"Engine oil viscosity has VIRTUALLY NO EFFECT ON WEAR."

[Ugly3]

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Originally posted by wulimaster:

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Originally posted by Ugly3:
]The problem I have is that I have not seen any data that suggests the wear metals in a used oil analysis relate in any way to actual engine wear. Look at the Paradise Garage study, there is virtually no wear reported in the 1000 mile used oil analysis from 5,000 miles to 15,000 miles. I don't think that can be so I think there must be some anomoly going on.

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If you just look at the numbers between 1k and 12k you will get a better idea of the wear.

I noticed that comparing the Amsoil 3.5HTHS to the Mobil 1 3.08HTHS wear numbers it shows that over the 11k period between 1k and 12k the Amsoil has about 1/2 to 1/3 the wear on the iron/lead/copper/aluminum.

I wonder if this difference is due to the HTHS difference?

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I guess I failed to make my point well enough. If the iron ppm were 17 on one used oil analysis and 71 ppm on another used oil analysis from the same engine how do we know the ppm numbers relate to actual ware in the engine? I have seen no data to corrolate ppm in a used oil analysis to actual engine wear.

 

[LarryL]

I have an '84 Honda Civic wagon that has 375k miles and the engine has never been apart or the head removed. In those years I've gone from 5w30 dyno to 5w30 synthetic to 10w30 to 10w-40 to 15w-50 and now 20w-50. These jumps have been paced by oil consumption between oil changes, which is about a half quart per 5k miles, a rate that has been pretty constant for 20 years. The compression is at factory new specs and with in a few pounds from highest to lowest (208, 205, 209, 205). My only reason for steping up the viscosity was to control oil consumption. I'm getting a bet nervous waiting for something to happen... there's no place to go, anymore, with the viscosity.

 

[Mystic]

I don't think you have to be an engineer to realize that for ordinary cars and trucks viscosity very easily COULD have an effect on engine wear. After all, you don't put 20W-50 oil in an engine in the wintertime in a location where it gets cold in the wintertime, or at least I don't do so. I don't like the idea of 10w30 in an engine in cold weather, especially in a vehicle where 5w30 or 5W-20 are the recommended viscosities anyway. 10w30 might be the oil going in your car or truck engine if you take the vehicle to a new car dealership for oil changes and they just use a cheap bulk engine oil. Maybe that would help to explain weather starting problems?

Now in a race car they may well use a thin oil for qualifying. And they might use a thicker oil for the actual race. With the new synthetic oils they may even use a thin oil for the actual race. But a racing car is not an ordinary street vehicle. You don't drive a Formula 1 race car to and from work every day.

 

[Mystic]

Of course, like LarryL says, as a vehicle ages it might need a thicker motor oil.

 

[Terry]

When I spoke ( for BITOG at Bobs request) at Speedtalk.com streaming radio program about vis and issues related in racing applications, all these issues were superficially addressed in plain english.

Bearing and engine construct/use are first considerations.
Secondly a suitable fluid formulation for the engine.

Then:

Test and verify the combination, using low cost oil analysis techniques in addition to recording of engine performance at the dyno or on the track. Manually or via datalink.

The broad statement that; " oil vis has virtually no effect on wear is poppycock". Not to mention misleading.

Which vis; dynamic, kinematic ?

Which fluids Newtonian,plastic,dilantant,pseudoplastic,
thixotropic ?

See the last 2 articles by Bob Grisham in STLE's magazine from Dec and Jan for more info. This is not secret info, you just have to think and work to learn it.

Doug,Ken2, and John are correct and on the right track.

Bottom line ,you can be the dimmest bulb on the Christmas tree and if you use oil analysis( interpreted properly) no more than annually, record the most crude MPG info , you can find the sweet spot for your street vehicle.

TD

 

[JohnBrowning]

I want to clarify that I am in no way disocunting UOA!!! I am only trying to make it clear that UOA is only relavant if you have enough data points to see a trend. Forensic tear down is right now and in your face! This is especialy true if you weight the parts prior to assemble adn after tear down! If you did this repeatedly and also did UOA each time you could quckly make a master key/Profile for any given engine in no time flat! THis would allow the use of UOA as a precision tool for that given engine series.

