Blackstone Oil Analysis Viscosity

[Merkava_4]

Why doesn't Blackstone ever recommend a change in viscosity?

When the customer has high wear numbers, they'll recommend not extending
the OCI, but they'll never recommend a change in viscosity; why is that?

 

[Burt]

I agree that in general, changing the interval in response to wear numbers makes no senses at all. The rate of wear will continue regardless of incremental adjustments in OCI. They should focus on viscosity, TBN, boron and other factors that show the oil life is used up.

 

[Jim Allen]

In no particular order:

1) You are misrepresenting a situation to suit your assertion that thicker is always better. Plus, you have seen only a tiny, miniscule fraction of the UOA Blackstone has produced, so using the term "ever" is wild speculation at best.

2) Because seldom does initial viscosity (when properly determined and correct for the situation) have an appreciable effect on wear metals. When it does, it's due a specific situation like high heat, high stress, excessive fuel dilution or rapid shear (to name a few).

3) The OCI does change the rate of wear in that wear increases as the oil breaks down and as contaminants build up in the oil. But, yes, the OCI is largely a response to the rate of wear more than anything. When the level of contaminants reaches a specific level (which is variable), the oil needs to come out. Sometimes an oil is sheared or diluted to a lower than safe viscosity and that might be an indicator for a more frequent OCI. If you look at UOAs, however, you don't often see problems with more wear from oil that that shear down... such as the common case of a 5W30 grade that shears down into the upper 20 grade.

4) Chasing minor fluctuations in wear metals is a fool's game in and of itself. The only way to make wear analysis more accurate is by using strict scientific procedures, frequent and regular testing.

5) In a similar vein, taking the UOA's seen here to draw any broad conclusions from wear metals that thicker is better is also a major error. Most of what you see here are "one shots" and "snapshots" that are only useful for interpreting oil condition, not engine condition. Too many variables exist in the vast majority of UOAs presented here for many useful broad conclusions.

 

[INDYMAC]

Originally Posted By: Jim Allen
In no particular order:

1) You are misrepresenting a situation to suit your assertion that thicker is always better. Plus, you have seen only a tiny, miniscule fraction of the UOA Blackstone has produced, so using the term "ever" is wild speculation at best.

2) Because seldom does initial viscosity (when properly determined and correct for the situation) have an appreciable effect on wear metals. When it does, it's due a specific situation like high heat, high stress, excessive fuel dilution or rapid shear (to name a few).

3) The OCI does change the rate of wear in that wear increases as the oil breaks down and as contaminants build up in the oil. But, yes, the OCI is largely a response to the rate of wear more than anything. When the level of contaminants reaches a specific level (which is variable), the oil needs to come out. Sometimes an oil is sheared or diluted to a lower than safe viscosity and that might be an indicator for a more frequent OCI. If you look at UOAs, however, you don't often see problems with more wear from oil that that shear down... such as the common case of a 5W30 grade that shears down into the upper 20 grade.

4) Chasing minor fluctuations in wear metals is a fool's game in and of itself. The only way to make wear analysis more accurate is by using strict scientific procedures, frequent and regular testing.

5) In a similar vein, taking the UOA's seen here to draw any broad conclusions from wear metals that thicker is better is also a major error. Most of what you see here are "one shots" and "snapshots" that are only useful for interpreting oil condition, not engine condition. Too many variables exist in the vast majority of UOAs presented here for many useful broad conclusions.


These are all good reasons that Jim provides, but I'll take it one step further. None of the comments you see on Blackstone reports are provided by a qualified tribologist. So any comments/recommendations made by Blackstone could result in a liable situation. I think these technicians are out of their league when it comes to tribology.

 

[Merkava_4]

Originally Posted By: Jim Allen

1) You are misrepresenting a situation to suit your assertion that thicker is always better. Plus, you have seen only a tiny, miniscule fraction of the UOA Blackstone has produced, so using the term "ever" is wild speculation at best.


I'll respond to that first statement because it appears to be directed towards me personally:

I do not believe that thicker is always better. When I see high wear metals and the oil being tested is 5W-20 or 5W-30, and the silicon ingestion is low, my immediate assumption is that the viscosity is wrong for that engine. What do I base that assumption on? I base that assumption on the single most important factor impacting on how an oil interacts with an engine; its viscosity. If I'm wrong in making that assumption, then you need to tell me. We're all here to learn the correct way; you may as well start with me.

 

[Garak]

Originally Posted By: Merkava_4
I do not believe that thicker is always better. When I see high wear metals and the oil being tested is 5W-20 or 5W-30, and the silicon ingestion is low, my immediate assumption is that the viscosity is wrong for that engine. What do I base that assumption on? I base that assumption on the single most important factor impacting on how an oil interacts with an engine; its viscosity.


The first problem is equating figures from a simple UOA with "wear metals." All kinds of things can alter these numbers, including viscosity, OCI, oil choice, driving style, and so forth. The numbers on a UOA are certainly not wear numbers. I see all kinds of voodoo with people trying to read "wear numbers" like tea leaves - it's just as scientific, anyhow.

