dnewton3
Staff member
What is that "valid technical reason"?
Wear Increases After OC?
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Because there are too many uncontrolled variables. The ASTM test for measuring wear due to the oil is complicated and rightly so. It isolates the one single variable of the oil.
Measuring something is often the easy part. Ascribing the observation to one isolated singular variable is the difficult part.
dnewton3
Staff member
I think I understand our diversion of thoughts. This is a matter of how one views analysis and math models.
I look at things from a view of statistical analysis, and all the detailed math modeling.
The term "uncontrolled variables" as you use it would imply that because things are "uncontrolled", there is no validity to test results.
That's a laymans interpretation and very common. But it's also not true. In EVERY set of test data, there is variation. Some of that variation is controlled, some is not. The desire is to control as much as possible, but there is not a requirement to do so. The concept of "control" is often misinterpreted.
You do not need to "control" all inputs. You split them into two groups; controlled and uncontrolled.
- With the controlled group, you have the ability to manipulate the input(s), and if they correlate to some output, you can then work to assign causation, if possible.
- With the uncontrolled group, there may be correlation or not, and be causation or not, but you have no ability to manipulate the input.
Having an "uncontrolled variable" does not, in any manner, invalidate a test. It only needs to be accounted for in the data processing, and acknowledged in the analysis. Having an uncontrolled variable only limits you to further refining any result; it does not in any manner invalidate a result.
What we need to recognize is that there are many ways to measure "wear". Some methods are very precise, but require time and money consuming efforts and not at all usefull to the average person. Other methods are more general and very easy to apply.
The issue with very specific ASTM testing is that it focuses on only one aspect; that is both a good and bad thing. It can prove/disprove something in a unique way, but that method may also overlook other factors; it's sort of the "can't see the forest for the trees" concept. UOAs are just the oppostive; they see a large amount of information all at once, but they cannot focus on any one thing.
Using electron bombardment (just one example) is a very accurate way to measure wear on a cam journal, but to do so, you have to control the test in a lab, and it means tearing down an engine. You can find very specific info regarding some element of the lube as a manipulated input, but it ignores all other aspects of wear elsewhere. You can also only rely on that one example, as any effort to reassemble the engine again introduces a slew of other variables and would multiple the factors on orders of magnitude. Teardown analysis is great, but it's a one-and-done method.
UOAs cannot distinguish Fe of a piston ring from the Fe of a bearing journal, etc. But when the UOAs shows "low" wear numbers and low wear rates in succesive reports, there is good cause to believe that all is well. The technology of ICP itself is certainly proven and sound; that's not in question. UOAs also cannot see wear particles above 5um. As discussed before, using a UOA is a means of seeing some wear directly, and inferring other wear indirectly. UOAs also require no disassembly, obviously. They don't disturb the continued relationship of all parts relative to one another.
I believe it s grossly inaccurate to claim that UOAs don't track wear. They most certainly do. It's just a matter of how one wants to track that wear, and then acknowledge the benefits and limitations of that info; how it's collected, analyzed and reported.
Once the UOA data is derrived, it's then a matter of proper processing the data to reveal the rates and trends using statistical analysis. If one understand how to do this, and what the results can and cannot reveal, then you have a good, cheap way of knowing what's going on. Further, UOAs have been shown many times to be able to reveal some problem as it's developing; we've seen many examples in Blackstone news letters. It is wrong to say that every UOA will accurately predict all problems, because they are not that reliable in terms of a 100% guarantee. But they are FAR, FAR better than not doing anything. It's far better to have a false positve and seek a second opinion, then to never get a test in the first place and be blind-sided by an unforseen event. UOAs are very accurate, but not 100% accureate.
