Rubbish advice on BITOG these days...
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Originally Posted By: ZeeOSix
There's been many discussions about wear protection, and the consensus is that viscosity really doesn't factor in, it's the anti-wear additives that actually prevents wear, not the viscosity.
Where on earth did you get that ?
Rat's blog ?
There's been many discussions about wear protection, and the consensus is that viscosity really doesn't factor in, it's the anti-wear additives that actually prevents wear, not the viscosity.
Where on earth did you get that ?
Rat's blog ?
Originally Posted By: Shannow
Originally Posted By: ZeeOSix
There's been many discussions about wear protection, and the consensus is that viscosity really doesn't factor in, it's the anti-wear additives that actually prevents wear, not the viscosity.
Where on earth did you get that ?
Rat's blog ?
I'm sure if the viscosity was so low that the MOFT was significantly compromised as temperatures increased to cause metal-to-metal contact then wear would occur regardless of any AW components. If engine wear was a strong function of viscosity then all these cars (many with over 400 HP) using xW-20 weight oils should be in the junk yard by 100K miles, and should therefore be running xW-40 or xW-50 instead. Probably see even thinner than 20 weight oils before too long.
Just for you "Mr. SAE Paper".
Can't believe you haven't come across information like this before.
http://papers.sae.org/811224/
Originally Posted By: ZeeOSix
There's been many discussions about wear protection, and the consensus is that viscosity really doesn't factor in, it's the anti-wear additives that actually prevents wear, not the viscosity.
Where on earth did you get that ?
Rat's blog ?
I'm sure if the viscosity was so low that the MOFT was significantly compromised as temperatures increased to cause metal-to-metal contact then wear would occur regardless of any AW components. If engine wear was a strong function of viscosity then all these cars (many with over 400 HP) using xW-20 weight oils should be in the junk yard by 100K miles, and should therefore be running xW-40 or xW-50 instead. Probably see even thinner than 20 weight oils before too long.
Just for you "Mr. SAE Paper".
http://papers.sae.org/811224/
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
Last edited:
Originally Posted By: Jetronic
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
The abstract gives the bottom line that the chemical composition was the dominate factor in wear protection. Those baseline demerits shown in Table 1 were established before the additive "Performance Package" defined in Table 2 was added. So the additive package is giving most of the wear protection regardless of viscosity as the paper eludes to in the abstract. With modern oils I'd think it's probably even more so then back when this testing was done.
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
The abstract gives the bottom line that the chemical composition was the dominate factor in wear protection. Those baseline demerits shown in Table 1 were established before the additive "Performance Package" defined in Table 2 was added. So the additive package is giving most of the wear protection regardless of viscosity as the paper eludes to in the abstract. With modern oils I'd think it's probably even more so then back when this testing was done.
Originally Posted By: ZeeOSix
Originally Posted By: Shannow
Holy Cognitive Bias secret agent man...
LoL ... you mean "cherry picking" like you're an expert at doing?
For the audience...
http://www.sae.org/search/?qt=viscosity+bearing+wear&sort=relevance&sort-dir=desc&display=list&content-type=%28%22PAPER%22%29
Narrowed down to papers since 2010
http://www.sae.org/search/?qt=viscosity+bearing+wear&sort=relevance&sort-dir=desc&display=list&content-type=%28%22PAPER%22%29&sdate=2010&edate=2017
Originally Posted By: Shannow
Holy Cognitive Bias secret agent man...
LoL ... you mean "cherry picking" like you're an expert at doing?
For the audience...
http://www.sae.org/search/?qt=viscosity+bearing+wear&sort=relevance&sort-dir=desc&display=list&content-type=%28%22PAPER%22%29
Narrowed down to papers since 2010
http://www.sae.org/search/?qt=viscosity+bearing+wear&sort=relevance&sort-dir=desc&display=list&content-type=%28%22PAPER%22%29&sdate=2010&edate=2017
To clarify my viewpoint, with the advent of ever improved AW add packages the viscosity is becoming less and less of a factor in wear protection (as the SAE paper concludes). Take all the AW add package away and of course the viscosity is the only thing left and then becomes the main factor. As oil has evolved over time in order to provide adequate wear protection in the modern engines of today, it's mainly the add package doing the protection. Seems engine manufactures are almost all specifying xW-20 oils and they are fast becoming the norm with new cars.
