Another "Taxi" Study: Relationship of Engine Bearing Wear and Oil Rheology 872128
- Thread starter AEHaas
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Everyone can ask themselves do they want "adequate" versus "optimal" protection.All that's needed for you ... not necessarily "needed" for all. And how do you know just being "adequate" enough is actually providing the same level of engine wear protection? Like mentioned in this thread, Ford thought 5W-20 was "adequate" for a long time in some of their engines, but seems they've changed their minds on that. But hey, if it's "adequate" for you, that's all that matters ... but it may not be "adequate" enough for others that want some more engine protection, just like Bill7 mentioned. And what he said is true based on the science of Tribology. Nobody can prove that increased HTHS does not give more MOFT, which in turn gives more wear protection. The people who want that do what it takes to achieve that ... go a bit thicker, since "adequate" enough isn't always good enough.
ZeeOSix and I want "optimal" protection.
CR94 and PimTac may want "adequate" protection.
AEHAUS may prefer to be a pioneer pushing the boundaries of low viscosity oil.
Each of us can get the type of protection we want.
More like "ample." Have you ever looked at my signature? Maintaining adequate MOFT "headroom" in engine bearings is the least of my automotive worries.
Did it ever occur to you that one engine might have more MOFT "headroom" on xW-20 than a more highly stressed, hotter-running one does on xW-30? Even at equal temperature, the difference in minimum required HTHS viscosity is only about 9%.
That's right, and it's the reason I use xW40s in xW30 and xW20 engines.
Lots of headroom and an extra layer of protection make the wheels go round and round.
Wow, that's interesting, using xW40's in engines meant for xW20.
Kind of like the opposite strategy that AEHAUS is using.
Would be interesting to do some UOA analysis on going 2 grades thicker.
It would not show a comparative wear between those two grades. As has been pointed out here multiple times.
The only thing that UOAs have shown me on my personal vehicles, is that I don't need to do UOAs on personal vehicles.
The xW20 engines that I put xW40 in were only xW20 in the USA and Canada and xW30 elsewhere.
Other factors I considered were the duty cycles of the vehicles and how they were driven.
If the cars were to be used only for trips to the liquor store for a bottle of Jack Denials, a pack of smokes and a lotto ticket, then xW20 would provide "adequate" protection, but would be of no benefit over the thicker oil. These vehicles would or could see "extreme" conditions. I wanterd to provide them with an extra layer of protection and headroom in the MOFT department.
Add me to the optimal protection list. Adequate never cut it in my book for anything.
Sounds like a smart idea. In my opinion, extra protection is preferable to "adequate" protection.
Since their same engine is likely speced for xW-30 or XW-40 in Europe and Australia,
I can't understand why people choose adequate protection (what advantages do they see in getting adequate protection)?
Welcome to the 'optimal' protection club demarpaint.Add me to the optimal protection list. Adequate never cut it in my book for anything.
I'm glad to be a member.
I don't know enough about Uganda to answer that question.
But since Uganda doesn't have CAFE laws, I would think recommended viscosities in that country would be similar to Europe/Australia.
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I’m surprised you don’t know since searching for tangents to verify your bias is the thing here.
Engines have changed despite all the naysayers here. Things do evolve. But go ahead and stick with your bias.
Please Google HTHS wear graph.
HTHS wear graph's show exponential engine wear once HTHS goes below 2.6 (which is where new 20 weight oil starts out).
Those of us who want optimal protection put greater emphasis on HTHS and MOFT (film thickness).
HTHS and MOFT are not a tangent. They are central to all discussions on engine protection..
It's helpful not to think about oil in terms of xW-20, xW-30, xW-40.
Instead compare the HTHS of various oils, and choose one that has a HTHS over 3.0, ideally close to 3.5.
Funny you should ask that. I found a photo of the same engine in a car with its hood open at a SA Toyota dealership and the oil cap had 15W40 on it. I would imagine that Kenya, the Ivory Coast and Uganda have the same.
I bet that cap has a part number.
Who was the last King of Scotland?
Right. Shannow invented the XW/HTHS grade. Pick your winter grade and desired HTHS. All that is in between, is not important.
But the physics of Tribology doesn't change, and viscosity in general, and HTHS viscosiy in specific conditions, will always be the main factor that keeps rubbing parts separated better. Better separation of moving parts always means less wear when other factors are constant. It's been that way since lubrication was invented, and will always be that way because the physics of Tribology never change. Still waiting for the science showing that less viscosity gives more MOFT between moving parts.
It's been mentioned many times why engines running 0W-16 or less need special engine design changes. Because the physics of Tribology says so, lol
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Exactly. Well said. The physics of Tribology can never change.
Thin oils lack a high enough HTHS and MOFT (film thickness).
The solution thin oil uses (like 0W-16) is too dependent on additives (film strength only).
The strategy of 0W-16 is: Allow some metal on metal contact, and rely on the additives to mitigate the wear.
A better solution is to have a high enough HTHS and MOFT (film thickness) to prevent metal on metal contact in the first place.
This difference in wear between thin and thick oil protection might surface in oil consumption later on in the engine's life
when the cumulative effects of relying on the additive package to mitigate metal on metal wear will add up enough so that when
an engine gets high mileage, the oil consumption will keep increasing. In my opinion, it's better to use oil with a higher HTHS, MOFT
from the beginning.
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