UOAs are not a means of singular determination for comparing/contrasting two lubes; that's a fools errand. But they are a good way to determine overall equipment health. They cannot ascribe a specific failure if something is wrong; they can only sound a general alarm. But that does not, in any way, make them useless. Any UOA which shows an undesirable value in wear or trend, is a notification to go look deeper into something. It's wrong to say UOAs cannot measure wear; they most certainly can. It's just that they cannot tell you what's wrong; you have to go figure that our for yourself. They can also imply when things are ok; they can show you if your data is "normal" (good averages with typical variance).
If we can agree on these priciples, then there's room to move forward.
I also look at things from the perspective of statistics and proper analysis. I learned that when I worked in the research department of a large corporation, we had two PhD mathematicians on staff who evaluated everything that left our lab. Mathematicians are very talented individuals and know a lot about a lot of things. One of the things I learned from them is that the statistical validity of data is not determined by the volume of data, the difficulty in obtaining the data, nor the effort employed to generate the data.
No one ever designs a test that doesn’t control variables. Yes sometimes you cannot control something but that is to be avoided like the plague. If it cannot be avoided then you need a separate analysis and test to determine how that uncontrolled variable influences the results. It’s literally a second investigation that is of similar scope to the one you wish to perform. It’s why standardized laboratory tests are always preferred to making up your own, those tests have been vetted to produce statistically significant results.
I’ll definitely agree that a UOA can track wear but it’s an observation not a determination. Again for the purposes of what I stated earlier in this thread you cannot use “real-world” spectrographic data to determine the comparative quality of motor oils. No one does that. You and I agree on this when you say “UOAs are not a means of singular determination for comparing/contrasting two lubes; that's a fools errand”. The rest of what you say in that paragraph is not debatable and I agree. The problem for me is that you’re looking at wear from an aggregation of causes not the single variable of oil.
No one ever designs a test that doesn’t control variables. Yes sometimes you cannot control something but that is to be avoided like the plague. If it cannot be avoided then you need a separate analysis and test to determine how that uncontrolled variable influences the results. It’s literally a second investigation that is of similar scope to the one you wish to perform. It’s why standardized laboratory tests are always preferred to making up your own, those tests have been vetted to produce statistically significant results.
I’ll definitely agree that a UOA can track wear but it’s an observation not a determination. Again for the purposes of what I stated earlier in this thread you cannot use “real-world” spectrographic data to determine the comparative quality of motor oils. No one does that. You and I agree on this when you say “UOAs are not a means of singular determination for comparing/contrasting two lubes; that's a fools errand”. The rest of what you say in that paragraph is not debatable and I agree. The problem for me is that you’re looking at wear from an aggregation of causes not the single variable of oil.
What ASTM test number are you referring to?
There is more than one that is part of the Sequence IIIG or IIIH, ASTM D7320 or D6891. Probably similar ones for compression engines plus others that aren't part of the Sequence.
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Yup, about 7 years ago some forum warrior on a BMW site ( hey, BMW was the only company offering a diesel AWD wagon in the states, sue me lol) lit into me for my OCIs and lectured me on how bad new oil is for the engine. That 25 watt genius also took the step to claim a dirty oil filter is better too. Just last month got it again on a different site. Hilariously in both cases neither could/would provide even an attempt at proof other than "everyone knows that" and neither jumped on the offer to buy my used oil to extend the life of their engines........crazy right? lol
Good stuff and always nice to see firm science deployed, when supporting facts are presented discussions and advancement occur instead of forum flames. However as always it's then the interpretation of the science where it gets murky.
From post #16
The paper did say that "new compounds" in the old oil may provide wear protection. I would draw the same conclusion myself since they cleaned the cam lobes in part of the test with mineral spirits to remove the antiwear film and when they introduced used oil back into the test the wear rate was high initially (like the fresh oil) but dropped to a much lower wear value compared to the new oil.
