Can 0w20 handle high RPMs

[tig1]

Originally Posted by Shannow
Originally Posted by tig1
Scientist also support the theory of evolution but real world evidence says otherwise.


Just Wow to prove a point in the thread......so exactly WHAT is your training in engineering and tribology ??

None.

 

[chainblu]

So, the never ending (and boring) 'thick vs thin' arguments continue. Personally, I think 5w30 vs 5w20 comparisons should be 'thin vs thinner', but I'm still trying to wrap my head around how some of you think 3500 is high rpm.

 

[ChemLabNL]

"It's done for one reason, and one reason only...and the result is entirely satisfactory for the anticipated lifetime of the vehicle."

I dunno, Is it "entirely satisfactory" to have to add a quart of oil in the middle of the OCI because the piston rings are worn?

 

[Bryanccfshr]

An aviation engine is a different animal than an automotive application. Most are aircooled and Not having oil temperature high enough would allow the aircooled heads to cool too fast with rpms and this airflow, that's my guesse but it is an interesting side topic. Since you pointed it thismdirection, the aviation industry as an example, they are an extremely conservative bunch concerning mai tenancy, reliability and safety being number 1. What oil weights do they use in reciprocating aviation engines. Is 20wt adequate?
Originally Posted by ekpolk
Originally Posted by Bryanccfshr
I respectfully will point out as Shanow already has as I slept in my hemisphere that shear and film thickness are different properties than the incompressible nature of liquid and it's behavior in containment.
Yes.

Originally Posted by Bryanccfshr
Liquids pump at the same rate through the pressurized oil circuit to the bearings, nozzles and offices where the oil then does its work.
I'm presently half-way through my RE-training as I return to the flying business. Why are we required to keep our engines at low power until until the oil temperature reaches the "green" range on the oil temp gauge? If you put the power much above 1500 rpm while still cold, you can tell with your ears that, while the oil may be forced to the various "nozzles and orifices", it's not moving through them the same as it does when hot. Yesterday morning (~10C, cold for Vero Beach...) I had to pay for 0.2 hours of extra "flight" time pretty much just waiting for the oil temp needle to hit the "green" range. At least it goes in my log book...

Originally Posted by Bryanccfshr
In the bearings the oil is not only being compressed it is being sheared by a rotating shaft, and there is an outlet for oil to escape. The bearing surface is stationary while the shaft is moving at a high speed in relation to the bearing surface. It begins removing layers of oil and he oil flows outside the bearing as that is the path of least resistance. HTHS is simply the resistance of oil to be stripped away while being incompressible in this situation.. As long as the oil remains in adequate volume the parts remain separated, if the oil shears too quickly then the quality hydrodynamic lubrication regimen is compromised.
Right with you on all that. But doesn't this just prove the point that there's much, much more in play than just "thick vs thin," the lone variable of basic viscosity? While there plainly have been exceptions, the evidence shows that, for the vast majority of applications, the 20 wt oils, under normal proper pressure remain in the bearing spaces and resist being sheared sufficiently to protect as intended?

 

[ekpolk]

Originally Posted by Shannow
Originally Posted by ekpolk
Then as long as there's oil pressure present, a 20wt would protect will always protect just as well as a 30 or a 40 wt -- because it too is a liquid, just like its thicker relatives. ...


No, sorry, in that statement, you are displaying an absolute and fundamental misunderstanding of hydrodynamic lubrication.

A thinner oil will always have a thinner Minimum Oil Film Thickness (MOFT) than a thicker oil all things being considered, and be that much closer to asperite contact.

. . .


No, I get that, seriously. Herein lies one of the problems with those of us who obviously are NOT as well grounded as professional tribologists -- how to correctly articulate the principles, especially when more than one complicated principle is at play, without jumbling them together.

It makes perfect sense that the thinner oil always has the thinner MINIMUM oil film thickness, and with that, comes the increased risk you cite (in knuckle-dragger terminology, metal-on-metal contact, right?). But, and here's the point that I have perhaps "mis-expressed": in the engines for which 20wt oils are "recommended," aren't the operating parameters are such that the oil is rarely* at or below MINIMUM OFT such that damage begins to occur? And though it may be a case of "mixing metaphors" (or being "right" for the wrong reason...), if this is true, aren't the 20s in fact protecting as well as a 30 or 40, if there's no appreciable difference in end result?

