Originally Posted By: chrisri
Wear numbers are perfect. Personally, I would extend OCI to 7.5k miles for convenience.
Wear numbers are perfect?
Did I miss something? Where are the trends to compare against. Without those how on earth can you conclude perfect wear numbers. 2 used oil analysis and you can conclude "perfect wear numbers"
Do you have any idea just how ridiculous that sounds.
Firstly 10 ppm is nothing. Literally nothing so if you are trying to imply that if these "wear rates" were 10ppm higher,which is nothing,is that imperfect.
It's truly absurd to believe that without data trends a person can compare a couple used oil analysis and conclude perfect wear. It's beyond absurd actually m
No 2 vehicles are operated identically. Heck the same person can drive differently depending on mood so on that we CAN conclude that engines will shed metal differently based on how it's operated.
So that tidbit of info right there means comparing wear rates between 2 different engines,even if the engines are built exactly the same,excludes comparison because test conditions aren't consistent.
So comparing 2 used oil analysis from 2 different cars is a fools errand and nothing can be gleaned in relation to wear and the differences in "wear rates".
I don't understand why so many here just cannot comprehend that you cannot compare wear rates on 2 different,but identical vehicles. Trying to infer something by making that comparison shows a total lack of understanding of what a used oil analysis is actually for,monitoring tbn and contamination.
Not wear.
Yes,after 4 or 5 used oil analysis you can start working out averages and typical values for YOUR PARTICULAR ENGINE,but those values are meaningless if trying to compare them against a different vehicle.
Only once a trend is established can one compare an anomaly and if that anomaly becomes the trend only then can one make an informed "guess" that there's a problem.
For example
5 used oil analysis come back all with wear metals within 10ppm then you get one that is high 20ppm with lead.
Now we monitor that lead. If it stabilizes then we can conclude normal wear for THIS PARTICULAR ENGINE. If it returns to the previous mean value hen we can conclude particle streak,if it consistently increases we can conclude bearings.
Now this particular engine may have higher wear values when compared to a different,indentical vehicle however that doesn't make it abnormal nor does that mean the engine won't last as long. All it means is this particular engine wears in this particular way. That is all.
This isn't voodoo nor witchcraft yet guys here take various used oil analysis from different,but similar vehicles,compare against theirs then conclude one engine is wearing less than the other which is utter nonsense.
your comment of "perfect wear" is absurd because it doesn't exist.
It's a unicorn. There is no "perfect wear" for all.
There might be "perfect wear" for this particular engine but that cannot even be considered until there is enough data to compare against itself.
Voodoo is voodoo. The occult is the occult. A used oil analysis is a tool used to measure the properties of a lubricant and compare those properties against condemnation points,and to monitor contamination which can expose coolant leaks and intrusion as well as insols which can expose air filtration defects.
They are not a guide to be used like a report card that you compare against someone else's report card,then assuming because the students have the same grade that they both know the exact same amount in each course and have the same weaknesses in others.
2 students pass the 5th grade with identical overall mark of 85%. Now each student has different grades in the various subjects but their averages are the same.
Comparing 2 used oil analysis from different vehicles is like saying those 2 students,because they have the same grade have the same grades in every subject and if tutored will require the exact same tutoring,when the truth is each student is different and therefore does everything a bit different.
Engines are the same. Yes they are the same,within tolerances,as every engine that came off the assembly line before it,and the same as the ones after it however they aren't exactly the same,nor are they operated the same so they will wear differently.
Even if the wear rates from 2 identical engines were the exact same without measuring any components a person cannot conclude the wear metals came from The same place moving parts.
its nonsense to conclude wear can be compared in this way and absurd to conclude this is "perfect wear" as though such a thing exists in the way that all engines can be measured and a benchmark exists.
What is perfect wear. Who says how many ppm is acceptable and how many is too much. Where is the line. Did the oem establish this line. If just 1ppm over really that bad and will failure be imminent.
I hope you begin to actually understand why