Originally Posted By: Shannow
Originally Posted By: dnewton3
Clearly some of you have never actually paid for and read the SAE 2007-01-4133. It clearly speaks to the TBC and how it affects wear, as well as the degradation of it upon fresh OCI, it's development over an OCI, and the magnitude due to oxidation (most specifically the application of heat) of the lubricant. Also, not only are wear rates reduced, but frictional drag is also reduced by the TBC. Obviously, they do go hand in hand to a large degree. But the TBC can actually contribute to a reduced parasitic drag.
You're obviously talking to someone else, as I've got the paper.
Originally Posted By: dnewton3
Purchase and read 2007-01-4133.
Collect and analyze more than 12,000 UOAs.
Don't talk to me about theory of lube properties; show me real world data that proves it matters.
Belligerence doesn't help your argument...
As I said, I've got the paper, have read the paper, and as I have repeatedly stated in multiple threads on the issue (including to yourself), you are reading the paper in light of what you WANT it to say, not what it actually offers.
Allow me to quote the SAE study in support of my statements:
Note - I want to be careful here and not reproduce the entire study word-for-word by violating copyright issues, so I'll try to be brief. The ENTIRE article is a great read, and if you truly own it then I don't understand how you cannot see the alignment of my statements and the study data ...
- Fujita et al demonstrated that the thickness of the lubricant-derived film increases steadily with test duration and stabilizes at the 50-100 nm level. The thickness is almost independent of phosphorus concentration. Film thickness is also dependent upon oil temperature with the higher temperatures tending to promote greater film thickness. (page 3, par 2; referring to the TBC film and not viscosity boundary)
- (entire paragraph 2 of page 4 indicating the historical view of previous SAE studies regarding wear and film barriers; denotes the lack of concentration on the topic of time/aging of the oil, etc; too long to quote)
- The wear was measured … by the surface layer activation technique … by bombarding by a proton beam in a particle accelerator (page 6, par 1)
- It is clearly seen that the fresh oil exhibits a much higher wear rate than the vehicle drain sample … The wear rate dropped significantly with the 3000 mile drain oil, in fact the wear rate became practically zero. (page 6, par 5)
- It is interesting to note that the viscosity of the 7500 mile drain oil is about 20% higher (at 100C) than that of the 3000 mile drain oil and therefore, might be expected to show a lower wear rate because of the increased film and the resulting reduction in asperity contact. But both oils showed similar wear rates indicating that wear rate is controlled more by the chemistry of the surface film formed at the contact than asperity contacts (page 6, par 5)
- The frictional torques continued to drop as the oil aged in the vehicle. The drop in friction torque with the 7500 mile drain oil is about 9-12% compared to when the oil was fresh even though viscosity increased. (page 7, par 1)
- The viscosity of drain oils increased progressively as drain interval increased from 3000 miles to 15,000 miles, but the wear rate of tappet shims and frictional torque did not change appreciably indicating that the reduction in wear rate and friction is related to changes in oil chemistry with aging (page 13, par 6)
The study notes, and makes a specific point in page 4, par 2, that all previous studies by other groups were limited in that they did not focus on the effect of TBC in relation to time exposure (OCI duration). Previous studies were only conducted with same-age lubes, and therefore a static viewpoint was the only thing gleaned. And most all of those tests were only done with fresh oils, not aged as real world use presents itself. Therefore this 2007-01-4133 study is unique in that it looks at the TBC as it ages, and then compares/contrasts the effect of the TBC to the other potential effect of vis.
I have stated, and continue to state, that the TBC controls wear more than the vis. I state that the TBC is improved with heat and age. I state that the wear rates drop as the OCI increases. All of this is supported both by my data and the SAE study I quoted.
I also insist that the wear at start up is not greatly controlled by the oil film because it is simply not present in a productive, meaningful manner upon the first revolution of the crank, until enough volumetric flow exists to supply that hydrodynamic wedge as the pump gets oil to where it needs to be. However, the TBC is present at ALL times, and coats the surfaces with the layer that averts metal-to-metal contact at that critical time. Admittedly this was not part of the 2007-01-4133 study; this is my assertion only. If this is the only thing you find unpalatable then I'm willing to debate this in theory. It is fairly simple to understand my position, is it not? After being established, the TBC is present at all times, during start up and at warm up and at full temp operations. The film boundary layer can ONLY be present once the oil pressure supplied by the pump gets the parts to float on the hydrodynamic oil film wedge; after several revolutions of the crank. How can oil wedge be a part of something when it's not even present? Does the SAE article specifically address this? No it does not. Does it have to? I'd like to think that any sane person understands that for something to have an effect, it first has to be present. After being established, the TBC is assured to be there even before the first degree of crank rotation. The oil pressure wedge isn't present until several revolutions have passed. Is it not self-evident? One thing is present at all times, while another is only present after pressure builds. By default, the wear protection must obviously be provided by something that is present, not something that only shows up later. If you see it differently, then please explain.
