Are we kidding ourselves judging motor oils by UOAs?

[jthorner]

quote:

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U.S. Armed Forces use UOA exclusively for determineing OCI

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I don't have any problem with using a UOA(especially the TBN, viscosity, contaminants and oxidation information) to determine OCIs.

I am also a big fan of using UOA to catch problems early. In fact, catching the leaking intake manifold gasket early on our Oldsmobile is worth a lifetime of UOA expenses to me.

What I am calling into question is trying to split hairs about which oil is better than another based on UOAs with an emphasis on metals.

Alas we mortals have little else to go on

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John

 

[JohnBrowning]

JTHorner, I agree that in some cases it is a mute point. Recently a gentlemen had an AUdio that he had ran Amsoil and M1 in. While the difference in wear was 69% difference in his case the wear numbers were so low that it did not matter! If I remember correctly his wear numbers were single digit's after 8000 mile OCI. So yes useing UOA to decide wich one to use was not really needed. On the other hand we have seen some LS6 engines that showed huge preferences for cetain oils. In some cases the were numbers were cut in half from one oil to the next.We are talking triple digit and high double digit. In a case like this I think it is well within the accuracy limits of the testing and worth while to use as a tool!

We have seen a lot of Corvette's and Camro's that benifitted from the M1 15W50/5W30 mix and from GC. If not for testing no one would know if this was a good idea or a bad idea!

 

[haley10]

I don't use uoa's to evaluate an oil's ability to reduce wear myself. Mobil 1 often shows high iron and Terry likes Redline despite it's inability to be put into the numbers box by us laymen.

I just do an occasional uoa to check engine health.

300K or so is all I need out of an engine anyway.

Higher lead will steer me away from one in favor of another, such as in the LS1 engine. I think these wear metals are too small to be filtered or retained anywhere, so maybe it is an indication.

 

[bulwnkl]

In the overall? Yes. In some specific sets of circumstances for certain specific people? No.
$0.02

 

[Ugly3]

buster - Let me ask you this though. Take Patman's Vette. Say Mobil 1 0w-30 shows 22 ppm of Fe and 10 ppm of Pb. Then he switches to GC and now shows 11 ppm of Fe and 5 ppm of Pb. Say this happens repeatedly. Isn't it accurate enough to say that GC provided 50% less wear across the board?

No. Until PPM is correlated to actual wear you know nothing about wear from a UOA. Assume if you must but it is an assumption.

 

[JohnBrowning]

bugshu, You have not even tried the new M1 EP and you are going to rate it? How are you baseing your rateing with out haveing tried it? Their are no UOA of it either! The "Magic 8 Ball" oil rateing guide is not the way to go!

I also belive you are looking for the word "Tribologist" hope I spelled that correctly!

The U.S. Armed Forces use UOA to save us tax payers a small fortune in unneeded oil changes! It also helps to spot trouble in advance of an oil change! Our supply chain is currently the best it has ever been. They have plenty of oil on hand at motorpools!

 

[haley10]

quote:

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Originally posted by Ugly3:
buster - Let me ask you this though. Take Patman's Vette. Say Mobil 1 0w-30 shows 22 ppm of Fe and 10 ppm of Pb. Then he switches to GC and now shows 11 ppm of Fe and 5 ppm of Pb. Say this happens repeatedly. Isn't it accurate enough to say that GC provided 50% less wear across the board?

No. Until PPM is correlated to actual wear you know nothing about wear from a UOA. Assume if you must but it is an assumption.

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I wish we could get some insight from Terry on this, but it ain't gonna happen and I understand. I know he likes Redline and some of their uoa's tend to suck from the raw numbers we see. Experts have never steered me away from M1 because of high iron either.

I just use uoa's to check engine health periodically, etc.

I see my old car I sold on the road every day pushing 300k, so I think wear is not a big problem, just an oil holding up and maintaining tbn without sludging is important.

The wear aspect is probably a lot more relevant to diesel trucks that see a million miles than it is to us auto owners.

 

[MolaKule]

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It seems to me that using Used Oil Analysis in an attempt to judge distinctions between motor oils has a lot of problems with it which makes much of the speculation and conclusion drawing here on BITOG highly suspect.

1) Any wear particles which are trapped by the oil filter (which is after all an oil filter's job) are not left in the drain oil and are therefor not detected in a simple oil analysis.

2) Any wear particles which are left behind as deposits in the engine likewise do not show up in the oil. Thus lower solvency oils might have an advantage in UOA which is not representative of reduced wear.

3) None of the standard engine oil testing methods uses oil analysis as a wear measurement method. All of them use reference engines or other reference bench set ups, run the system through a sequence of operations, then make physical measurements on key parts to determine how much wear happened. I have never seen any data published anywhere which correlates these methods to analysis of used oil. Without demonstrated correlation, we are just assuming that low metal numbers in used oil mean low wear happened.

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1. Sheared metallic particles or particles due to corrosion are put into "solution" and that's what the UOA's are reading.

2. The definition of deposits are generally meant to be spent hydrocarbons as a result of oxidation of those hydrocarbons, and may be soluble or insolubles if the hydrocarbon is hard soot particles.