If the concepts are getting unduly blurred, please do help straighten them out and keep them in their proper place in the analysis. That's not a snide snipe, by the way. I spend time here because I want to know more about this stuff.

* by "rarely", I mean so infrequently that over the life of the engine and vehicle, we are not seeing shortened engine life that can be blamed upon the "thinner" oil.

 

[PimTac]

Originally Posted by ChemLabNL
"It's done for one reason, and one reason only...and the result is entirely satisfactory for the anticipated lifetime of the vehicle."

I dunno, Is it "entirely satisfactory" to have to add a quart of oil in the middle of the OCI because the piston rings are worn?




There are many factors and reasons for worn piston rings. Oil is not the only blame.

 

[ChemLabNL]

"Pumps being in bypass doesn't matter, as their role is to supply oil to make up for bearing side leakage, the pump isn't to pump oil through the bearings, it's to replenish leakage."

A lot of thinking people have a hard time understanding this.

 

[ChemLabNL]

"The thick oil guys are relying on theory not real world evidence. Scientist also support the theory of evolution but real world evidence says otherwise."

Scientists have always been daunted by Magic and Divine Intervention...We'll get there eventually.

 

[ekpolk]

Originally Posted by ZeeOSix
. . . you would see that if holding all things constant, that increasing the viscosity adds protection due to larger MOFT and typically a higher HTHS.

So yes, there is a difference between the level of protection from using oil as thin as possible for reasons driven by CAFE giving "adequate" protection for benignly driven vehicles vs the level given by using a thicker oil. Put 5w30 in those same vehicles and you get some added protection from the increased viscosity factor, regardless if it's "needed" or not. Why do you think the same vehicles sold in other non-CAFE countries show in the oil recommendation specs going all the way up to 40 or 50 wt is acceptable?


1. Again, if any of these "20-recommended" applications actually require that protection, but didn't have it when they needed it -- we would, by now, have seen the evidence -- a pattern of damage and/or failure -- and we have not...

2. Respectfully "back at you": why do YOU think Toyota is now actually specifying 0w-16 oil in the current Camry (and another model I don't recall right now...)??? Why didn't you mention that too? Gee, before long, 20 and 30wt are going to be the "thick stuff" everyone is nostalgically clinging to.

More seriously, though, your last comment provides an important clue, IMO, about the answer to this whole mess of an "issue": could it possibly be (touch of sarcasm admitted...) that the range of oils that are "acceptable" for most engines is actually quite a bit broader than most might think? I'm reminded of a comment I read long ago, on actual paper somewhere, long before the internet, to the effect that we should use the recommended grade, but it was safe to go "one up or one down." Apart from the few, specific critical applications that obviously do exist, maybe that's been true all along...

 

[ekpolk]

Originally Posted by Bryanccfshr
An aviation engine is a different animal than an automotive application. Most are aircooled and Not having oil temperature high enough would allow the aircooled heads to cool too fast with rpms and this airflow, that's my guesse but it is an interesting side topic.
You can't escape that easily (

)! Lubrication and cooling are different matters (but do have some overlap, of course). And the physical properties and behavior of lubricating oil don't change just because the piston engine in which it is installed is operating above the ground instead of rolling along it. Air cooled engines are vulnerable to abrupt cooling, but that's not an oil-temp issue. We are restricted in how we practice emergency descents for THIS reason. {EDIT: the hot oil stays hot during the plunge, as the cylinders rapidly cool from power-off/excess airflow.} Our maintenance/ops SOP, allow taxiing but not takeoff with low oil temp, out of concern for full, proper oil flow and effective lubrication.

Originally Posted by Bryanccfshr
Since you pointed it thismdirection, the aviation industry as an example, they are an extremely conservative bunch concerning mai tenancy, reliability and safety being number 1. What oil weights do they use in reciprocating aviation engines. Is 20wt adequate?
Of course we don't use 20wt in air-cooled aviation engines. They weren't designed to use it, and the oils involved shoulder a much greater cooling burden than oils in liquid-cooled engines do. In other words, the oil is both lubricant and much more a coolant than in water-cooled engines.

