UOA + Ferrographic Analysis

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http://forums.tdiclub.com/showthread.php?s=e50ba245b8cd46e8641d55028a5f0324&t=18757 This is old, but interesting.
 Quote:
But since the regular analysis will not indicate the severity of the actual wear this is where ferrography comes into play. Look at both of the spectroanlysis oil samples taken. Based on those you would not suspect that the 0w30 engine would have any problems because the wear metals are so low. The fact is the type fo wear that is occuring is severe. The oil is working but it is not preventing dangerous types of wear from occuring.
Theoretically, you could have one UOA with Fe @ 50ppm, another with 25ppm, but the oil that came back with higher Fe is actually protecting the engine better.
 
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Buster, The more I learn about UOAs the more I think the only real purpose for them, for the average person, is to detect water or high fuel. I do 10,000 mile OCIs so not much need for UOAs.
 

buster

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Given the inherent limitations spectrographic oil analysis presents (5 micron max size limitation), there are many cases where catastrophic failure/large particle generation may be taking place (as camshafts are prone to do)with no indication whatsoever given with spectrographic analysis. I have just been through a series of just such camshaft failures on a fleet of trucks. The camshafts were defective but the manufacturer had no knowledge which were and were not defective. Spectrographic oil analysis results for the fleet were all well within limitations for the engines, with no specific indications of which were potential failure engines. Ferrography revealed in one oil analysis result which engines were and were not failure candidates. The regular use of spectrographic is indeed invaluable, however, limited
 
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 Originally Posted By: tig1
Buster, The more I learn about UOAs the more I think the only real purpose for them, for the average person, is to detect water or high fuel. I do 10,000 mile OCIs so not much need for UOAs.
UOA's are useful as follows: 1) TBN - Determining if there is any active additive in the oil left to do it's job as cleaning/protecting the engine and whether is is suitable for continued use assuming all else is ok with the oil. Also good for determining how stressed the oil is in your application with your OCI. 2) TAN - Is the oil too acidic to adequately protect the engine from wear. Also good for determining how stressed the oil is in your application with your OCI. 3) Insolubles - Do you have an air filtration problem or poor quality fuel problem or some sort of external dirt making it's way into the oil via a bad intake gasket etc. 4) Normal wear metal trending to see where your engine sits when mechanically sound. Should you see a spike in numbers with no change in your oil choice, driving patterns or any other factor may be an indicator of a problem developing 5) Fuel dilution problem due to an ailing spark system component, fuel delivery components like injectors etc. 6) Coolant - Head Gasket/Head/Block failure related. Other than that, they are useless IMO!
 
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 Originally Posted By: StevieC
 Originally Posted By: tig1
Buster, The more I learn about UOAs the more I think the only real purpose for them, for the average person, is to detect water or high fuel. I do 10,000 mile OCIs so not much need for UOAs.
UOA's are useful as follows: 1) TBN - Determining if there is any active additive in the oil left to do it's job as cleaning/protecting the engine and whether is is suitable for continued use assuming all else is ok with the oil. Also good for determining how stressed the oil is in your application with your OCI. 2) TAN - Is the oil too acidic to adequately protect the engine from wear. Also good for determining how stressed the oil is in your application with your OCI. 3) Insolubles - Do you have an air filtration problem or poor quality fuel problem or some sort of external dirt making it's way into the oil via a bad intake gasket etc. 4) Normal wear metal trending to see where your engine sits when mechanically sound. Should you see a spike in numbers with no change in your oil choice, driving patterns or any other factor may be an indicator of a problem developing 5) Fuel dilution problem due to an ailing spark system component, fuel delivery components like injectors etc. 6) Coolant - Head Gasket/Head/Block failure related. Other than that, they are useless IMO!
FOR ME: 1) I use M1 oil, no TBN worries 2)Again I use M1 oil, no TAN worries 3)Insoulbes, I use M1 filter, no filter worries 4)I use M1 oil, no metal wear worries 5)My engines stays well maintained at all times and well oiled with M1, no worries 6)Coolant is monitored weekly, any potential coolant loss is detected immediatly. Besides if coolant made it's way into the engine M1 oil can handle it, no worries. Don't Worry, Be Happy! HUMOR!
 