3. Standard engine wear methods use radioactive Fe tracing, wear metal particle count/weighing, and UOA's to determine oil and engine condition.

You will never see a published UOA from engine/oil manufacturers.

 

[Doug Hillary]

Hi,
Molakule - you said this;

"You will never see a published UOA from engine/oil manufacturers."

Care to elaborate please?

Regards
Doug

 

[buster]

It wouldn't surprise me then, based on what has been said above regarding wear, and from what I've heard from RL, that what we see isn't always wear. Especially with oils such as RL with high solvency. Hard to say. It's really the million dollar question at this point for me.

Would change my thinking and oil selection if I knew the answer.

 

[DJ]

quote:

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Originally posted by buster:
It wouldn't surprise me then, based on what has been said above regarding wear, and from what I've heard from RL, that what we see isn't always wear. Especially with oils such as RL with high solvency. .

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This is why I would not bother with a UOA on the first fill of an oil. Like I said before after you establish an oil in an engine I think the only thing left to drain out is going to be what was worn off during that oil use.

 

[JohnBrowning]

buster, This is why Terry always told use to give Redline at least 3 oil changes before sampleing. To often the added solvency was cleaning house. Now if an oil is allowing your engine to rust away that is just as bad to me as wear metal from contact. Wear metal is wear metal and errosion and corrision are equaly bad in my book.

 

[Stinky Peterson]

I too question the value of using oil analysis to judge oil quality, and I certainly would not try to make any conclusions from just a few samples. There are just too many variables that affect the results. The oil analysis test are designed to measure wear, contamination, and oil condition.

One thing I've learned from looking at gasoline engine samples is there tends to be a lot of variability in the results for no apparent reason. This makes the results hard to interpret and it is even harder to draw conclusions.

When we work with customers to optimize oil change intervals I like to see a dozen or more samples from each engine taken at different intervals. When comparing one oil to another we want to look at hundred's or even thousands of samples.

I also question the value of trying to judge oils by comparing VOA's. It is easy to say this oil has more of one additive than another but it isn't that simple as many of the additives work together in ways that even the experts don't fully understand. I do however have to admit that it is fun to compare oils and it is fun to experiment.

 

[buster]

John, if thats the case, one can then arque that Mobil 1's higher Fe #'s at times are do to greater solvency. But if your wear numbers come back 50% lower using oil A to oil B, I still think I'd chose oil A, even if the science isn't that good.

 

[427Z06]

I just wanted to say that I'm glad were discussing this topic in earnest again, even if it was discussed before. 1sttruck has been the latest to lead the charge and has contributed immensely, in my book. jthorner, thanks for bringing this topic to the forefront again...as it sure beats heated discussions on viscosities.

 

[haley10]

quote:

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Originally posted by buster:
John, if thats the case, one can then arque that Mobil 1's higher Fe #'s at times are do to greater solvency.

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Could also be argued that M1 lacks solvency.

Do we see reduced iron when LC is used??

 

[jthorner]

quote:

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John, if thats the case, one can then arque that Mobil 1's higher Fe #'s at times are do to greater solvency.

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Might be, might not be. We really do not have any way to know.

There are lots of questions of why Redline does not generally show great UOAs while the mystery oil German Castrol often does.

What I am saying is that we really do not have any way to *know* if GC is indeed superior to Redline at reducing engine wear while a casual reading of Used Oil Analysis results might lead one to such a conclusion.

Unfortunately none of us here can afford to do the kind of real testing one would need to do to correlate actual wear against UOA readings. The question remains, are we just kidding ourselves?

John

 

[Gary Allan]

(poster on Fox Mulder's office wall)

I WANT TO BELIEVE!!!

 

[rugerman1]

UFO's,UOA's: see any similarity?

 

[TooSlick]

Oil analysis does an excellent job of quantifying engine wear - IF you understand the data you're seeing ....

For example, the level of silicon/"dirt" correlates very closely with piston,ring and cylinder wear. Allow Si to get high enough and you'll see nickel from the intake valve stems, which are stainless steel. In a similar fashion, soot concentrations in diesel engines correlate nicely with valvetrain and ring, piston,cylinder wear. Finally, if you over extend an oil,let the TBN get too low and the insolubles too high, you'll see greatly increased bearing wear. You'll also see more bearing wear if you use an oil too thin for the application.

If you see significantly higher concentration of key wear metals like Fe,Cr,Al,Cu,Pb, there is certainly more wear taking place. It can be adhesive wear,abrasive wear,corrosive wear or some combination of these, but metal IS being removed from the internal parts and being put in solution/suspension in the oil.

The one question I can't answer is if you get a wear rate of xx ppm/1000 miles of say Fe, what does that mean in terms of ultimate engine life, or at least in terms of degrading performance over a long period of time? However, all things being equal, less wear and fewer deposits are certainly highly desirable from any lubricant....

Particles sizes typically form a "normal distribution" or bell curve and oil analysis captures those below about 5-6 microns. This concentration is representative of the overall amount of wear - that's the whole idea....

TS