Fresh Oil = Stripped AW ???

[KrisZ]

Originally Posted By: demarpaint
Originally Posted By: Phishin

There will always be microscopic deposits. Always. I don't care what oil you use or how short of an OCI you have, there will always be wear and there will always be deposits. No oil's high level of detergents are going to prevent acids from being present (detergents NEUTRALIZE the acids, not prevent them....therefore acidic byproducts cannot be totally avoided, but their quantity can be diminished with high levels of detergents), and no amount of dispersants is going to carry away all of the deposits. Therefore, as deposits form, there is always a chance that the deposits will contain wear metals present in the oil.

I'd be willing to bet if someone was crazy enough to change their oil every 500 miles in a new car (so deposits, varnish, and wear metals are at a steady state), after the break-in miles, you wouldn't see all these "spikes" anymore.


Well stated. The second you turn the key there'll be wear, combustion by-products, etc. going into the oil. Replenishing the oil with fresh new oil will do some cleaning. Don't forget there is always old oil remaining in the engine with deposits etc. in it, which you'll never get out when you change the oil. Depending on the engine and sump capacity it could be quite a bit. That oil instantly mixes with the new fresh oil, any wear metals in that old oil is tossed instantly into it. Combine that with some additional cleaning from the fresh oil, and guess what......
I'd like to see the results of the 500 mile crazy OCI you mentioned, I wonder if it has ever been done?



Didn't Phishin say?
Quote:
...So, detergents aren't really doing any cleaning. They are prevent deposits from forming...


IF the above was all true, all engines no matter what type of oil and at what OCI, would have heavy deposits at high miles. We know that it is not true. The trucking business would not be able to rack up millions of miles on their engines and even the grocery getters would suffer from excessive deposits because per the above theory, the oil would not clean up anything, but only neutralize the acids, so the buildup would continue to grow with miles.

This brings up another point. IF the initial spike of wear metals is caused by the left over deposits and left over oil, why does it decrease through the OCI and then spike again when the oil is changed? Again, using the above theory, (oil doesn't clean, only neutralizes) the deposit build up and wear metals would be on an ever increasing slope since the detergents would be less and less effective for neutralizing the acids and there would be left over deposits and wear metals from previous OCIs.

In other words, every consecutive OCI should show more and more deposits and wear metals because of the accumulative effect, again per the above theory, but we all know that the UOA numbers (accuracy is largely irrelevant here, but repeatability is) stay pretty much the same for every oil change done at the same interval.

 

[Phishin]

Originally Posted By: KrisZ

Didn't Phishin say?
Originally Posted By: Phishin
...So, detergents aren't really doing any cleaning. They are prevent deposits from forming...


KrisZ,

You didn't read what I said very well. Yes, that is what I said. BUT, I also said dispertants carry the deposits away. They are the ones that keep deposits from "sticking" to your engine internals.

In reality:
Detergents - Neutralize Acids
Dispertants - Carry deposits away/keep them in solution
Both Detergents and Dispertants (including their cations) contribute to both Acid Neutralization and keeping deposits into solution. But, they mostly do one or the other, with minor contributions to the other facet.

Your whole post made assumptions that I said certain things, and I didn't.

 

[TrevorS]

Does everyone think dnewtons conclusions from his statistical UOA study are incorrect also?

 

[KrisZ]

Originally Posted By: Phishin
Originally Posted By: KrisZ

Didn't Phishin say?
Originally Posted By: Phishin
...So, detergents aren't really doing any cleaning. They are prevent deposits from forming...


KrisZ,

You didn't read what I said very well. Yes, that is what I said. BUT, I also said dispertants carry the deposits away. They are the ones that keep deposits from "sticking" to your engine internals.

In reality:
Detergents - Neutralize Acids
Dispertants - Carry deposits away/keep them in solution
Both Detergents and Dispertants (including their cations) contribute to both Acid Neutralization and keeping deposits into solution. But, they mostly do one or the other, with minor contributions to the other facet.

Your whole post made assumptions that I said certain things, and I didn't.