You also hint at a broader concern. I'm not "for" or "against" oils because they are "thin" or "thick". Putting a 50wt aviation piston oil into a 2018 Camry designed for 0w-16 would be about as wise as putting 0w-20 into a carbureted Lycoming air-cooled engine that was always intended to use "heavy" oil. I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."

 

[ekpolk]

Originally Posted by chainblu
So, the never ending (and boring) 'thick vs thin' arguments continue. Personally, I think 5w30 vs 5w20 comparisons should be 'thin vs thinner', but I'm still trying to wrap my head around how some of you think 3500 is high rpm.


Two excellent points. But alas, it sounds like chainblu won't be around to see who takes and keeps the high ground on the head of this pin...

One of the few disappointments I have about the 18 Prius is that the computer won't let the ICE run above 5500 rpm (in the 04, it was only 5000 rpm).* And I thought THESE were low numbers. Maybe I'm more out of touch than I thought.

* The Toyota hybrid cars do not come with tachometers -- the rpm patterns of the engine are apparently deemed too weird for most consumers... I keep a ScanGauge-II hooked to the OBD port and set up on my dash. Good extra info while driving, and it reads codes if and when they come. Very neat tool for geeks like me...

 

[Bryanccfshr]

Where did you come to that extreme conclusion? No one is saying that. What has been said is that a higher rate of decline is considered in making engine oil recommendations using thinner oils. The manufacturer accept the risk based upon their customers usage.


Originally Posted by ekpolk
Originally Posted by Bryanccfshr
An aviation engine is a different animal than an automotive application. Most are aircooled and Not having oil temperature high enough would allow the aircooled heads to cool too fast with rpms and this airflow, that's my guesse but it is an interesting side topic.
You can't escape that easily (

)! Lubrication and cooling are different matters (but do have some overlap, of course). And the physical properties and behavior of lubricating oil don't change just because the piston engine in which it is installed is operating above the ground instead of rolling along it. Air cooled engines are vulnerable to abrupt cooling, but that's not an oil-temp issue. We are restricted in how we practice emergency descents for THIS reason. Our maintenance/ops SOP, allow taxiing but not takeoff with low oil temp, out of concern for full, proper oil flow and effective lubrication.

Originally Posted by Bryanccfshr
Since you pointed it thismdirection, the aviation industry as an example, they are an extremely conservative bunch concerning mai tenancy, reliability and safety being number 1. What oil weights do they use in reciprocating aviation engines. Is 20wt adequate?
Of course we don't use 20wt in air-cooled aviation engines. They weren't designed to use it, and the oils involved shoulder a much greater cooling burden than oils in liquid-cooled engines do. In other words, the oil is both lubricant and much more a coolant than in water-cooled engines.

You also hint at a broader concern. I'm not "for" or "against" oils because they are "thin" or "thick". Putting a 50wt aviation piston oil into a 2018 Camry designed for 0w-16 would be about as wise as putting 0w-20 into a carbureted Lycoming air-cooled engine that was always intended to use "heavy" oil. I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."

 

[ekpolk]

Originally Posted by Hootbro
...
Your written prose is interesting.


Much more interesting is the prose found in my Owner's Manual. So too is the twenty-plus year long absence of evidence that 20wt oils are causing wide-spread damage to the engines in which they are used.

Surely, now that Toyota (Mazda in Japan too, IIRC) is beginning to recomend 0w-16, we'll start seeing the junk yards filling up with engines killed by "thin" oil. . .

 

[PimTac]

"What has been said is that a higher rate of decline is considered in making engine oil recommendations using thinner oils. The manufacturer accept the risk based upon their customers usage."





How much of a decline is my question and it may not be answerable. If a engine is expected to last 300,000 miles on 5w30 but only lasts 280,000 on 0w20 then do we blame the oil at that point? There are too many factors involved to only point fingers at the oil.