When looking at a UOA, what I tend to check first are TBN and viscosity. Personally, I don't like a lot of oil shear, but some engines do it. Jumping to a heavier grade doesn't eliminate that, nor does it take into account that the manufacture may have already factored it in.

If I were to see shearing or fuel dilution (that wasn't the result of some fuel delivery issue), I'd be looking to reduce OCI rather than go to a heavier oil. In a lot of ways, I'm a thick oil guy - that is, if it's appropriate and specified for the vehicle.

Never once in all my years and millions of miles of fleet usage did I ever use a heavier oil than specified. I haven't run a taxi on anything heavier than an energy conserving 30 weight for over thirty years. I've only used 40 weights in vehicles for which it was specified, and even then, only if it was the preferred grade, or to slow leakage, and even then, only if it was acceptable according to the specification, even long out of warranty. With the shift to 20 weights, things have gone just as well.

I could probably count on one hand all the engine lines I've seen where the manufacturer is (or was) specifying too light an oil. In those cases, you'll see the manufacturer getting nailed with warranty claims.

Blackstone, at least, seems to concentrate on adjusting OCIs. That is, after all, the primary reason people get UOAs done. They're not looking for a second opinion on oil viscosity.

 

[cchase]

Originally Posted By: Merkava_4

I do not believe that thicker is always better. When I see high wear metals and the oil being tested is 5W-20 or 5W-30, and the silicon ingestion is low, my immediate assumption is that the viscosity is wrong for that engine. What do I base that assumption on? I base that assumption on the single most important factor impacting on how an oil interacts with an engine; its viscosity. If I'm wrong in making that assumption, then you need to tell me. We're all here to learn the correct way; you may as well start with me.

The problem is your assumption that high wear metals and low silicon automatically mean that the oil is too thin.

 

[Jim Allen]

Originally Posted By: Merkava_4
Originally Posted By: Jim Allen

1) You are misrepresenting a situation to suit your assertion that thicker is always better. Plus, you have seen only a tiny, miniscule fraction of the UOA Blackstone has produced, so using the term "ever" is wild speculation at best.


I'll respond to that first statement because it appears to be directed towards me personally:

I do not believe that thicker is always better. When I see high wear metals and the oil being tested is 5W-20 or 5W-30, and the silicon ingestion is low, my immediate assumption is that the viscosity is wrong for that engine. What do I base that assumption on? I base that assumption on the single most important factor impacting on how an oil interacts with an engine; its viscosity. If I'm wrong in making that assumption, then you need to tell me. We're all here to learn the correct way; you may as well start with me.

Well, Garak said most of what I would have said, RE interpreting the contaminants in the snapshot UOAs seen here as any indicator that a thicker oil is needed. To prove that it does, you'd need dozens of samples taken on the thinner oil and then dozens more on the thicker oil, the UOAs from each oil taken in with the engines undergoing roughly the same conditions, and with identical additive packages, to prove that the heavier oil produces lower metals, due to the viscosity difference alone. It's proven that in some conditions, usually harsh and hot operating conditions, an engine can benefit from a thicker oil but usually that is covered in the OEM manual specific to that engine.

I'm glad to hear you say you don't think thicker oil is always better. Many of your previous posts and responses left me with that impression and I'm glad to hear I was wrong.

But, no, I don't think viscosity is the single most important factor. Try whichever viscosity oil you like without additives and see how long the engine lasts. Additives will make or break any oil and you could call them an equalizer at any grade. And without the correct viscosity, the best additive package in the world is no good. It's all about synergy, all the parts working towards a better whole. I think it's a mistake to focus on only one aspect of the whole. That said, if you look at some of the work Lubrizol is doing on low viscosity gear oils < www.axlefacts.com>, you can see that additives are beginning to go past that 50/50 mark in terms of importance.

 

[qr25de]

Originally Posted By: Jim Allen
In no particular order:

1) You are misrepresenting a situation to suit your assertion that thicker is always better. Plus, you have seen only a tiny, miniscule fraction of the UOA Blackstone has produced, so using the term "ever" is wild speculation at best.

2) Because seldom does initial viscosity (when properly determined and correct for the situation) have an appreciable effect on wear metals. When it does, it's due a specific situation like high heat, high stress, excessive fuel dilution or rapid shear (to name a few).

3) The OCI does change the rate of wear in that wear increases as the oil breaks down and as contaminants build up in the oil. But, yes, the OCI is largely a response to the rate of wear more than anything. When the level of contaminants reaches a specific level (which is variable), the oil needs to come out. Sometimes an oil is sheared or diluted to a lower than safe viscosity and that might be an indicator for a more frequent OCI. If you look at UOAs, however, you don't often see problems with more wear from oil that that shear down... such as the common case of a 5W30 grade that shears down into the upper 20 grade.

