Optimal kinematic viscosity for mimimal wear?

[SuperBusa]

Originally Posted By: BuickGN
It's a fact that thicker oil will keep parts separated better in a journal bearing.


Isn't there an industry standard oil test that determines the film strength of oils? It makes sense that the oils that have the higher film strength would correlate to a higher viscosity, and would protect two sliding surfaces better than an oil with a weak film strength.

The oil pressure in an engine really doesn't provide enough force to "float" a journal bearing. All the oil pump pressure really does is deliver an adequate flow volume to the parts to keep them well lubed.

 

[Gary Allan]

Well, don't get all excited. We're not going to write or rewrite history or physics here.

Sure, heavier oils keep bearings further apart. I won't argue with that since a journal bearing thread a bit back. But I keep ..in just thinking out loud ....SO? That means that the heavier oil has more tolerance to visc alterations due to temperature changes before the asperities meet up. It can move at a lower volume through the bearing since it will be closer to acceptable viscosity during the trip.

..but I don't see where just having a thin oil dictates that you'll have contact .nor that the visc will change enough to present issues.

..but, not to overuse the statement, just where do you think all the tired motors are that should be showing signs of fatigue? I mean ..really? They can't all be exceptions to the rules.

 

[SuperBusa]

Originally Posted By: ekpolk
First off, a couple of papers published by the SAE do not constitute "proof" at all.

Hey, the cigarette companies have backed the publication of a bazillion papers showing all sorts of neat things, like smoking is not addictive, and does not cause cancer at all. I guess those things are "proven" too...

... this stuff is getting nuts. I think I'd take more stock in the SAE papers then a hundred different "theories" from chat board members on what's really going on in a journal bearing with different oil viscosities.

Besides, the SAE has nothing to gain about "tweaking data" like the cig companies do. What does the SAE sell? ... what do cig companies sell?

Obviously, the thinner oils still have enough film strength to protect Aunt Bea's 4 banger Corrola (which was designed to use thinner oil) while going back and forth to church and the bingo hall. But ol' drag master Jack isn't gonna like using Aunt Bea's oil in his top fuel dragster.

 

[Bryanccfshr]

Originally Posted By: BuickGN
Originally Posted By: Gary Allan
Originally Posted By: OVERK1LL
Originally Posted By: Gary Allan
OVERKILL ..can you show me one study that Doug has done on a Ford Escort with a low compression 1.9 engine living a normal life? Honda Civic? Geo Metro? Prius?

Every instance that I can recall, Doug has been on the leading edge of high performance R&D and HEAVY DUTY R&D.

When have you heard him comment on something that didn't spec AT LEAST a 40 grade from the OEM?

This is not at all meant to discount anything Doug says ..since I'm absolutely sure that it's GOLD ..but there's is a whole lot I've never seen him say (I can't hear him, but I can imagine it) ..since ..to tell you the truth, it's of no interest to him. I've never heard him comment on the mundane. That's just about our entire existence for most of us.



We talked about my Expedition. There's a thread on it here somewhere.



I'm glad he gave a token mention to a light weight oiled engine

This has been fun, as usual - in a +/- way

I would never argue with XS650 ...Doug Hillary ...and someone like Shannow. They're too smart. The only trump card that anyone in the lighter persuasion camp has ..perhaps it's more of a rhetorical trick up their sleeve, is that we're waiting with anticipation for the legions of grenaded and tired 20 weight engine to show up. Those who have been waiting ..well, they've been waiting.

It's kinda like Poole and Bowman pulling the control module from the main antenna array on Discovery due to HAL's 100% flawless determination that it was going to fail in xxhours. Poole and Bowman find nothing wrong with the thing.

We never got to see that test played out ..


Anyway ..since we're not seeing all these grenaded and degraded engines .........AND the physics are allegedly immutable ..the conditions of the real world testing MUST be different than normal givens. That is, assumed conditions just aren't realistic or factual.