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Hey bud, While M1 is a darn good product and protects extremely well, there may be external factors at work taking away from it's "hard-work" so to speak. Occasional UOA's are a great way to check on your oils health and see how it is faring in your engine as a double check to make sure your engines possible mechanical problems aren't shortening the oils life. My uncle just blew his engine in his Dodge Spirit because he over used the oil in it a few times and developed a ring problem which became catastrophic and severely damaged the engine. A UOA could have shown him this coming and saved him the $800 on a used engine that we are putting in.
 
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 Originally Posted By: buster
Theoretically, you could have one UOA with Fe @ 50ppm, another with 25ppm, but the oil that came back with higher Fe is actually protecting the engine better.
Yes, but that is the exception, not the rule.
 
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 Originally Posted By: buster
 Quote:
Given the inherent limitations spectrographic oil analysis presents (5 micron max size limitation), there are many cases where catastrophic failure/large particle generation may be taking place (as camshafts are prone to do)with no indication whatsoever given with spectrographic analysis. I have just been through a series of just such camshaft failures on a fleet of trucks. The camshafts were defective but the manufacturer had no knowledge which were and were not defective. Spectrographic oil analysis results for the fleet were all well within limitations for the engines, with no specific indications of which were potential failure engines. Ferrography revealed in one oil analysis result which engines were and were not failure candidates. The regular use of spectrographic is indeed invaluable, however, limited
This is one reason to use Rotrode analysis, which has a 10-20 micron upper particle detection range. Combined with ICP spectroscopy, it provides a highly accurate window into the distribution of wear particles.
 
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I think Pablo said it best by saying we need to be "cautious" when using UOAs as a measure of wear. The UOA without particle analysis may catch wear or it can miss it entirely. IMO, it is probably not wise to say UOAs "always" are a measure of wear and it is not wise to say UOAs are "never" a measure of wear. It is probably better to say it "can be" useful to indicate wear and the more information we have, such as expert analysis, good trending, etc. the more useful it can be in this regard. I think in general we all like to see lower wear/contaminant metals than higher. I recently posted an example of a cam follower that failed in a 2.0 SI engine and there was no trace of evidence in the UOA trends for that car. Here is a counter example of the same engine with exactly the same problem where a UOA clearly showed something wrong (on a side note, this UOA is one of the "outliers" that RL_RS4 correctly identified as an engine with a problem after I posted the revised ppm FE/1000 miles graph for the UOAs we have on this engine a few months ago, but I only learned of the engine problem last week):
 Originally Posted By: corradokidg60
...Here's my Blackstone oil analysis for 40k miles worth of changes (4) - the last oil change shows metals in it because I later found out I had the dreaded HPFP/intake cam/cam follower wear issue. \:\(
So again, I think being "cautious" is the key.
 
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buster

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I'm not trying to discredit UOA's because M1 shows higher Fe levels in some engines. I'm just pointing out that there are limitations to UOA's. "Cautious" is the right word.
 
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 Originally Posted By: buster
I'm not trying to discredit UOA's because M1 shows higher Fe levels in some engines. I'm just pointing out that there are limitations to UOA's. "Cautious" is the right word.
Agreed! \:\!
 

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 Originally Posted By: buster
I'm not trying to discredit UOA's because M1 shows higher Fe levels in some engines. I'm just pointing out that there are limitations to UOA's. "Cautious" is the right word.
Watch out buster, people are likely to view this posting about UOA's as a Red Herring.... M1 is the REAL problem! LOL!
 