4) Chasing minor fluctuations in wear metals is a fool's game in and of itself. The only way to make wear analysis more accurate is by using strict scientific procedures, frequent and regular testing.

5) In a similar vein, taking the UOA's seen here to draw any broad conclusions from wear metals that thicker is better is also a major error. Most of what you see here are "one shots" and "snapshots" that are only useful for interpreting oil condition, not engine condition. Too many variables exist in the vast majority of UOAs presented here for many useful broad conclusions.


6) This is all ignoring the fact that in a lot of cases, as mileage increases, filtration improves and the wear rate decreases after the initial oil change.

 

[ltslimjim]

Originally Posted By: Jim Allen

5) In a similar vein, taking the UOA's seen here to draw any broad conclusions from wear metals that thicker is better is also a major error. Most of what you see here are "one shots" and "snapshots" that are only useful for interpreting oil condition, not engine condition. Too many variables exist in the vast majority of UOAs presented here for many useful broad conclusions.


This says it all, good way of conveying the reality of the UOAs we see here.

 

[OVERKILL]

Originally Posted By: Jim Allen
In no particular order:

1) You are misrepresenting a situation to suit your assertion that thicker is always better. Plus, you have seen only a tiny, miniscule fraction of the UOA Blackstone has produced, so using the term "ever" is wild speculation at best.

2) Because seldom does initial viscosity (when properly determined and correct for the situation) have an appreciable effect on wear metals. When it does, it's due a specific situation like high heat, high stress, excessive fuel dilution or rapid shear (to name a few).

3) The OCI does change the rate of wear in that wear increases as the oil breaks down and as contaminants build up in the oil. But, yes, the OCI is largely a response to the rate of wear more than anything. When the level of contaminants reaches a specific level (which is variable), the oil needs to come out. Sometimes an oil is sheared or diluted to a lower than safe viscosity and that might be an indicator for a more frequent OCI. If you look at UOAs, however, you don't often see problems with more wear from oil that that shear down... such as the common case of a 5W30 grade that shears down into the upper 20 grade.

4) Chasing minor fluctuations in wear metals is a fool's game in and of itself. The only way to make wear analysis more accurate is by using strict scientific procedures, frequent and regular testing.

5) In a similar vein, taking the UOA's seen here to draw any broad conclusions from wear metals that thicker is better is also a major error. Most of what you see here are "one shots" and "snapshots" that are only useful for interpreting oil condition, not engine condition. Too many variables exist in the vast majority of UOAs presented here for many useful broad conclusions.


Excellent summation sir!

 

[Quattro Pete]

Originally Posted By: Merkava_4
When I see high wear metals and the oil being tested is 5W-20 or 5W-30, and the silicon ingestion is low, my immediate assumption is that the viscosity is wrong for that engine. What do I base that assumption on? I base that assumption on the single most important factor impacting on how an oil interacts with an engine; its viscosity. If I'm wrong in making that assumption, then you need to tell me. We're all here to learn the correct way; you may as well start with me.

An engine may have a problem that's not related to the oil itself, so how can you attribute metal wear to the oil?

Secondly, most of the wear occurs at cold startup, so most of us should be using thinner oils, not thicker. At cold startup, the oil is too thick to quickly begin circulating and providing protection.

Finally, as has been said here many times before, a $20 Blackstone UOA is not a proper tool to assess engine wear related to oil choice/performance. Blackstone knows this, and hence they don't typically make any oil choice recommendations. It is only a useful tool to detect things like fuel/coolant contamination and to determine if the oil is suitable for continued use based on its TBN/TAN. Trending has some value too as you can detect spikes of various elements.

 

[Merkava_4]

Burt
Jim Allen
INDYMAC
Garak
cchase
qe25de
Itslimjim
OVERK1LL
Quattro Pete


Gentlemen,

Thank you all very much for your educational posts. There's a lot of high quality information in this thread and I've learned a lot. Hopefully, other people viewing this thread will find it as educational as I have. Thanks again.

 

[Garak]

No problem. Trust me, I completely understand your skepticism with respect to thinner oils. I've always had that nagging thought that whatever grade specified might be too thin, the Germans must know what they're doing with heavy oils, that CAFE drives everything, and so forth.

However, results trump skepticism. My dad, who I tended to consider an old farmer and a very old school mechanic, was far ahead of his time with respect to thin oils. He always, and I mean always, used the lightest grade specified in anything he operated. I remember once I almost got my backside tanned for putting straight 30 weight in some farm equipment, rather than an appropriate multigrade. Fortunately for me, I was able to show him that the manual authorized a straight 30 weight, among various other viscosities. The only thing he was pleased about was that I got rid of his old stash of straight 30 so he wouldn't have to look at it again.

 

[Jim Allen]

Happy to be of service. Most of us came to this board with misconceptions and certainties about "the way thing are." Many of us found those things dashed upon the rocks of knowledge by waves of fact. Sometimes that's a very bitter pill. How well an individual accepts the destruction of misconceptions is a sign of character and you've earned high marks.