Is that really all you guys have, the lack of grenaded engines? No one can answer Rickey's question because the answer goes against the thinner is better. It's a fact that thicker oil will keep parts separated better in a journal bearing. I don't even want to be a part of this thread it's so retarded. We come up with new facts and proof all the time and every time there's a point being made, you guys go back to the good old "where are all the grenaded 20wt engines?" I see bait after bait being thrown out there and I see people arguing even though they're clearly wrong just to win an argument. I bet if I asked what color the sky was one of you guys would say red just do disagree. I quoted Gary on accident, this isn't just aimed at him.


BGN, Yes a thicker oil will maintain a thicker lubricating wedge in a journal bearing. I don't think the discussion is framed right. Lubrication is a balancing act. I don't think any viscosity is superior. It is just a tool like a wrench, and the engine is the nut. You want to match them but often it is not an exact fit with lubricants so there is tolerance for differnce. That's why so many engines can run on 5w20 or 5w40 oil..There are trades offs.
5w20 in engines designed as low fricction forms an oil wedge that keeps the parts seperated. The film thickness is not as thick as a 5w40 meaning a particle going through the bearing could clear with a 5w40 and not the 5w20. Fortuantely we have pretty good air filter and oil filter systems that are a lot tighter than they used to be. That combined with fuel injuction that used to dilute the oil in carbbed engines allowed the industry to take advantage of the 20 wts on a wide scale.

In Summary I believe in and use 5w20's. I have not seen any indication that it provides inadequate lubrication. The main sell to me was a 3 or 4 years back when I got a WILD are and went from a 5w40 to a 5w20 in a 4 cylinder engine that allowed either...The engines response was noticable enough that I became a believer in thinner oils. I was a really hard headed thick head prior to that.
Now I have settled on one factor. Use Automaker recomendations in the market you are in. I allow myself one deviation out of economic convenience, energy conserving oils are pretty interchangable and soi I will run 5w30 and 10w30 in by 5w20 jeep becasue it was on sale and in the manual tranny low rpm high low situations I will test for measurable differnces in these grades.. This is a trend you may want to peek into the UOA forum now and then to see how it is working out as I will be running 5w30, 10w30 5w30 and then again 5w20 in the same engine and tracking it.

There is no blanket best but to try to find the best for an out of norm situation one must be open to solutions and set aside our personal viscosity dogma to get to the best solution.

 

[Peted]

Originally Posted By: SuperBusa
Originally Posted By: ekpolk
First off, a couple of papers published by the SAE do not constitute "proof" at all.

Hey, the cigarette companies have backed the publication of a bazillion papers showing all sorts of neat things, like smoking is not addictive, and does not cause cancer at all. I guess those things are "proven" too...

... this stuff is getting nuts. I think I'd take more stock in the SAE papers then a hundred different "theories" from chat board members on what's really going on in a journal bearing with different oil viscosities.

Besides, the SAE has nothing to gain about "tweaking data" like the cig companies do. What does the SAE sell? ... what do cig companies sell?

Obviously, the thinner oils still have enough film strength to protect Aunt Bea's 4 banger Corrola (which was designed to use thinner oil) while going back and forth to church and the bingo hall. But ol' drag master Jack isn't gonna like using Aunt Bea's oil in his top fuel dragster.


Same as I have been saying. The thin oils may be suitable for the camry mall cruiser, but not for more high performance applications.

Also, the argument that if thin oil destroyed engines, then there would be many modern cars in the junk yards is getting quite old. No ONE is saying that thin oils destroy engines. Only that thin oils may not be providing the best protection...

It isn't that complicated.. But obviously, for some, it is.

 

[Bryanccfshr]

I agree so long as you leave testostorone and ego at the door when defining your application. For most of us whare recomended 5w20 is perfectly adequate and there is no gain from going any thicker.
I am afraid with the granny analogies many think that running 5w20 is not tough. The fleet of Ford Trucks running it in the oilfields seem to kick that vision. Americans are known to base much of their identity on their vehicles/ Not trying to get personal just describing human (male) nature that can influewnce our views.

