Originally Posted By: used_0il
Good grief, the post wasn't directed at you, but at using UOAs to determine engine wear, and the people who promote the notion.
You will not see contrasting results in a UOA from using one grade instead of another, unless one or the other is totally out to lunch.
That is why repeating the same experiment over and over again expecting a different result is an indication of what?
Go look in the motorcycle UOA threads and show me clutch material or flakes of metal from the transmission.
The purpose of a UOA is to determine the suitability of an approved lubricant to remain in service or not, and to identify small mechanical problems before they become big ones.
The roll of a uoa is not for conducting research into grade recommendations when it already has been done by the manufacture beyond personal experiments and amusement.
You're half right, and half wrong.
Yes - UOAs are used as a direct view of lubricant health. That is true. But lubricant health is an input into the health of the equipment.
UOAs are a great, inexpensive means of viewing equipment health, and if you doubt that, then please explain why there is an entire industry based on this concept. Please tell us why you believe that Polaris, Blackstone, etc are all wrong. Please ring up Terry Dyson on the phone and explain to him why you think UOAs cannot predict engine health. Please explain why multiple SAE studies have improperly shown correlation between UOAs and other means of ascertaining wear (mass weight analysis, ion bombardment, etc).
Is a UOA flawless? Nope. There are things that will escape a UOA, such as particles that are larger than 5um. But any event that sheds metals that huge are probably catastrophic, and a UOA is the least of your worries at that point.
Are there other means of predicting wear? Sure. You can tear down your engine and measure clearances; that's kind of time-consuming and expensive, don't you think? While probably more accurate than a UOA, it's also impractical for the average guy. Not to mention that every time you disassemble and assemble the engine, there are risks involved there, too. And even when you measure the clearance in this method, there are margins of error in gage R&R, etc. This method is a tool like any other; there are pluses and minuses.
UOAs are good predictors of engine health. They are not perfect, but nothing is. They are a very low-cost, easily attained view of the equipment status. If you choose not to use them as such, then fine by me. But don't pretend like they are useless or otherwise foolhardy. That's a very close-minded view.
And to your implication that UOAs cannot be used for selection criteria is also limited. Macro data analysis is a proven methodology used in just about every mass production industry in the world today, from lubes to the power-vehicle industry to mining to potable water to toothpaste and every concieveable product in-between. I challenge you to show me an industry that does not use macro data analysis in mass production.
I agree that you're not going to see any statistical difference in grades in terms of wear control. That is EXACTLY the point. There is typically no difference whatsoever. Grades are typically recommendations, not live-or-die mandates. Your supposition is that UOAs cannot discover the performance differences between grades. Did it ever occur to you there simply isn't one to discover? That the proof is in the absence of differential, not the ignorance of it?
Please explain why you believe that UOAs are not a good predictor of equipment health, why you think the entire industry is wrong, and cite your specific examples of where UOAs failed to predict wear but some other methodology prevailed in the very same situation. Feel free to link specific SAE studies that counter those that already exist showing good correlation between UOAs and other methods.
I challenge this quote from you:
Quote:
Why run 10W30 then perform UOAs just to prove a point, when 5W40 is a superior winter oil and 15W50 is a far better summer oil?
Just how is it that 5w-40 is "superior" in winter and 15w-50 "far better" in summer. In terms of what? What criteria are you measuring? Looking at a lube's characteristics is only a prediction of potential for protection. Conversely, UOAs show how the lubes actually did their job in terms of wear. So when wear data shows there is no difference, then by what means do you declare something "better" or "superior". That is lube bigotry in it's purest form!
If I understand your contention correctly, you believe that UOAs can only show a reasonable view of the lube health and not equipment health. If this were true, then what lube limits are shown to have ACTUAL EFFECT on the equipment? How does one know? IOW - if I am to accept that ONLY lube health is indicated in a UOA, then what proves the chosen condemnation points are valid? How do you know that Vis of X value is OK, but value Y is not? How do you prove that fuel contamination of value P is OK, but when it rises to value Q, it's detrimental? These are all INPUTs to a condition that we seek to know. We want to know how an engine is wearing, not how the lube is doing. Lube health is a predictor of equipment health, and nothing more. I want to know OUTPUTS, I want to know actual wear. And while UOAs are not a perfect view of equipment wear, they are, by far, a reasonably accurate, very low cost, easily attained view of general equipment wear. Lube health is only a view of a fluid. Wear metals are a view of mechanical degradation.
My UOA study clearly shows correlation between the data and the field. There are SAE articles to back this up. Everything points to UOAs being a reasonable, cost effective means of predicting equipment wear. What do you have to prove otherwise?
We shall continue to agree to disagree.