Of course if you keep reducing the viscosity, at some point no matter what the AW package is the wear protection is going to suffer. That's what some of the SAE papers also address. Maybe better wear packages in the future will allow even thinner oils than what we see today.
Of course if you keep reducing the viscosity, at some point no matter what the AW package is the wear protection is going to suffer. That's what some of the SAE papers also address. Maybe better wear packages in the future will allow even thinner oils than what we see today.
Ohh, edits again...
anyway
https://bobistheoilguy.com/forums/ubbthreads.php/topics/3390995/Why_designers_allow_mixed_lubr
anyway
https://bobistheoilguy.com/forums/ubbthreads.php/topics/3390995/Why_designers_allow_mixed_lubr
Originally Posted By: ZeeOSix
Of course if you keep reducing the viscosity, at some point no matter what the AW package is the wear protection is going to suffer. That's what some of the SAE papers also address. Maybe better wear packages in the future will allow even thinner oils than what we see today.
To show an example, from: http://papers.sae.org/2013-01-0331/
Graph showing wear vs viscosity for various engine components. All but the con-rod bearings didn't show much if any change in the wear rate as long as the viscosity was above 2.2 cP. I also saw that mentioned in a few other papers discussing wear vs viscosity.
Of course if you keep reducing the viscosity, at some point no matter what the AW package is the wear protection is going to suffer. That's what some of the SAE papers also address. Maybe better wear packages in the future will allow even thinner oils than what we see today.
To show an example, from: http://papers.sae.org/2013-01-0331/
Graph showing wear vs viscosity for various engine components. All but the con-rod bearings didn't show much if any change in the wear rate as long as the viscosity was above 2.2 cP. I also saw that mentioned in a few other papers discussing wear vs viscosity.
Originally Posted By: ZeeOSix
Originally Posted By: ZeeOSix
Of course if you keep reducing the viscosity, at some point no matter what the AW package is the wear protection is going to suffer. That's what some of the SAE papers also address. Maybe better wear packages in the future will allow even thinner oils than what we see today.
To show an example, from: http://papers.sae.org/2013-01-0331/
Graph showing wear vs viscosity for various engine components. All but the con-rod bearings didn't show much if any change in the wear rate as long as the viscosity was above 2.2 cP. I also saw that mentioned in a few other papers discussing wear vs viscosity.
FYI, on a big diesel engine, the "connecting rod bush" is the bush at the little end of the conrod...it's not hydrodynamic by nature, as it's clearly 15-25 degrees this way, and 15-25 degrees that way each revolution...the paper even EXPLAINS that the bush is the con-rod small end.
Ummm....next...
Originally Posted By: ZeeOSix
Of course if you keep reducing the viscosity, at some point no matter what the AW package is the wear protection is going to suffer. That's what some of the SAE papers also address. Maybe better wear packages in the future will allow even thinner oils than what we see today.
To show an example, from: http://papers.sae.org/2013-01-0331/
Graph showing wear vs viscosity for various engine components. All but the con-rod bearings didn't show much if any change in the wear rate as long as the viscosity was above 2.2 cP. I also saw that mentioned in a few other papers discussing wear vs viscosity.
FYI, on a big diesel engine, the "connecting rod bush" is the bush at the little end of the conrod...it's not hydrodynamic by nature, as it's clearly 15-25 degrees this way, and 15-25 degrees that way each revolution...the paper even EXPLAINS that the bush is the con-rod small end.
Ummm....next...
Originally Posted By: ZeeOSix
Originally Posted By: Jetronic
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
The abstract gives the bottom line that the chemical composition was the dominate factor in wear protection. Those baseline demerits shown in Table 1 were established before the additive "Performance Package" defined in Table 2 was added. So the additive package is giving most of the wear protection regardless of viscosity as the paper eludes to in the abstract. With modern oils I'd think it's probably even more so then back when this testing was done.
No, the paragraph titled engine Test Program - Procedure 1 clearly states they all received the performance package prior to testing.
Originally Posted By: Jetronic
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
The abstract gives the bottom line that the chemical composition was the dominate factor in wear protection. Those baseline demerits shown in Table 1 were established before the additive "Performance Package" defined in Table 2 was added. So the additive package is giving most of the wear protection regardless of viscosity as the paper eludes to in the abstract. With modern oils I'd think it's probably even more so then back when this testing was done.