Does anyone here disassemble their engine and clean the surfaces with mineral spirits during every oil change? I mean I get the methodology and reason, it's very accurate science however I think it misses the mark in final interpretation. If I am using engine oil A and then change the oil with the same brand, spec, and viscosity that first round of oil laid down the protective film of agents it uses, if the additive package is not depleted then it should be active. It seems like it is being stated that the new oil STRIPS that protective film off to reapply a new one, but that makes no sense. Sure the cleaning agents attack deposits, but deposits would ride on TOP of the protective film in most cases. Regardless even if it did attack the protective film (not sure why an oil with additive A would be designed to STRIP additive A but hey) it would simultaneously be laying down it's protective film so there would never be zero film layer.
That test REMOVED the protective film layer before testing with used oil, that is not representative of the real world so while it is interesting test for the base properties, the real world application is impossible. In addition that paper is 20 years old, not sure even if the results were nail on the head conclusive that they would still be relative or applicable to today's oils.
And if the theory holds water than it gives credence to the treatments like EnergyRelease, MoS2, etc that apply an effect that lasts over many oil changes (and so unaffected by drains). Assuming they do what they say of course. Man what was the name of that stuff back in the 90s they claimed you could run your car 50k miles with no oil at all after using it once, was all over TV? LOL
What would be interesting and useful science if the theory is that the time needed for the new additives to be activated by heat and pressure is where the wear occurs is to find out how much heat/pressure/time is needed and then complete an alternative break in period to speed that up. Basically like heat cycles in tires.
In the meantime, I think I will go register the domain at buymyusedoil.com to get ahead of the rush.
What I gleaned from that thread and all the inputs from member Laminar Lou, who bought and read the SAE paper, was that they did all kinds of different tests, and one of them was to test used oil on a cleaned surfaced that was to be lubricated and measured for wear. It's not the first time I've seen were used motor oil actually has reduced friction and wear than new motor oil. Here's a graph from another study showing that.Good stuff and always nice to see firm science deployed, when supporting facts are presented discussions and advancement occur instead of forum flames. However as always it's then the interpretation of the science where it gets murky.
From post #16
The paper did say that "new compounds" in the old oil may provide wear protection. I would draw the same conclusion myself since they cleaned the cam lobes in part of the test with mineral spirits to remove the antiwear film and when they introduced used oil back into the test the wear rate was high initially (like the fresh oil) but dropped to a much lower wear value compared to the new oil.
Does anyone here disassemble their engine and clean the surfaces with mineral spirits during every oil change? I mean I get the methodology and reason, it's very accurate science however I think it misses the mark in final interpretation. If I am using engine oil A and then change the oil with the same brand, spec, and viscosity that first round of oil laid down the protective film of agents it uses, if the additive package is not depleted then it should be active. It seems like it is being stated that the new oil STRIPS that protective film off to reapply a new one, but that makes no sense. Sure the cleaning agents attack deposits, but deposits would ride on TOP of the protective film in most cases. Regardless even if it did attack the protective film (not sure why an oil with additive A would be designed to STRIP additive A but hey) it would simultaneously be laying down it's protective film so there would never be zero film layer.
That test REMOVED the protective film layer before testing with used oil, that is not representative of the real world so while it is interesting test for the base properties, the real world application is impossible. In addition that paper is 20 years old, not sure even if the results were nail on the head conclusive that they would still be relative or applicable to today's oils.
And if the theory holds water than it gives credence to the treatments like EnergyRelease, MoS2, etc that apply an effect that lasts over many oil changes (and so unaffected by drains). Assuming they do what they say of course. Man what was the name of that stuff back in the 90s they claimed you could run your car 50k miles with no oil at all after using it once, was all over TV? LOL
What would be interesting and useful science if the theory is that the time needed for the new additives to be activated by heat and pressure is where the wear occurs is to find out how much heat/pressure/time is needed and then complete an alternative break in period to speed that up. Basically like heat cycles in tires.
In the meantime, I think I will go register the domain at buymyusedoil.com to get ahead of the rush.
