If 0w-20 in the winter why not 5w30 in the summer

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Originally Posted By: JoelB
The problem is that people still assume a thicker oil provides better wear protection. Which I have never seen a shred of conclusive proof for that.


http://papers.sae.org/922342/
The relationship between viscosity and engine performance


monograde paper showing other variables at play
http://papers.sae.org/810330/
The relationship between viscosity and engine performance part 2

edit, ooops, and forgot
https://bobistheoilguy.com/forums/ubbthreads.php/topics/1036066/1
 
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I had to quickly skim your links as i don't have a ton of time so apologies if i got this wrong. But it seems like the first link is a test done on only the bearing itself (at least the page it immediately brings me to), the second is done on a small single cylinder engine, and the final link is just a graph. I would hardly say that those are apples to apples comparisons to a multi-cylinder modern car engine under the inconsistent daily driver conditions.
 
OK, so in order to be a "shred of evidence", it's got to meet your preconceptions of "evidence".

OK, how does a single cyliner test engine big end get invalidated by only having one cylinder.

In an engineering sense please...
 
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Originally Posted By: userfriendly
Yeah I know. They are like the pop-up gopher game at the state country fair. Hit one with a hammer and six more pop up.

lol.gif
 
Some time ago i remember a statement that was posted but i don't remember who the OP was. Some of the older members may remember, but it did have somewhat of a profound impact on my thinking and i still think about it when choosing an oil viscosity. It was stated as: As thick as necessary as thin as possible. Think about it!
 
Originally Posted By: 4ever4d
Some time ago i remember a statement that was posted but i don't remember who the OP was. Some of the older members may remember, but it did have somewhat of a profound impact on my thinking and i still think about it when choosing an oil viscosity. It was stated as: As thick as necessary as thin as possible. Think about it!


I remember the guy, also recommended running the thinnest oil in the manual, e.g. his ex girlfriend's datsun 510 "which specified 5W20 back in the 60s"...it did, but only up to 18F max temp.

The premise, though, is fine.

From an engineering perspective, viscosity keeps things apart...in bearing surfaces, that's traditionally (like old old traditional) called the "zero wear" regime, where the film thickness is such that parts never contact...not every part in an engine lives there, and it's a lot of wasted energy.

That's why many of the papers show additiveless oils produce less wear with thicker oils.

Drop the viscosity, drop the film thickness, and start heading towards mixed, boundary, EHD, and you are in an additive controlled regime, with "acceptable wear" as the target...you have to replace the film thickness with additives...many of those additives "control wear rates' as opposed to eliminating.

Doesn't mean, and I would never say that the OEM recommendations will create a "pile of failed engines" along the highway, NOR provide (in)adequate life (Honda's words) for an average consumer...

If you save a couple hundred dollars gas before you throw your car out anyway, it could well have been worht it.
 
The redheaded oem lady said in her F&L presentation, every engine has an appetite for a particular oil grade and not all respond the same to thinner grades.
Meaning fuel economy could be worse with 0W20 than with 5W30 in engine A, and better in engine B.

In the HD side of the coin, engines are expected to last 10s of thousands of hours or well over a million miles in otr applications.
Unlike light trucks and passenger cars that fall apart around the drive train, or age-out, HDs will not trade fuel economy for increased wear.

For now, 0w30, 5w30 CK-4s and FA-4 10w30 is as light an engine oil as your going to see with its HTHS limit of 3.10.

Improved fuel economy in passenger PCMOs, should be referenced to 5W30 and not 20W30, a non FM'd or VII'd mono-grade as the case is now.
 
I have a saying: As thin as necessary as thick as possible.

Thicker oil means more protection, period. You want as thick as possible. But thin enough for startup when cold in your ambient temperature range.
 
Shannow, while I would agree that those articles are evidence of thicker oils being beneficial they are in no way conclusive. There are cases where a thin oil with perform better, and others where a thick oil will perform better (speaking specifically for cars and trucks not driven for business purposes). My main point is that we shouldn't assume that either thick or thin is better every time no matter what, which seems to be a common thing around here.
 
Originally Posted By: JoelB
Shannow, while I would agree that those articles are evidence of thicker oils being beneficial they are in no way conclusive. There are cases where a thin oil with perform better,


Cool, for the sakes of discussion, would you mind sharing the links ?
 
Originally Posted By: Shannow
Originally Posted By: JoelB
Shannow, while I would agree that those articles are evidence of thicker oils being beneficial they are in no way conclusive. There are cases where a thin oil with perform better,


Cool, for the sakes of discussion, would you mind sharing the links ?


Because thinner oils will flow to the upper end faster than thick oils in very cold temps.

https://www.youtube.com/watch?v=OWiQyR7PWII
 
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Did you want me to dig up some abstract SAE papers and graphs? The proof is that millions of vehicles run on these "thin" oils and last as long as the average consumer needs them to. There are users here with over 250k miles on motors running 0w20. It may not prove that thin is better than thick, but it does prove that "thin" oils are totally acceptable in a daily driver.
 
Originally Posted By: tig1
Because thinner oils will flow to the upper end faster than thick oils in very cold temps.


How cold ?

And, as per all of our previous discussions it's the "W", pumpability rating, at the limits of pumpability...

(This is where you bring in the Esso videos usually, so I'll save you the trouble)



Note, it's the "W" rating, used where the "W" rating is inappropriate for the temperatures in the cold box that PROVE...that at extremes of cold temperature pumpability, that you need a pumpable oil...
 
Originally Posted By: JoelB
Shannow, while I would agree that those articles are evidence of thicker oils being beneficial they are in no way conclusive.

Thicker oil being beneficial in thicker oil film thickness and better/stronger metal wear protection is part of Laws of Physics.
How could a Law of Physics be not conclusive ?


Quote:
There are cases where a thin oil with perform better, and others where a thick oil will perform better (speaking specifically for cars and trucks not driven for business purposes).

I'm not disagreeing with you, but could you quote a Law of Physics that supports/proves thin oil performs better in wear protection?

Edit:correctum
 
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But, is that thicker oil film really required? I'm not saying go down a grade and run the thinnest oil you can, I'm a stickler about OE recommended oil weights. People just seem to fear 20wt oils and always want to go heavier.

I can't imagine throwing a 20w60 oil in my versa (which takes 5w30) will make it last forever.
 
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Originally Posted By: tig1
Because thinner oils will flow to the upper end faster than thick oils in very cold temps.

Tig, how many -35 C to -40 C (and colder) starts have you done? I've done more than a few, but starting at the limits is a lot different than simply a "cold start," as in the oil being simply at a sensible ambient temperature that is above CCS and MRV limits for the oils in question. 32 F, for instance, is immaterial to any PCMO, even a monograde.
 
Let me rephrase that a little. There are many things that contribute to that MOFT, one of which is intial static viscosity, but that is a minor part of the equation. That is why these oils keep getting lower in viscosity. Because they can. There are other ways to control MOFT and dymnamic viscosity, ex. such as increasing oil pressure. I f the oil did not have to do other things, we could use an air bearing, which has an even lower viscosity
Throw another quart of air in willya?
 
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