 

[Jimmy_Russells]

Originally Posted by y_p_w
Originally Posted by ekpolk
And this brings me back to the question I've posed several times, and none of the "thicker is better" advocates have answered: "where are all the vehicles ruined by 20wt oils in the twenty-plus years that car makers have been specifying them?" Again, not the individual special cases, but the overall mass of cars that certainly would have accumulated by now, were the 20s not up to the task. There would be a mixed mass of failures, Accords, Tauruses, Camrys, Civics, all "dying" in mass as they all were damaged over the years by "inferior" 20wt oil. This just hasn't happened.

Sure. There have been cases, but mostly they've been oil sludge cases like the Honda VCM system that would likely have cooked "conventional" 5w30 too. There have been sludge monsters where 5w30 was spec'ed, including Saturns and Toyota 3.0L V6s.

Still - many of the newer cars these days seem to specify 0W-20 motor oil. I was looking at a Honda Civic Type R, which seems to be doing it a different way than the old way Honda did it. Instead of 8000-9000 RPM redlines they're doing it with a turbo and lots of boost. Somehow they're willing to warranty a 306 HP 2.0L turbo 4 for 5 years and 60K miles using 0W-20 and an oil life monitor. Of course that has an oil cooler to help keep the oil temps down.

It may not be the same as doing hot laps around a track, but most warranties won't cover that.


Honda is actually providing warranty on that car for track use. I'm not sure however if there's a stipulation in the owner's manual to use thicker oil if doing so.

 

[ekpolk]

Originally Posted by Bryanccfshr
Where did you come to that extreme conclusion? No one is saying that. What has been said is that a higher rate of decline is considered in making engine oil recommendations using thinner oils. The manufacturer accept the risk based upon their customers usage.


Originally Posted by ekpolk
. . . I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."



I assume this is what you're reading as "extreme." I may have stated the point with some hyperbole for emphasis, but is this not what's going on? Car makers recommend 20wt, or even 16wt oil for a whole range of models, and have for twenty years. And while it is clear that there are some specific applications where that has proven inadequate, for the most part, it has proven safe and effective, and millions of cars run on 20wt to the end of their useful life, without failing because of using "thin" oil. Yet the doubts persist, and yes, one poster here even suggested I should ignore my OM and use 30wt to get "better protection." BTW, he didn't define "better"...

There may or may not be an actual "higher rate of decline" in one particular engine or another (I doubt any mfr will share that info), or it may be theoretical. How can we even know? Personally, IMO I'm not convinced that the small increased wear is happening in every design. But if it is, it's so miniscule that it has no bearing (sorry...) on the ultimate outcome, then how is it a real concern?

 

[PimTac]

Then there is this.


https://www.oreillyauto.com/detail/...t-0w-8-synthetic-motor-oil/xpr08/5699067

 

[ekpolk]

Originally Posted by PimTac
How much of a decline is my question and it may not be answerable. If a engine is expected to last 300,000 miles on 5w30 but only lasts 280,000 on 0w20 then do we blame the oil at that point? There are too many factors involved to only point fingers at the oil.


You get the "Hits Nail on Head" Award for the day.

Or, what if there are enough cold starts in the mix that the "300,000 mile on 30wt" engine actually goes to 320,000 miles on the 0w-20? Perish the thought. . . There's that $^#& sarasm again...

 

[dareo]

For whatever its worth the only time i've seen an engine fail on a 20 weight was a Toyota 4AGE 20 valve being rallied. It already had a ton of abusive miles on it and the owner liked 5w20 for winter street use, ended up taking it to a rally cross in the spring and it threw a rod. Was it the engine's time to go? Or was it the oil? This thing would rev to nearly 8,000 and was never spec'd a 20 weight.

 

[ekpolk]

Originally Posted by PimTac
Then there is this.
https://www.oreillyauto.com/detail/...t-0w-8-synthetic-motor-oil/xpr08/5699067


0w-8!!! Oh pleeeeeeaze, just stop!!! This will go on for another twenty years! But by then, the argument will transmogrify into something like, "listen, I'll never be caught putting anything thinner than a good thick 5w-20 into my . . ." well you know the rest.

You have to admit, whatever you believe, that "eight weight" rolls off the tongue nicely.