There were other tests involved too (in that referenced link where member Laminar Lou discussed the paper), where the built-up tribofim wasn't disturbed and new oil was added, and the wear rate then went up until the tribofilm from the new oil was built back up. From his post #12: "They basically found that there was a scavenging effect on the anti wear film of the previous oil when a fresh oil is introduced."
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To add, what it sounds like is that the chemistry changes somehow as the oil becomes more used. Doing an oil change with the same exact oil is then introducing the chemistry of the new oil to the tribofilm of the old oil, and sounds like that causes the existing tribofilm to be stripped off to some degree.
Like I mentioned earlier in this thread (post #40), some Ford Coyote V8s will start making a ticking noise (Ford has a service bulletin SSM 49761 on it, and call it a "typewriter tick") right after an oil change is done, even if the same exact oil brand and viscosity is used. IMO, the ticking starts because the new oil changed the friction level between moving parts due to the new oil stripping the existing tribofilm to some degree. And some of those engines will stop ticking as miles are put on the oil, which sounds like the friction level went back down as the new tribofilm was built back up. Also, guys will add only 150 ml of Ceratec (friction modifier) to the oil (8 to 10 qts depending on Coyote model year) after the ticking starts, and the engine tick will almost instantly disappear due to the change in the friction level of the oil. There are lots of YouTube videos showing that.
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A "dirty" oil filter definitely has increased filtering efficiency as the flow decreases. It's been discussed on these pages countless times. It's common for some to leave the same filter on an engine for two or more oil change intervals. Perhaps the "25 watt genius" knows more than you think.
Those ASTM test standards are to test/qualify/certify/license an oil in a fired engine. The wear limit spec is pretty large if I recall. Those tests don't try to measure anything related to wear rates, just the total measured wear to determine it's below the specified wear limit after the test sequence was performed.
Nope ... it's been discussed many times why an oil filter actually gets less efficient as it loads up and the delta-p across it becomes higher. Oil filters and air filters do not act the same way as they load up. Air filters do get more efficient, but oil filters don't because the delta-p across oil filters is much higher. That phenomena was also seen in the ISO testing performed by Ascent. Read the thread link below from where it jumps in. See posts #391 thru #393 in that thread.
And the flow through an oil filter and the oiling system on an engine with a positive displacement oil pump doesn't decrease as long as the pump is not in pressure relief. An oil filter would basically have to be completely clogged for that to happen.
Would you all like to see ISO 4548-12 Oil Filter Lab Testing Comparison, Efficiency & Capacity, Pressure vs Flow, Bubble Point, and Burst?
I have this as a “watched” thread, so if you do happen to start a new one, could you put a note or link in this one to direct followers to the new thread? Thanks!! Yes, no problem I can do that.
bobistheoilguy.com
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Nevertheless, it does measure wear as opposed to a spectrographic analysis that does not measure wear. UOA may observe it but does not measure it. I don't think I've ever mentioned wear rates in my comments.
I do know there are other tests but I don't know whether they are proprietary. If you find one that uses spectrographic analysis (as in a $30 UOA) let me know.
dnewton3
Staff member
I would agree in general. For clarification, I would say that the "validity of data" is not in question, but the quality of analysis accuracy, relative to the sample size and total population. The accuracy of stdev is very much dependent upon the quantity of samples taken. Less than 30 samples makes for an exponentially larger error with each step of fewer samples taken. Conversely, taking more than 50 samples doesn't greatly improve accuracy and if costs are associated with that data collection, the ROI plummets horribly. 30-50 samples is what you need for a good balance between efforts and accuracy.
I do agree; you don't have a test with no controlled variables. But you certainly can and do have tests which acknowledge the uncontrolled variables. It's a rabbit hole you can go down, trying to control everything.
Yes - we agree here. I believe that UOAs cannot be used to determine the performance differences between two oils, unless a gigantic slew of samples were taken for all oils tested, and a host of other caveats would be in place as well. In a practical sense, UOAs are worthless to compare/contrast lubes in the manner which BITOGers want to apply them.
