'd have to venture to say the 0W-5 would most likely have a lower KV100 than a 0W-8 since it would indicate a lower viscosity grade. Unless the guy giving the "0W-5" it's "grade" designation was trying to pull a fast one with smoke and mirrors, lol.

 

[demarpaint]

I have presented all sorts of papers/evidence that off the shelf, modern motor oils labelled as having HTHS of 2.5 or more work well in automotive engines. It does not matter if, in use, there is shear or fuel dilution, they work fine. The thick people seem to say that wear can only be tolerated if the grade is a 40 or more and that they do not care about fuel economy. Fine, then use a 60 grade or thicker oil, as always stated, more MOFT = less wear. I am not denying it although it is not always directly related. And as mentioned in some of the scientific papers, even the investigators argue this point.

For many it must be difficult to understand that 1 nanometer of wear, nor twice that, 2 nanometers is still no wear at all, even though one is twice the wear of the other. 'Never thought it was a difficult concept but apparently it is. It is a political or religious thing I guess. No amount of evidence can convince the other side of anything. Anyway, I think I am pretty much done for now. I did the best I could.

Best wishes,

Ali

FTR I think many of "The thick people" are referring to 30 grade oils, not 40 or more. Regarding evidence, the knife cuts two ways, the thick people presented plenty as well. Which imo is more compelling.

 

[ZeeOSix]

I have presented all sorts of papers/evidence that off the shelf, modern motor oils labelled as having HTHS of 2.5 or more work well in automotive engines. It does not matter if, in use, there is shear or fuel dilution, they work fine. The thick people seem to say that wear can only be tolerated if the grade is a 40 or more and that they do not care about fuel economy. Fine, then use a 60 grade or thicker oil, as always stated, more MOFT = less wear. I am not denying it although it is not always directly related. And as mentioned in some of the scientific papers, even the investigators argue this point.

Nobody is claiming that oils with a HTHS viscosity of 2.5-2.6 cP or higher don't work well in automotive engines. They are saying at the 2.5-2.6 HTHS viscosity point, the testing shows that wear rates on some engine components can start to noticeably increase. Is that start of increased wear rate "acceptable" to many ... yes, it seems to be that way since many vehicles were 'back speced" in the name of CAFE. It's been shown many times, and even you have acknowledged that. But when oils with much less than 2.5-2.6 HTHS viscosity are used it's shown in those same studies that the wear rate is even higher the lower the HTHS viscosity decreases - all other factors held constant.

But that doesn't mean that a lower wear rate, and less long term wear doesn't happen and isn't beneficial to engines. Yeah, then this is when people start chiming in with "but the car will rust out before the engine dies" or "you'll trade it in before the engine dies" or "it will probably get totaled in an accident before the engine dies" ... etc. But some people just don't think that way. For those who do ... whatever floats the boat. There is nothing bad about a thicker oil providing more HTHS, more MOFT for added engine wear protection headroom. Nothing "bad" about a little thicker oil expect maybe a sliver of less fuel mileage. Engines don't get damaged from thicker oil (within reason, and with the right "W" rated oil), but engines certainly can get damaged and wear more from an oil that is too thin.

For many it must be difficult to understand that 1 nanometer of wear, nor twice that, 2 nanometers is still no wear at all, even though one is twice the wear of the other. 'Never thought it was a difficult concept but apparently it is. It is a political or religious thing I guess. No amount of evidence can convince the other side of anything. Anyway, I think I am pretty much done for now. I did the best I could.

Best wishes,

Ali

That seems to just a justifying example, because I'm sure you have zero technical evidence what the real maximum wear difference would be. Is the example of 1 nm vs 2 nm with 1 hour of run time, or 200k miles of run time? Only controlled testing could nail down the differences in wear rates over X amount of run time or equivalent miles. When oils are ran per the API test specs for wear, their run time isn't that much ... way less than what an engine in the real world would run. If they saw the wear rate was double after 100 hours, what's that extrapolate out to the actual cumulative wear difference on an engine with 250K miles on it (?).

