SAE Paper on shear stability under high speed/load

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Interesting paper, as it covers a number of memes on BITOG
* you need to run two identical engines on different oils to do a meaningful test;
* how do Buick 3.8s fare on different viscosities;
* UOA versus teardown results;
* VII versus deposits;
* High shear viscometry versus Kinematic
* Viscosity versus economy.

What the paper offers...
* same basestock and additives, 4 different VIIs brewed to same KV100;
* 4 identical engines;
* that happen to be Buick 3.8s;
* includes teardown, and touches on UOA;
* looks at deposits with shear stable and non shear stable VIIs;
* recommends gradings based on HTHS;
* touches economy briefly.


http://papers.sae.org/780982/

Quote:
Four multigrade engine oils, containing the same base oil plus SE additive package but VI improvers of differing shear stability, were evaluated in 80 000 km of high-speed, high-temperature vehicle service.

Bearing, piston ring and valve guide wear, as well as oil consumption, oil filter plugging and engine cleanliness were all worse for the engines operated on the low-shear stability oils. The wear differences were traced to differences in high-shear-rate viscosity, while the cleanliness, filter plugging and oil consumption differences occurred because of excessive wear or polymer shear degradation.

These results suggest that engine oil viscosity should be specified under high-shear-rate conditions.


Here's a google books that delivers most of the paper.
 
Originally Posted By: used_0il
Why do you do this to me every night?



Ha.
Because it's daytime where he is.


Thanks Shannow. I've gotta check out the links and read the info. If not I fear you'll give up on us and quit posting them.

Thanks Shannow. I'll sleep later.
 
Awwwwwwwe man. 25 bucks.


Is there a cliff notes version,perhaps condensed and therefore closer to my allowed budget of free?
Hehehe.
K. To the Google books version.
 
9PM Saturday night here...sorry used_Oil

Clevy, am scouting around for a PDF version, will link it if I find it.
 
Thanks Shannow. It would be great if you can get it in PDF.

That one quote alone could start a ten-page thread.
 
Originally Posted By: Turk

February 1st, 1978......




Considering 1978 Oil and todays are like night and day a retest is needed.
More stable oil less wear TGMO wins again LoL.
 
I'll open a thread as soon as my ARCO GRAPHITE 10W40 SE fill (oil from 1979) gets 5k miles in my Fiat Punto 2014 1.4 flex fuel (fed only by 87 E25 gas). Looks like is was way beyond its time oil. It could pass later API classifications, easily, IMO. I still got 5 quarts left of the stuff ...
I won't go to 10k miles usage on these though, as per manual.
 
Last edited:
Originally Posted By: Turk

February 1st, 1978......


I take it that you read more than the date ?
 
You can read part of the paper using the "Preview Technical Paper." They used rod bearings to measure wear. The very end of the preview says:
"The results in Table 5 indicate that the wear with the two shear unstable oils (B and D) was twice that with the two shear stable oils..."
 
At the risk of being simplistic, this seems to be more evidence (maybe circumstantial evidence, but still..) in support of my use of straight 40W oil in my car.

This was originally an "emergency" response to a serious oil leak, but I might have to adopt it as a policy.

As I understand it, they aren't claiming to precisely reproduce the performance of any particular oil, but the VI improvers in their formulations are in commercial use, so they may mimic some commercially available multi-grades.

Since I'd guess it won't be possible to find out which commercially available multi-grades (if any) don't show significant VI shear, it might be better (for me, in Taiwan) to avoid them altogether.
 
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