UOAs are, however, good for using as a means to track your overall equipment health and understand if the system is "normal" or "abnormal", and if any trends are developing (pro or con). This approach can be taken both in a sense of micro-analysis (one unit), or macro-analysis (multiple units). The concept of "controlled" and "uncontrolled" variables only matters in the definition of how you apply and interpret the conclusions.
Here's an example from which I can speak directly:
Consider you have a manufacturing process that makes heat exchangers. Those heat exchangers use copper "hairpin" tubes. Those hairpin tubes come off of machines that each make the hairpins from giant copper tube coils. You have six machines. Each hairpin goes into an assembly process that indiscriminately uses the hairpins; hence, a hairpin from any one of the six machines gets matched with other parts from the other 5 machines, in an uncontrolled measure. If the hairpin leg length is a critical characteristic, then you measure the legs of sample sets from each machine.
* in micro-analysis, you need to determine what each machine is capable of doing, and perhaps make adjustments to that machine to meet spec and stay in range. The machine will have a resultant average and stdev for it's unique process
* in macro-analysis, you take the data from all 6 machines and then do the same again, but as a group data and not individual machines, because that is how the product is presented to the downstream customer processes.
This is very important ... You have to understand not just what each unique hairpin machine is capable of (micro-data), but what the group is capable of (macro-data).
When I speak of macro-data regarding engines and lubes, it's very good data to have; that of what the marketplace shows. If your personal 3.8L GM v-6 is having wear metal rates near the averages and well within the stdev, then all is "good" with your engine. You don't need 30 samples of your engine to determine if it's "normal". But if you want to start validating one specific oil you choose in your own personal application, then you do need a minimum of 30 samples just to establish a baseline. The "uncontrolled" inputs (ambient temps, driving distances, etc) all meld into the micro-data collection point, when you look at the data on a "per mile" rate basis. And the longer you stretch out an OCI, the more the minor blips of inconsistency fade.
I'm not trying to say that UOA data is the only thing you need to understand lubes. I'm saying that UOA data most certianly is useful in tracking engine wear, relative to "normal" macro data experiences. If you want to know how any one lube affects any one part, a UOA cannot tell you that; you'd have to do ASTM testing and manipulate only one or two variables in a tightly controlled test. But that's not what we need here at BITOG; we only really want to know if the lube is doing a good job. Sadly, there are lot of people here who think they can determine what is "best" (or better/worse) using a UOA, and that is patently untrue. Also, UOAs cannot distinguish the origin of wear; they can only hint at logical places to look. Cu isn't going to come from a piston ring or timing chain, for example. Cr isn't coming from a rocker arm. Etc, etc ...
UOAs are a great tool, if you know how to properly use the tool, and what the tool can and cannot tell you. In this, I think we're in primary agreement. Where we diverge is when you say that UOAs can't meausre wear; that statement I vehemently disagree with, because it's too much of a blanket statement and a bit misleading. UOAs measure direct wear (
ASTM testing is a great tool also, but it also has limitations moreso rooted in costs and time; things which most BITOGer seriously lack in terms of discovering if their favorite flavor of motor oil is "best", or "better" than some other flavor. Also, ASTM tests cannot tell you if the engine is behaving in a "normal" fashion or not; that's not their intended purpose.
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David, thanks for your detailed and thoughtful responses in this thread.
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Because they do not measure wear in the traditional sense of the word—not really. Oh sure, they can reinforce the fact that wear is happening, but we already know that because that happens every time the engine is run or it can tell us that “more” wear is happening, but that still does not equate to anything measurable.
For example, there is a UOA that shows 10PPM of Fe and for the next 4 UOAs, it is 15PPM and then jumps to 100PPM and then 300PPM. What is that telling me? From my perspective, it tells me that I may have a component in the engine that is beginning to fail and is generating more Fe. OK; so, we discover it was the timing chain and we replace it and within a few UOAs it returns to 15PPM. Where does that leave us?