I will note that frictional torque as measured in the SAE study is different from pumping losses. As I reread my statements from earlier I have not clearly differentiated this disparity. Pumping losses due to vis increases are not the same as frictional losses at surface contact. However, I contend that the study does prove the TBC to reduce parasitic drag due to friction, but it was not studied regarding vis pumping effects. IOW, the parasitic friction will be reduced as the OCI ages and the TBC improves.
It is also important to understand that as the vis increased over the OCI duration, the wear eventually stabilized at very low levels, ("near zero" per the study) often around the 3000 mile mark. And do recall that other studies proved that the TBC stabilized at 50-100 nm. So the TBC ages and improves and then stabilizes, while the vis is in constant change. And so when the wear rates drop and then stabilize, they reflect the TBC development and not the vis shift. Because vis is always changing (generally getting thicker) but the wear stagnates, vis cannot be said to be the true actor. When you have a variable that changes but the result stays stagnant, then that variable is not having an effect. Wear rate is the result of wear-at-moment, as measure by time/distance. The wear rates drop because wear goes "near zero" as the TBC matures. Once the TBC matures to a full effect, the instant wear is almost nothing. So the "rate" drops as time is added. But the Vis is in flux all the time. If the Vis were the solution to wear, the instant wear would still be affected. A changing variable that shows no shift in result is proven to not be able to affect. So the 3000 miles it takes to stabilize wear is in correlation with the TBC development, but the ever-changing vis cannot make an affect, despite it's ever growing magnitude. If you add more and more of something, but the result does not change, then that characteristic must not be having any affect. And they proved that; wear tracks with the TBC and not vis. And my study data echos that very same phenomenon. Now, I am going to have to expect that you all understand that when I say vis variation, I'm talking about vis shifts within a grade or two. I am also talking about grades that are used within the OEM intended API spec. A 5w-20 SN PCMO and a 10w-30 SN PCMO are not that far apart. But don't construe my statement in such a wild consternation that you think I'm talking about a light sewing-machine lube and a bucket of tar-sand crude ... Don't be stupid. I am stating that using a lube with a grade slightly different from another won't manifest into tangible wear differences. And as the lube vis increases with use, it is proven to have no effect on wear. THAT is what I'm talking about. You see, the SAE study proves that as vis changes in the same OCI, it has no real effect on wear. And my study proves that in field data, regardless of what vis is chosen, wear rates are generally unaffected. So they proved that wear is not controlled by vis in a lab measurement, and I proved it in macro mass-data. Their results and my result concur with each other. Minor grade variation has absolutely no effect on wear rates. Period.
Now, please understand that I am not a chemist; I cannot explain the fundamental elemental aspects that cause the TBC. I can only regurgitate the info as I read it. But I am a statistical process QC engineer, and I have expertise in analyzing real world data and the application of that info into real, consumable information.
If anyone sees it differently, then please show me where my assertions are contradicted by the SAE study. Show me where my micro and macro study data (evidence in my normalcy article) are flawed, and not supported by the SAE article. Because the way I see it, both my UOA study data and the particle bombardment method used by Ford/Conoco exhibit a direct correlation in results, indicating that the two independent study methods reach the same conclusion; that the TBC controls wear more so than does Vis. They proved it it in the lab; I echo it in the real world data. I do not have the money/time/resources to do their type of scientific analysis, but they probably don't bother with macro field data that I can easily access. Two different roads; same conclusion.
What the SAE study clearly states is in concert with what I tried to explain to the OP in his quest to understand if a 10w-30 is going to be as good as a 5w-40 in regard to wear rates.
- both the SAE study and my data analysis prove that vis has little effect on wear
- both the SAE study and my data analysis show that longer OCIs manifest into lower wear rates
- because the SAE study, and all my UOAs, are real-world, field-based experiments, start-up wear is included in the overall wear data
- the SAE study is able to describe and define the chemical nature of the TBC and how it is affected by the OCI; my data study proves their theory is exhibited in real world results
