Originally Posted By: Kuato
How so? Why is a teardown required to validate results?
Because you have no results without a teardown. You have numbers on a sheet. You are familiar with the fact that a UOA samples an extremely narrow range of particle sizes right?
Quote:
With that logic any UOA is worthless, and that just doesn't fly.
The purpose of a UOA is to determine lubricant life and contamination levels, not monitor engine wear. They are not a wear determination tool. Using them in that manner is nothing short of foolhardy.
Quote:
I've had more than 10 UOAs on this vehicle with 7 different oils. 5 of these UOAs were at 5000 miles with the same driving, same filters and same time of year. 4 of the samples came back with a max of 20ppm Fe. The M1 came back with 49. Other oils tested included ST Syn, ST, Amsoil and VWB.
It has been conclusively shown by multiple UOAs across multiple vehicles without exception that M1 in the Jeep 4.0 is contraindicated due to accelerated wear. Like I said in my earlier post, M1 is a great oil. But it's a poor choice for the 4.0.
Prove accelerated wear. That's the issue here. You assume higher PPM for a given lubricant means accelerated wear. It doesn't. That's why we do tear downs, because measurements are real results.
Please read:
http://www.bobistheoilguy.com/used-oil-analysis/
Then see this thread:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1325382
Cheater note, this liner has 1.2 million Km's (745,000 miles) on it with the condemnation point for Fe at 150ppm
Originally Posted By: Doug Hillary
Information:
Operation = Interstate, Linehaul,Reefer - one Driver for life,
Typical use per annum = 225kkms
Detroit Diesel 12.7ltr Series 60 @ 500hp, 1650lb/ft @1200-1525rpm
Cruise revs 1650rpm, Max revs 1800
Donaldson ELF Filters + MannHummel Centrifuge
Lubricant = Delvac 1 5W-40 (from 60kkms)
OCIs
Average = 99711kms
Longest = 116227kms
Data
Soot
Average @ OCI = 3.2%
Highest @ OCI = 7.8%
Iron
Average @ OCI = 134ppm
Highest @ OCI 221ppm
Highest TAN @ OCI = 6.13
Lowest TBN @ OCI = 2.26
Centrifuge uptake rate = 0.0029g/km
Oil consumption averaged almost exactly 6kkms/ltr
The two major condemnation points were soot (3.5%) @ iron (150ppm) - viscosity was always near new
I hope this is of interest
That's an average OCI of 62,000 miles. An average Fe figure of 22ppm per 10,000 miles.
How many OCI's did you track the AFE for? Did you establish a legitimate trend or did you assume that the 49ppm meant epic engine failure and you terminated the "test" at that point?
I had 35ppm of Fe on my M5 UOA. And it has alumasil cylinder liners. I'm not at all concerned and neither was the lab because the condemnation point is 100 PPM. A man who has probably done more UOA's than everybody on this board combined (Doug) who also happens to be the author of that article I mentioned earlier also wasn't concerned by it.
Yes, there's an undeniable psychological factor at play here and that is that we want to be able to do "right" by our engines. So believing that we can do just that by performing UOA's and finding the oil with the "lowest wear" fits that agenda. We "enhance" the purpose of the tool, instilling it with this mystical gift of wear prophecy, but most of us don't even bother to get particle counts done, which is about the most useful thing regarding wear that a UOA can tell you. That's why when REAL tests are being done they employ random-sample tear-downs (like Doug did......) because in order to actually track wear, you need to measure and observe components. A UOA doesn't tell you that. If it did, Doug wouldn't have needed to pull those bearings or liners now would he?