What does 1PPM of Fe equate to in actual wear? Is it 0.000001 or an inch or 0.00001 of an inch? How many groups of 5PPM of chrome (for example) equate to worn rings that have to be replaced? How many PPM of chrome are in the engine from the beginning? Can we take that 5PPM and accurately predict the point in time or mileage where the performance of the engine degrades and parts need to be replaced?
I do think UOAs have their place (I have run nearly 100 in my time), but I cannot take that data and say in x miles I will need to replace anything in the engine unless there is a part that causes the readings to suddenly rise. Even then I only know that something is going to fail, but not when because a UOA will not tell me that "x" amount has worn on the timing chain and that amount is "x" amount out of tolerance. A UOA will tell me with certainty if the oil has reached its useful life, but will it tell me I have between 75,000 and 100,000 miles of life remaining in the engine?
I totally understand that a UOA is a cheap way to try and measure wear and that other methods are either cost prohibitive or simply do not make logical sense, but unless you can show me how a UOA can be used in the manner that I have stated above, I remain unconvinced.
Perhaps I am being far too literal here, but hopefully you can see my perspective.
True, it does make a direct measurement of the cam lobe. Depending on the API rating/license certification as time went on, the max wear limits have changed. Seems to have went down from around 120 um to 60 um (micrometer) from what I can find. Also the ASTM D6891 is ran for only 100 hours, and it's done on the fired engine at very low RPM (800 & 1500 RPM) where the wear rate would probably be pretty low compared to much higher RPM.
The ASTM D6891 does reference also making an "iron wear metal concentration" measurement ... so UOA. But doubt it's used as part of the criteria to pass or fail as the direct measurement is the primary factor. Wouldn't know how the UOA comes into play without seeing the entire ASTM spec, which I'm not going to pay to see, lol. In a test like this where the engine run time is pretty low time and low RPM in the scheme of things, obviously a direct wear measurement is the best way to do it.
I'm wondering if any controlled tests have been done that do a much more long term engine wear test (like 100K+) on their chassis dyno (like Mobil, BMW, etc do) and they take regimented UOAs along the way as monitoring data/info before the test ends and they do a final tear down, inspection and measurements. Seems like controlled UOAs would be beneficial information in a very long term test like that.
ASTM D6891-21e1
Standard Test Method for Evaluation of Automotive Engine Oils in the Sequence IVA Spark-Ignition Engine
www.techstreet.com
"The primary result is camshaft lobe wear (measured at seven locations around each of the twelve lobes). Secondary results include cam lobe nose wear and measurement of iron wear metal concentration in the used engine oil."
You seem to be moving the focus of the original subject matter of "does wear rate increases right after an oil change", to now trying to find some kind of relationship between determine wear rates from UOAs and how that can somehow equate to if an engine component is actually worn out or not. Nobody has made or claimed any kind of connection between the two. There is no connection between the two, because the only way anyone could determine if an engine component is worn out is to visually inspect and measure it, and compare that to the service manual specs. Yes, a change in trended UOA history may raise a red flag that something is going on, but it's not going to tell you that 0.0001" wear happened on the cam lobes. In industries utilizing many high value lubricated machines, they typically have a regimented UOA program to monitor for issues starting early so they can prevent a major break down catastrophe.
Trend increases in wear metals in UAOs can certainly raise a red flag and make someone dig deeper for a possible cause. Member @TiGeo did exactly that when his VW's UOAs started showing changes in the long tracked trends, and further digging found metal particles in the oil filter. Ended up there was a major problem going on. He can elaborate if he wishes, or point you to his thread.
Based on what dnewton3 has said, I think a regimented and controlled long term UOA plan can be useful, and can show if wear rates change. But they will never tell you to do a rebuild on your engine ... that's up someone tearing it down and making measurements to compare to the service limits in a service manual.
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Simply put, no, I am not. I am responding to DNewton's question.
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