No, the paragraph titled engine Test Program - Procedure 1 clearly states they all received the performance package prior to testing.
Originally Posted By: Jetronic
Originally Posted By: ZeeOSix
Originally Posted By: Jetronic
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
The abstract gives the bottom line that the chemical composition was the dominate factor in wear protection. Those baseline demerits shown in Table 1 were established before the additive "Performance Package" defined in Table 2 was added. So the additive package is giving most of the wear protection regardless of viscosity as the paper eludes to in the abstract. With modern oils I'd think it's probably even more so then back when this testing was done.
No, the paragraph titled engine Test Program - Procedure 1 clearly states they all received the performance package prior to testing.
If that's the case, then explain why they made the conclusive statements in the abstract that the chemical composition, not the viscosity, was the dominate factor in wear protection. Since we can't see the whole paper, there must be something else going on to explain why they concluded what they did in the abstract.
Originally Posted By: ZeeOSix
Originally Posted By: Jetronic
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
The abstract gives the bottom line that the chemical composition was the dominate factor in wear protection. Those baseline demerits shown in Table 1 were established before the additive "Performance Package" defined in Table 2 was added. So the additive package is giving most of the wear protection regardless of viscosity as the paper eludes to in the abstract. With modern oils I'd think it's probably even more so then back when this testing was done.
No, the paragraph titled engine Test Program - Procedure 1 clearly states they all received the performance package prior to testing.
If that's the case, then explain why they made the conclusive statements in the abstract that the chemical composition, not the viscosity, was the dominate factor in wear protection. Since we can't see the whole paper, there must be something else going on to explain why they concluded what they did in the abstract.
They were talking about corrosive and abrasive wear after the abstract, where HTHS plays a minor role but chemical composition is key. Top of page 4.
Originally Posted By: ZeeOSix
Originally Posted By: Jetronic
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
The abstract gives the bottom line that the chemical composition was the dominate factor in wear protection. Those baseline demerits shown in Table 1 were established before the additive "Performance Package" defined in Table 2 was added. So the additive package is giving most of the wear protection regardless of viscosity as the paper eludes to in the abstract. With modern oils I'd think it's probably even more so then back when this testing was done.
I don't really like attempting to discuss papers that I don't have access to, but, for what its worth, and from what you present, that 1981 paper's conclusions do seem to support your contention.
However, the preamble above refers to a dichotomy, and cites a body of literature supporting the opposite contention.
A dichotomy implies two sides, and you are selectively quoting one of them.
I'd also think that, if you can reduce the protection provided by an SAE 30 oil to below that of a SAE 5 by elimination of the additive package, that implies that the additive package is very important, but it also seems to imply that, for equivalent, intact additive packages, the SAE 30 oil still provided superior protection to the SAE 5.
Originally Posted By: Jetronic
1981... HTHS requirements have been added to the SAE viscosity classification since then, and been made stricter recently.
and on the bottom o the last page in the preview, they list demerits for 3 oil viscosties: the 5w-20 scored 3 times worse than the other 2...
The abstract gives the bottom line that the chemical composition was the dominate factor in wear protection. Those baseline demerits shown in Table 1 were established before the additive "Performance Package" defined in Table 2 was added. So the additive package is giving most of the wear protection regardless of viscosity as the paper eludes to in the abstract. With modern oils I'd think it's probably even more so then back when this testing was done.
I don't really like attempting to discuss papers that I don't have access to, but, for what its worth, and from what you present, that 1981 paper's conclusions do seem to support your contention.
However, the preamble above refers to a dichotomy, and cites a body of literature supporting the opposite contention.
A dichotomy implies two sides, and you are selectively quoting one of them.
I'd also think that, if you can reduce the protection provided by an SAE 30 oil to below that of a SAE 5 by elimination of the additive package, that implies that the additive package is very important, but it also seems to imply that, for equivalent, intact additive packages, the SAE 30 oil still provided superior protection to the SAE 5.
Originally Posted By: Jetronic
They were talking about corrosive and abrasive wear after the abstract, where HTHS plays a minor role but chemical composition is key. Top of page 4.