 

[FZ1]

What's the "best protection"? Running a thicker,higher friction oil which causes your engine and trans to run at higher temperature;or running a thinner,lower friction oil which allows your engine and trans to run at cooler temperature? Pay your money and take your choice. I'm runnin' a 5-20 synthetic down here.

 

[Audi Junkie]

I'm considering 5w-20 for my mom's VW 2.0 that sees only short trips. Thankfully it does not burn oil, so I may try it.

 

[SuperBusa]

Personally, I would not try a 0w-20 or 5w-20 if the manufacture didn't list it as an option. Hopefully, people are not switching to something not recommended by the manufacture ... as there may be specific design reasons why they spec a certain viscosity.

 

[CATERHAM]

Originally Posted By: Rickey
And I will agree that some engines will do just fine on an 8Cst @100C product and some require a much thicker product.
Consider that the 8cst product will likely damage the engine requiring a 16Cst product and the contrary is not true.
Yes viscosity matters and too much within reason is far better than not enough.

So there issue settled.
Or carry on as you wish!


Sorry, but I beg to differ. I'd posit that no modern engine, be it an Enzo Ferrari or M series BMW requires a 16 cSt @ 100C oil.
The mfr spec's a 50 or 60 wt oil to provide adequate vis when oil temp's may hit 300F on the track. And it is usually only on the track where you can use enough WOT over a given period of time to build up those kind of temp's in the oil.
That's why Dr. Haas can run a 20 wt oil in his 600 plus hp Enzo; he simply never see's oil temp's above 180F on the street in Florida.

 

[ekpolk]

Originally Posted By: SuperBusa
Originally Posted By: ekpolk
First off, a couple of papers published by the SAE do not constitute "proof" at all.

Hey, the cigarette companies have backed the publication of a bazillion papers showing all sorts of neat things, like smoking is not addictive, and does not cause cancer at all. I guess those things are "proven" too...

... this stuff is getting nuts. I think I'd take more stock in the SAE papers then a hundred different "theories" from chat board members on what's really going on in a journal bearing with different oil viscosities.

Besides, the SAE has nothing to gain about "tweaking data" like the cig companies do. What does the SAE sell? ... what do cig companies sell?

Obviously, the thinner oils still have enough film strength to protect Aunt Bea's 4 banger Corrola (which was designed to use thinner oil) while going back and forth to church and the bingo hall. But ol' drag master Jack isn't gonna like using Aunt Bea's oil in his top fuel dragster.


What's that old saying about throwing stones and glass houses. . . Ummmm, in case you didn't notice, the SAE doesn't write the papers. Various authors or groups of authors do. But most fundamentally, you totally missed my point. One "study," whatever it says, doesn't (except perhaps in an extreme) constitute conclusive proof of the proposition(s) involved. This is true whether we're talking about oiling a bearing, treating a disease, trying to understand a supernova, or whatever.

 

[ekpolk]

Originally Posted By: SuperBusa
. . .
Obviously, the thinner oils still have enough film strength to protect Aunt Bea's 4 banger Corrola (which was designed to use thinner oil) while going back and forth to church and the bingo hall. But ol' drag master Jack isn't gonna like using Aunt Bea's oil in his top fuel dragster.

Oh I forgot this gem. Please show me where any of us who don't see "thin" oils as some form of evil have ever suggested that someone should run 0w-20 in a top fuel dragster. Let's keep it real now. . .

 

[Sayjac]

Originally Posted By: peterdes
. Some people are just too stubborn... Those people are ignorant.
On that single point in this discussion, I can agree sir, that you speak authoritatively.

 

[Steve S]

Originally Posted By: Gary Allan
Quote:
I don't think over the road trucks are operated at near maximum loads. The good drivers even when going up hills gear for minimum load on the engine otherwise the turbos will get too hot.