 

[edhackett]

Fuel %Vol ____ Vis CS 100C __ 15.8....11.8….8.6….9.8

Note the resistance to viscosity drop in the newer 0W30 formulation despite more fuel dilution.

Ali

How can I note the resistance to viscosity drop without knowing the initial viscosity of each formulation?

Ed

 

[Bill_W]

I have presented all sorts of papers/evidence that off the shelf, modern motor oils labelled as having HTHS of 2.5 or more work well in automotive engines. It does not matter if, in use, there is shear or fuel dilution, they work fine. The thick people seem to say that wear can only be tolerated if the grade is a 40 or more and that they do not care about fuel economy. Fine, then use a 60 grade or thicker oil, as always stated, more MOFT = less wear. I am not denying it although it is not always directly related. And as mentioned in some of the scientific papers, even the investigators argue this point.

For many it must be difficult to understand that 1 nanometer of wear, nor twice that, 2 nanometers is still no wear at all, even though one is twice the wear of the other. 'Never thought it was a difficult concept but apparently it is. It is a political or religious thing I guess. No amount of evidence can convince the other side of anything. Anyway, I think I am pretty much done for now. I did the best I could.

Best wishes,

Ali

If bearings do not operate in hydrodynamic range but operates in mixed range with contact you will know it in short order. That is why wear on the scale you are saying is not relevant. One thing is wear will happen, but what kind of wear?

 

[OVERKILL]

assumptions...

Didn't Neo have a 0W-5 when the lowest grades were xW-20? I recall it wan't much thinner, if any, than a 20.

Yes, yes they did. I believe I brought that up earlier, that 0W-5, not existing in J300, was a serious issue.

 

[ZeeOSix]

assumptions...
Didn't Neo have a 0W-5 when the lowest grades were xW-20? I recall it wan't much thinner, if any, than a 20.

Yes, yes they did. I believe I brought that up earlier, that 0W-5, not existing in J300, was a serious issue.

Was the KV100 of that oil published? Is so, where did it come in w/r to the KV100 grade range for 0W-8? If it came in below the low end of 0W-8 KV100 (below 4.0 cSt), then it's probably why they called it a 0W-5 ... even though SAE J300 doesn't recognize that grade.

 

[Bill7]

Only a multi-million dollar and very controlled study could find the answers to that - like what some oil manufactures do. But based on the science of Tribology and the various controlled studies done in labs and some in real world use conditions, the overall data still points to the fact that thicker oils provide more film thickness and therefore more wear protection. When you throw in all the factors involved like specific oil AF/AW additive formulations, specific engine designs, especially the oiling system and engine component materials, etc, it can get skewed. But when all other factors are held constant (including oil formulation) beside viscosity, it always shows per the basic laws of Tribology that higher viscosity gives more film thickness between moving parts. Wear protection is mitigated by film thickness first, and film strength second.


Nah, no thanks ... we are all watching your experiments.

Google this: HTHS wear graph. This one graph shows engine wear exponentially increases when HTHS < 2.6.
ZeeOSix's explanations of the importance of MOFT (film thickness) further reinforces this.
My believe is that a thicker oil with a higher HTHS up to 3.5 will always offer superior wear protection.

Personally, I only use an oil with HTHS of 3.2 in all my vehicles.
It should protect well if the engine unexpectedly is driven under severe service (extended high heat/high RPM) on a particular trip.

 

[userfriendly]

I have presented all sorts of papers/evidence that off the shelf, modern motor oils labelled as having HTHS of 2.5 or more work well in automotive engines. It does not matter if, in use, there is shear or fuel dilution, they work fine. The thick people seem to say that wear can only be tolerated if the grade is a 40 or more and that they do not care about fuel economy. Fine, then use a 60 grade or thicker oil, as always stated, more MOFT = less wear. I am not denying it although it is not always directly related. And as mentioned in some of the scientific papers, even the investigators argue this point.