Quite contrary, I read your post very carefully. You're assuming that it's a zero sum game when the detergents in oil don't clean anything, just neutralize acids and the dispersants ensure that any contamination produced is suspended in oil and no deposits are ever formed in the engine. But we all know it is not true. Deposits do form even in healthy and new engines and if your theory were true, all those engines would eventually sludge up.

 

[CATERHAM]

Originally Posted By: edhackett

Another thing to take into consideration when viewing the SAE paper is that as a bench test, the fresh oil never sees combustion products. In your car the oil is diluted typically 10-15% with used oil and sees fresh combustion products as soon as you turn the key.

I really wish the authors of the SAE paper had run aged motor oil on a new cam/lifter as a control. All I will say about that paper in general is that if I had submitted that paper to my boss with the rather incomplete methodology section, integrity of the aged oil in question, and figures that did not match the text, my behind wouldn't likely ever grow back.

That said, the paper does provide useful data on the differences in anti wear between new and aged oil, and that 15K oil is still capable of maintaining an effective anti wear layer. The oils themselves were not capable of 15K. All were showing signs of distress (TBN/TAN) at 10K and by 15K one of these 5W20s was a XW-50 and the other two XW-40s, and TAN was 2-3X TBN. Sludge City!
Ed

Thanks to Jim Allen I've had a chance to review the paper as well and found it highly flawed.
Why they even bothered to test used oils that had turned acidic and were clearly not suitable for continued use is beyond me.
All oil samples had shown signs of oxidation by 5,000 miles and even by 3,000 miles in the case of the 500 ppm ZDDP sample.

By 3,000 miles the wear rate was "practically zero" in all samples so why didn't they test at 2,000 miles, 1,000 miles and even 500 miles to determine when the wear rate dropped to "zero"?
It should also be noted that they mentioned that while the wear rate of the fresh oil was higher "its absolute value is still quite low and quite acceptable."

Bottom line IMO, yes dispersants and detergents can affect boundary lubrication but we've always known that and it's affect is limited and acceptable. There are lots of reasons to run very short low mileage oil change intervals. For example, 500 miles can be too long if you're only driving 2-3 miles/day in sub-freezing temp's which could take one more than 6 months to do.

 

[edhackett]

CATERHAM,

They didn't run the lower milages, because the paper wasn't about the formation of the layers, the scope of the research was to evaluate valve train wear at various normal to extended intervals, how long can you go before valve train wear is an issue. My wish for different controls and your wish to see the wear pattern at low milages are outside the requirements for the core of the paper. It shows some interesting things, and had they done a more comprehensive experiment, more information could be obtained. Unfortunately this wasn't a PhD dissertation, so we can't send them back to do more.

I also want to clarify for those that don't have the paper that the wear that they classify as "quite low and quite acceptable" is referring to the new oil and new lifter, not the 232% lower wear rate of new oil and a conditioned lifter.

Looking at the UOA data, what do you think of the advice often given on BITOG to those with lowish, but still above certain condemnation points and no TAN data to keep running the oil, TBN depletion isn't linear?

Ed

 

[edhackett]

I've wondered where the idea that fresh oil additives remove the previous layer comes from. The following is from the introduction of the SAE paper and may be the root of that "myth".
Quote:
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 phosphorous concentration (2). Film thickness is also dependent on oil temperature with higher temperatures tending to promote greater film thickness (3). However, when a dispersant is added, the film is removed and the film thickness stabilizes at a lower value.


Once again this was a bench test done on non fully formulated oil.

The anti wear film formed by a fully formulated oil is not removed by fresh fully formulated oil.

There's been a lot of Shanow's "taking actual data from an actual test, then misapplying the outcomes to a logical fallacy…" concerning this and similar papers.


Ed

 

[edhackett]

Oops, caught by the edit timer.

I said this: There's been a lot of Shanow's "taking actual data from an actual test, then misapplying the outcomes to a logical fallacy…" concerning this and similar papers.

I don't mean to slight anyone by that comment. Reading scientific papers outside of your area of expertise, understanding the methodology and its limitations, understanding exactly what the data represents, coming to conclusions based only on what the data is telling you, in context, without imposing your own expectations or biases is not an easy task.