Would you buy a tri-axle dump only to put 5yrds of dirt in it and tool around the countryside? Would you buy a Class 8 rig and only load it to 20k. Would you waste the money. How about a bulldozer or a loader ..and only use them to 10% capacity?

No, you wouldn't. We drive cars and ..by gosh ..even pickup trucks way below their sensible limits.

Please ..(sigh) ..oh, never mind.
Gary you are not really getting this post Since I have enough experience ,since I owned a semi for several years running coast to coast in these lower 48 states .I can with authority there is NO over the road truck and I would bet any aircraft that ever operates constantly at or near maximnm engine loads. Reread the original post. If interested My neighbor is an ex Marine fighter jock and now drives a commercial jet for a major airline about planes operation as it pertains to operating an maximum engine output.

 

[ekpolk]

Originally Posted By: peterdes
. . .

Same as I have been saying. The thin oils may be suitable for the camry mall cruiser, but not for more high performance applications.

So tell me, before this gets away: exactly why do you feel the need to use pejorative terms like "camry mall cruiser" in your argument. Could it be that, having no solid factual basis, you feel the need to resort to name-calling instead?

If, by "high performance application" you mean engines involved in some form of racing, then sure. As I've been saying all along, you have to look at the specifics of the situation. For the vast majority of street cars, be they Camrys, Tauri, Accords, Mustangs, or whatever, a 20 wt oil is providing optimal lubrication. A top fuel dragster is a totally different animal. If you want to consider different animals, consider for example, Mobil Jet Engine oil -- which weighs in at about 5 cSt -- and where are all the jet engines that must be coming apart? I hesitated to offer that example, because I know it will get all of you hootin' and hollerin' that it's not a fair comparison, and you know what -- it isn't. But in like fashion, comparing a top fuel dragster (or virtually any car that's only a racer), to any street car, is similarly not a fair comparison.

Originally Posted By: peterdes
Also, the argument that if thin oil destroyed engines, then there would be many modern cars in the junk yards is getting quite old.

It's getting "old" for you because you simply have no good answer for it, and it simply doesn't square with your opinions that you wish were facts, and that you want to hold on to. You will continue to hear this point until someone proves (not with "one-zee" and "two-zee" anecdotes) that there actually is damage being done. Not destruction, just damage.

Originally Posted By: peterdes
No ONE is saying that thin oils destroy engines. Only that thin oils may not be providing the best protection...

First off, well yes, many of you have said that. Go back and review the evolution of the thick-thin threads. At first, for many, it was all about destruction. As recent history has proven this to be wrong, it has slowly shifted to "optimum lubrication". Perhaps true for some applications, but I'm confident that as time marches along, we'll see that for most modern engines, lighter oils actually are a better overall solution.

And finally, you simply can't have it both ways. Either the oil is protecting the engine, or it's not. Now the syrup worshipers are suggesting, through the "not optimal" theory that some damage is being done, but that damage conveniently escapes all the normal means of measuring such. If 20 wt oils were actually causing more wear in engines, then we would see at least some objective indicators, such as lead and iron, etc., consistently being elevated above comparable cars using heavier oils. But we're not... Most of the studies are tantalizing (in both directions), but they simply don't tell us what's happening in the bearings of an average, street-use Accord or Taurus.

Originally Posted By: peterdes
It isn't that complicated.. But obviously, for some, it is.
If you're wondering who "some" might be, check a mirror.

 

[ekpolk]

Allright, let's try to get this back to some form of specific discussion, and not the sweeping generalities that have been filling up the last few pages.

So, let's rephrase the question. What do you all think is the "optimal" kinematic vis for a specific engine in a specific usage. If we can agree upon nothing else, I'm sure we can agree that "optimum" kinematic vis (and let's make it at op temps) is not the same for BGN's old turbocharged Grand National and a brand new V-6 Honda Accord.