For many it must be difficult to understand that 1 nanometer of wear, nor twice that, 2 nanometers is still no wear at all, even though one is twice the wear of the other. 'Never thought it was a difficult concept but apparently it is. It is a political or religious thing I guess. No amount of evidence can convince the other side of anything. Anyway, I think I am pretty much done for now. I did the best I could.

Best wishes,

Ali

Ladies and gentlemen, Elvis has left the building.
Final score
HTHS under 2.6; zero
HTHS over 2.6; 17

"Fine, then use a 60 grade or thicker oil", sounds like sandbox talk.

 

[ZeeOSix]

Google this: HTHS wear graph. This one graph shows engine wear exponentially increases when HTHS < 2.6.
It definitively answers the thick versus thin oil engine wear debate.

Yeah, those graphs have been posted many times ... along with other test information.

Common sense says to use an oil with a protection cushion, so when it temporarily shears due to high heat/high stress,
you still have enough film thickness for protection.

See the first line in my signature, lol.

 

[Bill7]

Yeah, those graphs have been posted many times ... along with other test information.


See the first line in my signature, lol.

I personally want my vehicles to reach 200k/300k/400k miles with zero engine wear/zero oil consumption,
so I use oil with HTHS = 3.2. If my vehicles unexpectedly get severe service during a long trip (like going up long inclines in
slow moving traffic due to an accident up ahead), and engine temperatures are rising, I know my engine wear remains 0 for that trip.
But if I had oil with HTHS = 2.3 in the engine, I would honestly be worried about any severe service causing engine wear.

Note, in the Toyota owner's manuals for cars with ultra thin oil, they admit that for severe service like driving at extended high speeds, that a thicker oil may be more appropriate. That shows that even the engineers realize thin oil can't handle severe service.
So if that is the case, why use thin oil at all, as cars can unexpectedly reach severe service on any trip.

 

[DuckRyder]

I'm not sure why everyone seems so opposed to him carrying out his little experiment at his cost and at risk to his equipment - it'll be interesting and its possible we will learn something in fact it is almost guaranteed we will learn something it just might not be what any of us think.

Why does everyone have to saddle up for the crusades - what is so scary about his thin oil test?

Furthermore he makes valid points - twice nothing is nothing - so at some point the wear does not matter. We always have a lot of hand wringing around here over the best oil and the best filters and so on and so forth, Statements are made that cleaner oil is always better and the higher efficiency filter promotes cleaner oil so the highest effiecny filter must be best. Things are forgotten like you cant filter what the engine doesn't make, but even if we say that's true, does it matter because we have folks like Tegger run a honda to something like 500,000 on Honda filters which are around 65%. Then we have the million mile stories where people did really nothing special except change the oil and filter so it begs the question - does it matter.

Even if HTTS above some magical number creates less wear - will anyone ever realize the benefit of that lower wear number?

 

[chris719]

For many it must be difficult to understand that 1 nanometer of wear, nor twice that, 2 nanometers is still no wear at all, even though one is twice the wear of the other. 'Never thought it was a difficult concept but apparently it is. It is a political or religious thing I guess. No amount of evidence can convince the other side of anything. Anyway, I think I am pretty much done for now. I did the best I could.

What of the many engines that have bore or bearing wear issues? They are design flaws, but using even thinner oils in them may just accelerate the failure. Sometimes it's not just an insignificant number * 2.

I think it's very important to understand the particular engine and its failure modes before experimentation. There are undoubtedly some engines that would be happy on extremely thin oils, but probably not all.

 

[ZeeOSix]

... what is so scary about his thin oil test?