The way we use it here on bobistheoilguy you really need years of experince and it is almost an art. THis is why Terry can see thing we rank amatures can not!

 

[Terry]

John said; " If you did this repeatedly and also did UOA each time you could quckly make a master key/Profile for any given engine in no time flat! THis would allow the use of UOA as a precision tool for that given engine series. "

Thats exactly what has been done in the past for those that care enough to UOA the very best !

My point is that much of the arguing over theory and semantics is eliminated by relatively lower cost non-intrusive testing.

John, keep in mind that not every fluid needs to be so shear resistant that is a liquid plastic.

Well made Bearing design and controlled operating temps don't require the worlds most robust molecular structures or super stable vis profiles in every situation.

As a matter of fact poor performing lubes in bench testing can perform admirably in well maintained cars, another reason for periodic and judicious use of used oil analysis.

 

[lobo11]

Quote:
The HTHS is all that counts! Additive packages help but they are secondary AW agents. The additive package only helps when the base stock fails.

I don't know if this is correct--
From Chemistry & Technology of Lubricants (second edition)--"Ester groups are polar an will therfore affect the efficiency of antiwear additives. When a too polar base fluid is used, it, and not he antiwear additives, will cover the metal surfaces. This can result in higher wear characteristics. Consequently, although esters have superior lubricity properties compared to mineral oil, they are less efficient than anti-wear additives."

In the same way when PAO's are formulated esters and other basestocks with higher solvency are added to the PAO specificly so the anti-wear additives can function properly. A good motor oil is more than just a good basestock.

 

[buster]

I guess I stand corrected in that HT/HS is more important then I realized. However, I'm not convinced it's a black and white issue where the higher the better is always the case.

Mobil 1 R has a HT/HS of 3.0. And some of these 20wt oils have low HT/HS. Doesn't seem to have that much of an impact from what I've seen, partly bc the additives are probably better and the engines just don't require it.

 

[JeepZJ4.0]

Go look at the VOA of a 4.0L Jeep running 40wt, then compare it to a 30wt. Then try and feed me this quote again.

 

[TallPaul]

quote:

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Originally posted by lobo11:
I don't know if this is correct--
From Chemistry & Technology of Lubricants (second edition)--"Ester groups are polar an will therfore affect the efficiency of antiwear additives. ...

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I don't know if it is correct either, but look at Redline, gobs of ester and gobs of antiwear additives. Somehow they work together--I hope.

 

[G-MAN]

quote:

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Originally posted by Ugly3:
I guess I failed to make my point well enough. If the iron ppm were 17 on one used oil analysis and 71 ppm on another used oil analysis from the same engine how do we know the ppm numbers relate to actual ware in the engine? I have seen no data to corrolate ppm in a used oil analysis to actual engine wear.

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Where do you think the metals in a used oil analysis are coming from if not from wear?

 

[TallPaul]

Here's an interesting quote from "Lubrication, A Tribology Handbook," edited by M. J. Neale:

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The effective viscosity of a lubricant in a bearing may be different from the quoted viscosity measured by a standard test method, and the difference depends on the shear rate in the bearing.

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The accompanying chart shows a "typical" straight 30 having higher effective viscosity under high sheer than a "typical" 20w50. The chart also indicates this high sheer rate that may be happening in the bearing is much higher than the sheer rate at which the test was run.

So I am wondering if the "standard test method" is HTHS and then that parameter is not as reliable as we may have thought. And different engines and/or conditions of the bearing may have bearings that are harder or easier on oil.

 

[TallPaul]

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Originally posted by Motorbike:
TallPaul

Can you recall anything Jim Fitch has written concerning the topic ? If so , please post .

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Don't recall. Would have to search Noria. No time now, digging out of snow. 10-12 inch drifts. Will try later. Hey, Callisa said something interesting about HTHS, I believe on this site (for the short while he was posting here).