I'll start. Take my Camry Hybrid. It's driven roughly half-and-half city and highway. I don't baby the car at all. The manual calls for 0w-20 ("preferred") or 5w-20, but permits the use of unspecified heavier viscosities. I'm going with the 0w-20 (though remain open to change, based upon future UOA). The engine is clean and tight, and runs beautifully on 0w-20. I rarely see coolant temps rise above 200F, and most normally hovering around 190F (highest seen ever is 207F per ScanGauge-II). My laser/IR temp gun has never read above 185F when shot against the bottom of the oil pan (which is black painted stamped steel). And this is in FL in the summer. Hey, it's just a cool running engine that even when driven hard, does not seem to get hot. I see 6k rpms a minimum of a half-dozen times a day (often more...) screaming up the interstate on-ramps I use every day. I often do WOT passing on country highways (FL rte 20 for those who know the area). But the engine always stays cool.

What possible benefit would there be in my using a higher vis oil? Since every indicator I have is that this is a very cool-running engine (I suspect Toyota leans this way after that little sludge thing with hot 1MZ and 5S engines...). I strongly suspect my actual running viscosity is pretty close to what's seen with typical 30s in hotter running engines. I just don't see any harm in using a 20 in this engine, and thicker oils just cause me to burn more gas.

 

[BuickGN]

Originally Posted By: ekpolk
Allright, let's try to get this back to some form of specific discussion, and not the sweeping generalities that have been filling up the last few pages.

So, let's rephrase the question. What do you all think is the "optimal" kinematic vis for a specific engine in a specific usage. If we can agree upon nothing else, I'm sure we can agree that "optimum" kinematic vis (and let's make it at op temps) is not the same for BGN's old turbocharged Grand National and a brand new V-6 Honda Accord.

I'll start. Take my Camry Hybrid. It's driven roughly half-and-half city and highway. I don't baby the car at all. The manual calls for 0w-20 ("preferred") or 5w-20, but permits the use of unspecified heavier viscosities. I'm going with the 0w-20 (though remain open to change, based upon future UOA). The engine is clean and tight, and runs beautifully on 0w-20. I rarely see coolant temps rise above 200F, and most normally hovering around 190F (highest seen ever is 207F per ScanGauge-II). My laser/IR temp gun has never read above 185F when shot against the bottom of the oil pan (which is black painted stamped steel). And this is in FL in the summer. Hey, it's just a cool running engine that even when driven hard, does not seem to get hot. I see 6k rpms a minimum of a half-dozen times a day (often more...) screaming up the interstate on-ramps I use every day. I often do WOT passing on country highways (FL rte 20 for those who know the area). But the engine always stays cool.

What possible benefit would there be in my using a higher vis oil? Since every indicator I have is that this is a very cool-running engine (I suspect Toyota leans this way after that little sludge thing with hot 1MZ and 5S engines...). I strongly suspect my actual running viscosity is pretty close to what's seen with typical 30s in hotter running engines. I just don't see any harm in using a 20 in this engine, and thicker oils just cause me to burn more gas.

You called my TL a V6 Accord! How dare you lol.

A couple points. The TL is opeated in a hot climate and winters rarely see freezing. I'm not running anything thicker than someone in Canada running a 20wt. I would have no problem running a quality 20wt like Redline but I'm not just so I can say I told you so when it has 300,000 miles on it.

The GN as I've said runs stockish bearing clearances which just happen to be the same as many 2009 model cars. Oil temps rarely see 200 degrees. I run it hard for short bursts and it has a large oil cooler. It's an extreme example I know, but it shows that thick oils are sometimes needed even with relatively tight clearances.