Ed

 

[TrevorS]

Originally Posted By: TrevorS
Does everyone think dnewtons conclusions from his statistical UOA study are incorrect also?


Anyone care to answer this?

 

[friendly_jacek]

Originally Posted By: TrevorS
Originally Posted By: TrevorS
Does everyone think dnewtons conclusions from his statistical UOA study are incorrect also?


Anyone care to answer this?


The simple answer is: No, not everyone thinks.

 

[Analyzer]

I think we've gotten away from the initial question posed to us all, being, "People claim that fresh oil strips their engine of AW additives like ZDDP and Moly."

Phishin posted an accurate chemical description of how the detergents/dispersants function within a fully formulated oil. The primary roll of detergents within motor oil is not to breakdown and remove existing deposits, but to PREVENT and NEUTRALIZE combustion byproducts that could lead to sludge/varnish deposits and oxidation. Here is a direct quote with some ancillary background information provided from THE SAE AUTOMOTIVE LUBRICANTS REFERENCE BOOK By: Roger F. Haycock, ‎Arthur J. Caines, ‎John E. Hillier - 2004

"However, in the mid 1930's, the Caterpillar Tractor Company introduced a new range of medium-speed diesel engines for it's earth-moving equipment. These were high-output engines that immediately ran into problems of piston deposits and ring-sticking. After a few hundred hours of operation, engines had lost power and had to be disassembled and the piston rings freed in the grooves. This was done by hand cleaning in baths of oil or solvent, and it is said that some users found cleaning to be easier if "detergents" in the form of metal soaps were added to the oil.

(This may or may not be the origin of the term "detergent" in relation to promoting piston cleanliness , but it is now clear that lubricating oil detergent additives do little to remove existing deposits in an engine, although these may be lost by mechanical means. Detergents as we know them serve not to clean away deposits but to prevent them from forming in the first place by combating combustion-derived contaminants).

SAE Lubricants Book

Furthermore, detergents DO NOT "strip" away anti-wear additives like ZDDP. Now, the given detergents formulated within a given oil can/will compete with AW additives like ZDDP for surface area of various metal substrates, thus inhibiting ZDDP's ability to formulate a thorough sacrificial wear layer, but none the less, ZDDP is not stripped away like a Finish Stripper acting on a painted surface for lack of a better analogy.

Direct Quote: "The consensus is that the efficacy of ZDDPs is retarded through a competition of detergents and dispersants either absorbing on the surface or limiting the interaction between ZDDPs and the metal,3,18,19"

Chemical and Mechanical Analysis of Tribofilms from Fully Formulated Oils Part 1 By:
G. Pereira1, A. Lachenwitzer1, M. Kasrai1, G. M. Bancroft1, P. R. Norton*1, M. Abrecht2, P. U. P. A. Gilbert2,3, T. Regier4, R. I. R. Blyth4 and J. Thompson1-2007 (also quoted previously by Shannow)

Lastly, as far as increased wear amounts for recently changed oil I agree with dnewton3 statistical analysis that the increase in wear can be attributed to either the new oil being introduced presenting more "competition" to ZDDP thus inhibiting its ability to form a boundary layer thus increasing wear minutely, or the remaining oil from the previous oil change remaining in the vehicle thus increasing the wear contaminants. Even though the study discussed earlier does indicate higher wear levels ( and thank you Ed for further clarification on the SAE paper for those of us that don't have the ability to view it) after initially changing the oil are minute in nature; MY personal opinion would be that the 10-20% of oil remaining from the previous oil change according to Ryan Stark of Blackstone Labs is probably the largest contributing factor to the initial wear material spike due to there being close to half a quart or more of remaining oil now being circulated with new oil.

http://www.bobistheoilguy.com/used-oil-analysis-how-to-decide-what-is-normal/

 

[Analyzer]

My bad, ran out of edit time before I noticed the typo above, it should have read like this:

Direct Quote: "The consensus is that the efficacy of ZDDPs is retarded through a competition of detergents and dispersants either absorbing on the surface or limiting the interaction between ZDDPs and the metal,3,18,19"

 

[TrevorS]

Thanks Analyzer.