 

[TallPaul]

From this thread: LINK.

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Originally posted by Callisa:

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The higher the oil viscosity, the thicker the oil film and the higher the HTHS, the lower the wear.

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I've seen the bearings in a Diesel engine, having run with 0W-20 oil on a Dyno. Diesel engines are most of the time more critical then Gasoline engines, due to higher pressures.

The bearings and especially the camshaft were perfect.

It's the performance that counts. Not HTHS.
You gain a little fuel economy with lower HTHS, that's why there is an industry trend over the last years towards lower viscosities.

Having higher HTHS does not mean automatically lower wear. The oils improved a lot since the invention of HTHS in the beginning of the '90's.

Stay curious.

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[TallPaul]

From same thread:

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Originally posted by Callisa:

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You can really spec oil on the basis of HT/HS viscosity and almost forget about the SAE grades.

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When this report was written in 1990, Exxon statet at the same time in a paper in Germany: "It's impossible to formulate a 0w30 oil with a higher HTHS then 2,9. It is possible today.

The reason for that paper where damages on bearings due to temporary loss of viscosity in the bearings. This lead to the "invention" of HTHS.

Today, I would rather go with performance in engine tests, not HTHS.

The additve package does the (wear) performance of a modern oil, not the HTHS.

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[pscholte]

You know, the thought just occurred to me...for something as ubiquitous as motor oil, and having been around for, what, about 100 years, and which is the subject of much research and "technical/formulation science," and which has scientific/technical societies that examine it and test it (and should understand it)...there surely is still alot of speculation about this stuff...you'd think there would be a constant and consistent body of scientfic knowledge by now...considering all this, I believe I am content just to rely on the Elves and their Black Forest magic! That works for me just as well as the 10 to the 145th power number of opinions and speculations I see.

 

[buster]

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You know, the thought just occurred to me...for something as ubiquitous as motor oil, and having been around for, what, about 100 years, and which is the subject of much research and "technical/formulation science," and which has scientific/technical societies that examine it and test it (and should understand it)...there surely is still alot of speculation about this stuff...you'd think there would be a constant and consistent body of scientfic knowledge by now...

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Totally agree. In fact as much as I think I have learned on BITOG, I'm still left with a lot of questions. Especially in viscosity and base stock realm.

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I've seen the bearings in a Diesel engine, having run with 0W-20 oil on a Dyno. Diesel engines are most of the time more critical then Gasoline engines, due to higher pressures.

The bearings and especially the camshaft were perfect.

It's the performance that counts. Not HTHS.
You gain a little fuel economy with lower HTHS, that's why there is an industry trend over the last years towards lower viscosities.

Having higher HTHS does not mean automatically lower wear. The oils improved a lot since the invention of HTHS in the beginning of the '90's.

The additve package does the (wear) performance of a modern oil, not the HTHS.

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I'd have to agree with this guy. Additives are constantly being devloped and look at what we've seen on here in terms of analysis. I havn't noticed any significant differences based off of HT/HS.

[ January 22, 2005, 03:30 PM: Message edited by: buster ]

 

[moribundman]

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I havn't noticed any significant differences based off of HT/HS.

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The lack of observation is not proof of anything.

 

[buster]

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The lack of observation is not proof of anything

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Never said it was. Read again.

The most over rated, over hyped spec talked about on this board has been ACEA A3. Most if not all X-40wt oils carry the A3 approval. Most if not all 40wt oils, do not provide better protection then 30wt A1 oils. You don't have to have an A3 rated oil in all engines. Is Mobil 1 R A3 rated or 0w-20? Nope. Mobil 1 0w-40 is A3 rated. Doesn't seem to offer any benefit over Mobil 1 5w30 A1 rated in most modern engines. If your car calls for an A3 rated oil, then use one.

And where are all these Corvettes and Vipers with Engine failures running on Mobil 1 A1 5w/10w-30? A 10 cSt oil as well.

[ January 22, 2005, 03:57 PM: Message edited by: buster ]