 

[FZ1]

I agree. I want to run the thinnest oem spec'd oil for quicker flo and lower temp tendancies. My starting point is,therefore, the oem spec 5-20 for my 02 V6 Accord. My Accord has 99,000 miles and half of that is towing my little 700 lb. Bass Boat. I run a middle weight 5-20 (PP). I wanted to top up a couple of the remaining ounces in my $20,5 quart, jug to refresh the fill after 4 months and 3,000 miles,but,dadgum boys,it was still on the "Full" mark.

 

[ekpolk]

Originally Posted By: BuickGN
. . .

You called my TL a V6 Accord! How dare you lol.
As warped as it sounds, I actually wasn't thinking of the TL! Really. Maybe it was some form of sub-conscious mental slip...

Actually, I was trying to think of the least stressful, most modern app. I figured a Honda V-6 would be close to fitting that bill. But yeah, now that you mention it, that's genetically pretty close to the TL...

Originally Posted By: BGN
A couple points. The TL is opeated in a hot climate and winters rarely see freezing. I'm not running anything thicker than someone in Canada running a 20wt.
An often overlooked point. IMO, it points to my thinking that all of us are probably overthinking this thing some...
Originally Posted By: BGN
I would have no problem running a quality 20wt like Redline but I'm not just so I can say I told you so when it has 300,000 miles on it.
You're on! We'll see who gets there first, and who has the prettiest cam lobes when we do!

Originally Posted By: BGN
The GN as I've said runs stockish bearing clearances which just happen to be the same as many 2009 model cars. Oil temps rarely see 200 degrees. I run it hard for short bursts and it has a large oil cooler. It's an extreme example I know, but it shows that thick oils are sometimes needed even with relatively tight clearances.
A couple questions. First, a tad OT, but how do coolant temps run? Also, any concern about corrosion? All three of our cars (Avalon may be borderline) are driven so much that they get fully warmed every day. Does the GN get driven that much?

 

[BuickGN]

Originally Posted By: ekpolk
Originally Posted By: BuickGN
. . .

You called my TL a V6 Accord! How dare you lol.
As warped as it sounds, I actually wasn't thinking of the TL! Really. Maybe it was some form of sub-conscious mental slip...

Actually, I was trying to think of the least stressful, most modern app. I figured a Honda V-6 would be close to fitting that bill. But yeah, now that you mention it, that's genetically pretty close to the TL...

Originally Posted By: BGN
A couple points. The TL is opeated in a hot climate and winters rarely see freezing. I'm not running anything thicker than someone in Canada running a 20wt.
An often overlooked point. IMO, it points to my thinking that all of us are probably overthinking this thing some...
Originally Posted By: BGN
I would have no problem running a quality 20wt like Redline but I'm not just so I can say I told you so when it has 300,000 miles on it.
You're on! We'll see who gets their first, and who has the prettiest cam lobes when we do!

Originally Posted By: BGN
The GN as I've said runs stockish bearing clearances which just happen to be the same as many 2009 model cars. Oil temps rarely see 200 degrees. I run it hard for short bursts and it has a large oil cooler. It's an extreme example I know, but it shows that thick oils are sometimes needed even with relatively tight clearances.
A couple questions. First, a tad OT, but how do coolant temps run? Also, any concern about corrosion? All three of our cars (Avalon may be borderline) are driven so much that they get fully warmed every day. Does the GN get driven that much?


By the time I'm done, my cam lobes are going to be so pretty I'm going to mount them on the wall to stare at every day.

GN sees 160-170 degree coolant temps. Going to raise that to 180ish with the aluminum heads that are on it. Corrosion isn't much of an issue, OCIs are once a year or about 1,000 miles. I'm curious to see what effects the hotter coolant temp has on cylinder wear. Running ultra low coolant temps are more a thing of the past. Detonation is easy to fight off now and with the meth injection, combustion temps aren't bad. I see no need for the 160 anymore. In the past when it was a daily driver I saw weird things happening to the cylinders that I wasn't educated enough to figure out. It wasn't actual mechanical wear but almost looked like someone had sprayed acid on them. Maybe that was corrosion???