So the potential mechanism for increased wear through frequent oil changes is not putting enough anti wear layer down due to continual competition with detergents.

 

[Analyzer]

Originally Posted By: TrevorS
Thanks Analyzer.

So the potential mechanism for increased wear through frequent oil changes is not putting enough anti wear layer down due to continual competition with detergents.


Yes, that is one of the potential mechanisms for increased wear as shown in the study, but as Ed pointed out earlier the research was conducted with non formulated oils:

"Once again this was a bench test done on non fully formulated oil.

The anti wear film formed by a fully formulated oil is not removed by fresh fully formulated oil."

The oil we are utilizing in our vehicles would be considered a fully formulated oil, and even though competition between the compounds does exist, it further decreases the possibility of this type of wear occurring to even smaller levels.

 

[Doug Hillary]

Hi,

Analyzer - You said this:

"MY personal opinion would be that the 10-20% of oil remaining from the previous oil change according to Ryan Stark of Blackstone Labs is probably the largest contributing factor to the initial wear material spike due to there being close to half a quart or more of remaining oil now being circulated with new oil.'"

I've been very hesitant in contributing to this Thread for a number of reasons. That said however, and in my experience in this field, the above quote is the most meaningful - and certain other factors apply to this too.

Remember that unless "simple" UOAs are rigidly trended in a comprehensive manner and VOAs are also known, they are quite unreliable in wear measurement

More comprehensive wear rate measurement techniques and practices are available and are used by Manufacturers

 

[TrevorS]

Originally Posted By: Doug Hillary
Remember that unless "simple" UOAs are rigidly trended in a comprehensive manner and VOAs are also known, they are quite unreliable in wear measurement

More comprehensive wear rate measurement techniques and practices are available and are used by Manufacturers


The above is why I've asked people to comment on dnewtons statistically significant UOA study.

 

[demarpaint]

Originally Posted By: Doug Hillary
Hi,

Analyzer - You said this:

"MY personal opinion would be that the 10-20% of oil remaining from the previous oil change according to Ryan Stark of Blackstone Labs is probably the largest contributing factor to the initial wear material spike due to there being close to half a quart or more of remaining oil now being circulated with new oil.'"

I've been very hesitant in contributing to this Thread for a number of reasons. That said however, and in my experience in this field, the above quote is the most meaningful - and certain other factors apply to this too.




I said something similar earlier in the thread, it made sense to me then and it still does. Now factor in not changing the filter and that % of used oil remaining in the sump is even higher. I'm glad we agree.

 

[TrevorS]

I think what you said is quite different to what Doug is saying.

Originally Posted By: demarpaint
I read here a while back that the fresh oil with the fresh add pack does some cleaning of deposits that accumulated during the prior OCI. That cleaning frees up wear metals that might have been trapped in those deposits. That could be the cause for a slight spike in wear metals early on in the OCI. That also made sense to me.

 

[demarpaint]

I decided to toggle this morning, I said this too:

Originally Posted By: demarpaint

Replenishing the oil with fresh new oil will do some cleaning. Don't forget there is always old oil remaining in the engine with deposits etc. in it, which you'll never get out when you change the oil. Depending on the engine and sump capacity it could be quite a bit. That oil instantly mixes with the new fresh oil, any wear metals in that old oil is tossed instantly into it. Combine that with some additional cleaning from the fresh oil, and guess what......

 

[TrevorS]

If somebody here is already doing UOAs that give comparative wear rates for different oci intervals, then for $10 to $65 we could figure out the impact of the residual oil.

At next oci, sample some cheap oil ($10) and set aside to send for a VOA ($25).

Change oil with this cheap oil and run engine for 5 minutes.

Drain oil and send off for a UOA ($25).

Fill with the regular oil and carry on with UOAs.

The new oil will now have minimal residual wear metals in it.

The VOA and UOA on the flush oil will indicate how much wear metals were left after draining oil.

You could even skip the VOA and UOA on the flush oil but still go ahead with the flush. The UOAs on regular oil with and without flushing can then be compared.

The flush oil could even be reused in another vehicle making this a zero cost study for someone already trending UOAs.