Originally Posted By: 2015_PSD
Originally Posted By: fdcg27
First off, what you might find in the FF of any engine is of no significance.
There will be some residual machining debris as well as wear-in particles.
FF UOAs typically feature horror show metals levels which are really of no concern at all.
Remember that we're talking about parts per million here so a small absolute difference looks huge.
Now, can you get more accurate results for various particle sizes?
Yes, you can pay more to have particle counts done.
You'll see a few such UOAs in that forum. Not many, since this does involve a fair bit more money, but it can be done and those UOAs can be viewed.
Remember too that UOAs are mainly useful as a measure of oil condition and can be used to help determine appropriate drain intervals. They aren't really a good tool for measuring engine wear.
Also, some engines shed very little metal while others normally shed a lot.
If you compared a UOA from an SBC with one from a four cylinder timing belt Honda, you'd swear that the Chevy was in its death throes. It wouldn't be since it simply normally sheds more metal.
For clarity, I am thinking past the FF, but it is a great example of the theoretical weakness of a UOA and yes, I am aware they cannot be reliably used to measure wear, but what I am suggesting is that with a few fundamental changes could they be? Also, the PPM reading is based upon certain sized particles--the ones which may actually need to be counted may not be in the PPM reading. I have done several particle counts and I am not sold on that as a way to measure wear either since they simply place a sharper lens on the same results already taken. I am not saying you are wrong by any stretch, but I am thinking quite a bit out of the box.
Okay, we're on the same page now.
I guess the question would be how one might use this information and how significant the differences between the best and worst oil in the required grade and spec might be in wear performance. I'm guessing that the difference would be small enough as to be lost in the statistical noise.
We both know that there are a range of desirable qualities to be found in any group of oils in any given grade meeting any spec. You like low volatility and good cold end numbers? Me too. Do you also value high solubility and polarity? I do as well, the problem being that you may not be able to achieve the former in company with the latter. I guess what I'm saying is that every fully formulated oil is a compromise of characteristics and cost and cost is a legitimate consideration unless you and I want to pay ten bucks a quart for oil. I know that I don't want to.
Also, how many engines have you actually worn out with any oil?
I've not actually worn out a single one myself.
There are absolutely cases in which the wear tea leaves found in UOAs can be used to diagnose engine problems before they become fatal. Certain BMW engines signaled an urgent need for bottom end work with increases in copper while certain turbo Subarus would do so with detectable levels of silver. In both cases, the engines were saying that the bottom end should be torn into and the main and maybe rod bearings replaced before a bearing spun.
We all know what increasing sodium means, unless we're using old-school API spec Valvoline (or RP) in which case we'd look for increasing potassium.
Your idea is an interesting one and it would be fun to see some of these enhanced UOAs. I'm just not sure what the practical application would be.
Originally Posted By: fdcg27
First off, what you might find in the FF of any engine is of no significance.
There will be some residual machining debris as well as wear-in particles.
FF UOAs typically feature horror show metals levels which are really of no concern at all.
Remember that we're talking about parts per million here so a small absolute difference looks huge.
Now, can you get more accurate results for various particle sizes?
Yes, you can pay more to have particle counts done.
You'll see a few such UOAs in that forum. Not many, since this does involve a fair bit more money, but it can be done and those UOAs can be viewed.
Remember too that UOAs are mainly useful as a measure of oil condition and can be used to help determine appropriate drain intervals. They aren't really a good tool for measuring engine wear.
Also, some engines shed very little metal while others normally shed a lot.
If you compared a UOA from an SBC with one from a four cylinder timing belt Honda, you'd swear that the Chevy was in its death throes. It wouldn't be since it simply normally sheds more metal.
For clarity, I am thinking past the FF, but it is a great example of the theoretical weakness of a UOA and yes, I am aware they cannot be reliably used to measure wear, but what I am suggesting is that with a few fundamental changes could they be? Also, the PPM reading is based upon certain sized particles--the ones which may actually need to be counted may not be in the PPM reading. I have done several particle counts and I am not sold on that as a way to measure wear either since they simply place a sharper lens on the same results already taken. I am not saying you are wrong by any stretch, but I am thinking quite a bit out of the box.
Okay, we're on the same page now.
I guess the question would be how one might use this information and how significant the differences between the best and worst oil in the required grade and spec might be in wear performance. I'm guessing that the difference would be small enough as to be lost in the statistical noise.
We both know that there are a range of desirable qualities to be found in any group of oils in any given grade meeting any spec. You like low volatility and good cold end numbers? Me too. Do you also value high solubility and polarity? I do as well, the problem being that you may not be able to achieve the former in company with the latter. I guess what I'm saying is that every fully formulated oil is a compromise of characteristics and cost and cost is a legitimate consideration unless you and I want to pay ten bucks a quart for oil. I know that I don't want to.
Also, how many engines have you actually worn out with any oil?
I've not actually worn out a single one myself.
There are absolutely cases in which the wear tea leaves found in UOAs can be used to diagnose engine problems before they become fatal. Certain BMW engines signaled an urgent need for bottom end work with increases in copper while certain turbo Subarus would do so with detectable levels of silver. In both cases, the engines were saying that the bottom end should be torn into and the main and maybe rod bearings replaced before a bearing spun.
We all know what increasing sodium means, unless we're using old-school API spec Valvoline (or RP) in which case we'd look for increasing potassium.
Your idea is an interesting one and it would be fun to see some of these enhanced UOAs. I'm just not sure what the practical application would be.