Would you actually use a 0W-5 in one of your vehicles specifying 5W-30? It really seems a lot of people just don't grasp the technical aspects of Tribology and engine wear related to oil and filtration (air and oil), even after multitudes of data and information is posted about. Just because a vehicle "made it" to 500K miles doesn't mean the engine was in the same condition as it would be if different oil and filters were used on it over it's life. Less wear as the engine miles pile up means if can run better and pollute less (more compression, more retained power and fuel economy, less oil burning, etc). That seems to be the part people don't seem to comprehend ... seems they think just because it "seems to still runs good" that it must still be in stellar shape. That's not always the case.

 

[CarbonSteel]

Google this: HTHS wear graph. This one graph shows engine wear exponentially increases when HTHS < 2.6.
ZeeOSix's explanations of the importance of MOFT (film thickness) further reinforces this.
My believe is that a thicker oil with a higher HTHS up to 3.5 will always offer superior wear protection.

Personally, I only use an oil with HTHS of 3.2 in all my vehicles.
It should protect well if the engine unexpectedly is driven under severe service (extended high heat/high RPM) on a particular trip.

I upped the HTHS in my 3.6L from 2.6 to 3.5 for additional protection with zero concern about MPG loss which I see as a fantasy quest for the vast majority of vehicles on the road.

Many driving habits lose the MPG savings between xW-20 and xW>20 within 100 miles of an oil change and in my Wrangler, my right foot or a headwind will erase any MPG savings so it is more than pointless to chase it.

Aside from potentially proving how an engine can fail using too thin of a viscosity, I question what else might be proven.

This is another variation of the same circular argument that has happened in countless threads with nothing proven or disproven.

 

[Bill7]

I know people reach 400k miles on dino 5W-20 oil and low efficiency oil filters (Ex: Ford Crown Victoria taxi's), so it is a valid argument that the wear advantages with higher HTHS oil and high efficiency oil + air filters could be insignificant in the overall scheme of things.

But it's just so hard for me to use a low HTHS oil and low efficiency oil + air filters.
I don't think there is any benefit to thin oils, and there could be significant downside risk.
So, I've chosen to only use HTHS=3.2 oils and high efficiency oil and air filters, so I don't even have to worry about the issue of thin oils at all.

But I am still curious to see what Ali comes up with. I have to admit a part of me wants to see his test results showing high wear metals with low viscosity oil. That would give those of us who prefer higher HTHS + higher MOFT oils closure on this issue.

 

[aquariuscsm]

I too really like Dr Haas' tests. His posts are some of my favorite posts here. It's like Bill7 said, he likes to think outside of the box, as I think a lot of us here do as well. Dr Haas is a very smart man. His posts are always extremely interesting!

 

[ZeeOSix]

I'm interested in seeing his experiments. If I get proven wrong, I'll be the first to admit it.

It won't tell anyone anything unless there is an outright engine failure, or the oil filter keeps getting visible metal debris - which was already detected after the first oil change with only 1000 miles. If there is no blatant detection of engine damage going on, the only "conclusion" in this "test" is that it worked. But in reality, even if "it worked" there will be no way to actually tell if and how much the wear was increased because the monitoring methods to a baseline are not sophisticated enough.

Guys are running 100s of miles on old beater cars on YouTube on WD-40 (search if on YT), and only get them to blow-up after they put a brick on the gas pedal and let the engine bounce off the rev-limiter for 3~4 minutes. If they didn't blow it up on purpose and just drove it for 1000s of mile, the engine wear would certainly be increased from running a lubricant that thin.

 

[ZeeOSix]

I know people reach 400k miles on dino 5W-20 oil and low efficiency oil filters, so it is a valid argument that the wear advantages with higher HTHS oil and high efficiency oil + air filters could be insignificant in the overall scheme of things.

It's about engine condition/health at 400K (or even 100K, 200K) ... not that it just "made it" there. I highly doubt an engine not designed to run on 0W-16 or less is going to be in the same mechanical health/shape as one running xW-30 or xW-40.