Are you talking about this statement on top of page 4? That statement has nothing to do with the testing they did. They were not testing wear as a function of corrosion or abrasion of used motor oils used in extended drains. Read the abstract I highlighted earlier, it says absolutely nothing about corrosive or abrasive wear, only the relationship between wear and viscosity.
Also, explain this graph from the more timely paper that shows wear essentially is constant if the viscosity is above 2.2 cP.
And along side that here's another SAE paper abstract that pretty much supports the same conclusion.
They were talking about corrosive and abrasive wear after the abstract, where HTHS plays a minor role but chemical composition is key. Top of page 4.
Are you talking about this statement on top of page 4? That statement has nothing to do with the testing they did. They were not testing wear as a function of corrosion or abrasion of used motor oils used in extended drains. Read the abstract I highlighted earlier, it says absolutely nothing about corrosive or abrasive wear, only the relationship between wear and viscosity.
Also, explain this graph from the more timely paper that shows wear essentially is constant if the viscosity is above 2.2 cP.
And along side that here's another SAE paper abstract that pretty much supports the same conclusion.
Originally Posted By: ZeeOSix
Also, explain this graph from the more timely paper that shows wear essentially is constant if the viscosity is above 2.2 cP.
And along side that here's another SAE paper abstract that pretty much supports the same conclusion.
Easily explained with some of the basics that they would have taught you at secrete agent school. Remember back to the Stribeck curve.
You have cherry picked articles that are focused on the boundary/mixed end, where minimum oil film thickness has been obtained, and asperite contact is commencing.
As you well know, in that range, life is generated by surface chemical and (and dry film in some cases) interactions, not by hydrodynamics.
So if you pick an area that's boundary/mixed lubrication, then it's no surprise whatsoever that viscosity doesn't play a part.
The small end bush (LOL, conrod bearing) doesn't rotate, it has a relatively small arc of movement, is not hydrodynamic, and therefore is additive dependent not viscosity dependent. Camshaft same, it's boundary.
Piston rings (as I tried to explain in the Rat thread to no avail) have multiple components...at points they are stopped, and at others full hydrodynamic.
There you go...explained.
Other areas of the engine are hydrodynamic, like bearings and piston skirts...viscosity keeps them apart, and they are relatively soft.
Per my link to the boundary/mixed discussion, and seminars that Solarent has brought up, they are changing bearing materials, mechanical designs, and the additive packs needed to increase the boundary/mixed contact in these regions too, and get the next 0.5% fuel economy out of them.
Re Stribeck curve and engine components
Note per below the actions of friction modifiers and AW additives on the region in the left (where viscosity is no longer a significant part of the mix)..."Wear controlled by AW and EP additives"
Also, explain this graph from the more timely paper that shows wear essentially is constant if the viscosity is above 2.2 cP.
And along side that here's another SAE paper abstract that pretty much supports the same conclusion.
Easily explained with some of the basics that they would have taught you at secrete agent school. Remember back to the Stribeck curve.
You have cherry picked articles that are focused on the boundary/mixed end, where minimum oil film thickness has been obtained, and asperite contact is commencing.
As you well know, in that range, life is generated by surface chemical and (and dry film in some cases) interactions, not by hydrodynamics.
So if you pick an area that's boundary/mixed lubrication, then it's no surprise whatsoever that viscosity doesn't play a part.
The small end bush (LOL, conrod bearing) doesn't rotate, it has a relatively small arc of movement, is not hydrodynamic, and therefore is additive dependent not viscosity dependent. Camshaft same, it's boundary.
Piston rings (as I tried to explain in the Rat thread to no avail) have multiple components...at points they are stopped, and at others full hydrodynamic.
There you go...explained.
Other areas of the engine are hydrodynamic, like bearings and piston skirts...viscosity keeps them apart, and they are relatively soft.
Per my link to the boundary/mixed discussion, and seminars that Solarent has brought up, they are changing bearing materials, mechanical designs, and the additive packs needed to increase the boundary/mixed contact in these regions too, and get the next 0.5% fuel economy out of them.
Re Stribeck curve and engine components
Note per below the actions of friction modifiers and AW additives on the region in the left (where viscosity is no longer a significant part of the mix)..."Wear controlled by AW and EP additives"
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