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EDIT NOTE: If this post doesn't seem to flow, it's because I wrote it about three hours ago, but couldn't finish and post before I had to go to several meetings. AFTER hitting the "post" button, I realized that many others had posted since...
 Originally Posted By: tig1
Buster, The more I learn about UOAs the more I think the only real purpose for them, for the average person, is to detect water or high fuel. I do 10,000 mile OCIs so not much need for UOAs.
With complete understanding that they're not by any means a comprehensive indicator of everything that's going on, you can get more than that from an inexpensive UOA. If you notice an abrupt change in any of the measurements, that will be a valuable clue from which you can investigate further. Potentially damaging intake leaks, and/or poor air filtration show up easily via the silicon readings, occasionally confirmed by an uptick in what would appear to be abrasive wear. Excessive insolubles are also an indicator that you may be headed toward a sludge problem. On the other hand, it is obvious and indisputable that literally millions and millions of drivers all around the world buy vehicles and drive them for years and years, never doing a UOA, and never having any discernible problem with their engines. I'd even bet that the majority don't have any idea that UOA is readily available to them, or even perhaps that OA exists at all. To me, this is all about perspective and choice. I like doing UOA, and choose to do them because I like knowing as much about my car as I can. But I'm not naive about UOA either. With the low end, inexpensive tests, you get limited, yet valuable, information. I'm also tired of hearing the, "just change it -- it's cheaper" argument, which incorrectly presumes that the only reason for UOA is determining the length of one's OCI. Ironically, that's a very minor part of why I do UOA (for now, my warranty dictates my OCIs). Hey, no one is forcing anyone to do UOA. Those who don't wish to can keep their blinders on, and drive blindly with the millions of others. It's not as if that's an unsafe bet...
 
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Ferrographic analysis is a nice add on/diagnostic when there is reason to believe that impending failure or internal damage is evident.. One must use caution, however, because you are relying on human interpretation of a visual field in most cases. The repeatability of ferrographic analysis on repeat samples and/or from technician to technician is not as robust as ICP analysis of a well homogenized sample. RS's comments are well taken.
 
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PQ would add confidence to most UOA. It tend to go with RS's leanings too as qualified. For your standard stroke (most of us), you're testing the oil's endurance over your usage variable. The wear is what the wear is if you're conforming to OEM specifications under OEM guidelines for your severity of service or lack there of. ..but let's say one of the steadfast objectors to using UOA as a wear indication tool decided to go up in visc for one UOA and saw a significant drop in levels?? Would they scoff at it and say "Nope, I have no faith in this UOA ..I'm going back to the other stuff because only a fool would react to such weak evidence". I don't think so
 
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 Originally Posted By: buster
I'm not trying to discredit UOA's because M1 shows higher Fe levels in some engines. I'm just pointing out that there are limitations to UOA's. "Cautious" is the right word.
All analytical methods have limitations. This is true about analyzing oil, water, blood, martian soil, global temperatures, radiation from the big bang, or anything else you can think of.
 
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 Originally Posted By: saaber1
I think Pablo said it best by saying we need to be "cautious" when using UOAs as a measure of wear. The UOA without particle analysis may catch wear or it can miss it entirely. IMO, it is probably not wise to say UOAs "always" are a measure of wear and it is not wise to say UOAs are "never" a measure of wear. It is probably better to say it "can be" useful to indicate wear and the more information we have, such as expert analysis, good trending, etc. the more useful it can be in this regard. I think in general we all like to see lower wear/contaminant metals than higher. I recently posted an example of a cam follower that failed in a 2.0 SI engine and there was no trace of evidence in the UOA trends for that car. Here is a counter example of the same engine with exactly the same problem where a UOA clearly showed something wrong (on a side note, this UOA is one of the "outliers" that RL_RS4 correctly identified as an engine with a problem after I posted the revised ppm FE/1000 miles graph for the UOAs we have on this engine a few months ago, but I only learned of the engine problem last week):
 Originally Posted By: corradokidg60
...Here's my Blackstone oil analysis for 40k miles worth of changes (4) - the last oil change shows metals in it because I later found out I had the dreaded HPFP/intake cam/cam follower wear issue. \:\(
So again, I think being "cautious" is the key.
I'm sorry about his engine, but it's nice to see that the science of UOA was able to predict the problem. Unfortunately the owner drove 10K more miles than he needed to and scored the bearings. The problem was predicted by the UOA at 18,981 miles.
 
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