Big words. I'm not a chemist or tribologist, just a mechanic. Always reading, trying to learn. I came across these words, "...pressure - viscosity coefficient. The measure for a lubricants EHL film formation capability." When i see the word pressure, i think of racing. I'm wondering if this "measure" or spec is something worth looking at when choosing an oil for racing applications? Is it even a spec on an an oil data sheet?
Pressure -Viscosity Coefficient
- Thread starter Fishbowl
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A few weeks ago I saw those same words, "pressure viscosity coefficient". Googled a little and to my suprise found out that viscosity Increases with increased pressure. As a consumer it was news to me.
I have used this term on here about 30 times here on the car and truck oil section. And it was kind of funny becasue it could not have been more clear that all the psuedo-experts preachers here in lubrication had never heard of it before. The density of lubricants goes up with pressure and in highly loaded bearings (high loads on a ball bearing), the lubricant can essentially become a plastic solid while in the load zone. If the density goes up, it can be intuitive that it's harder to shear the lubricant and the force needed to shear the lubricant (at a given rate)is essentially the viscosity.
Also, FYI, PAO sythetic basetocks have poor pressure-viscosity characteristics.
1911
Hello Utah John Browning,
One thing to bear in mind is that communism and disinformation go hand in hand. I will not review past posts on the alpha coefficient because I fear exposure to disinformation...In fact I can smell it.
I am not full of myself, I am full of 8 rounds of .45ACP. I am simply a recoil operated tautology. You'll have to live with your invention..the poorly designed extractor without a spring........and the barrel link which nobody copied John?
And JB, one more thing, have you cleaned and lubed you 1911 today?
1911......the old .45 ACP solution to the new 9mm problem.
1911 it has been discussed in length a number of times by a number of people. In most cases the terminology used is not the correct tribological terminology. Molakule,Terry,G-Man II,TooSlick have used the terminology "pressure - viscosity coefficient". You have only read a very little bit of what has been discussed here in the past. A lot has changed since this sites inception.
Many of us also go to Noria wich is much more technical. Noria has more tribologists and less regualar guys on the site. The idea or principal is all that is important the words used to describe the princapal have very little meaning on their own.
Most of us are not engineer, triboligists or tech.'s! I am a Tech and aproach oil from a stand point of observation of results and failures. I could care less in the end what the white paper's say. The engine will tell it's tale and can be easily observed both directly and indirectly with observation,tear down and UOA.
I am glad this site is not your site as the membership would be very small. If you have all the answere why even bother with this site or the vast majority of it's members?
Quote "I have used this term on here about 30 times here on the car and truck oil section. And it was kind of funny becasue it could not have been more clear that all the psuedo-experts preachers here in lubrication had never heard of it before. The density of lubricants goes up with pressure and in highly loaded bearings "
Even I have mentioned this very thing a number of times. I have mentioned this effect when talking about newtonian fluids! You might want to read the last 4 years worth of post's before you get so full of yourself.
Many of us also go to Noria wich is much more technical. Noria has more tribologists and less regualar guys on the site. The idea or principal is all that is important the words used to describe the princapal have very little meaning on their own.
Most of us are not engineer, triboligists or tech.'s! I am a Tech and aproach oil from a stand point of observation of results and failures. I could care less in the end what the white paper's say. The engine will tell it's tale and can be easily observed both directly and indirectly with observation,tear down and UOA.
I am glad this site is not your site as the membership would be very small. If you have all the answere why even bother with this site or the vast majority of it's members?
Quote "I have used this term on here about 30 times here on the car and truck oil section. And it was kind of funny becasue it could not have been more clear that all the psuedo-experts preachers here in lubrication had never heard of it before. The density of lubricants goes up with pressure and in highly loaded bearings "
Even I have mentioned this very thing a number of times. I have mentioned this effect when talking about newtonian fluids! You might want to read the last 4 years worth of post's before you get so full of yourself.
1911 - so with being a "protective factor" (yes?) in loaded equipment bearings - esspecially sleeve type bearings as found in automotive engine main and connecting rod locations, then the point you noted about PAO basestocks having poor pressure-viscosity characteristics puts it at a disadvantage.
After having read the third edition of "The Practical Handbook of Machinery Lubrication," the "superior" picture of synthetics seem to be deminishing - becoming more of a "same, but different" sort of thing.
- pour point is one thing, but for all intensive purposes, cranking and pumping viscosities is what is really needed to be focused upon.
- as far as dino pour points, the pour point depressents used may with moderate fulctuations around the pour point, cause a deminishing in pour point dispersent effect - that is the pour point for the lubricant will rise somewhat. In the reading it was noted that this effect could be reversed by returning the lubricant to room temperature. I would think that bring the oil up to running temperature would also have the same curing effect.
If the bulk oil was to be brough up to temp on a daily bases, I would think there as being little to be concerned about with the pour point loss effect.
PAO's and the like don't suffer from this aspect being that they contain no waxes, but I ponder as to the fact that their viscosities are brought about by mixing of two or more different viscosity oils verses taking a light weight oil in the case of a dino and then adding VII's...may leave a synthetic with a higher viscosity while it's increasing temperature to operating conditions. How might this compare to the viscosity effect by VII on a dino, and how much does the VI really play out as far as accuracy in determining like comparison between synthetics and dinos???
Sorry for any confusion, but my nephew becons my attention.
After having read the third edition of "The Practical Handbook of Machinery Lubrication," the "superior" picture of synthetics seem to be deminishing - becoming more of a "same, but different" sort of thing.
- pour point is one thing, but for all intensive purposes, cranking and pumping viscosities is what is really needed to be focused upon.
- as far as dino pour points, the pour point depressents used may with moderate fulctuations around the pour point, cause a deminishing in pour point dispersent effect - that is the pour point for the lubricant will rise somewhat. In the reading it was noted that this effect could be reversed by returning the lubricant to room temperature. I would think that bring the oil up to running temperature would also have the same curing effect.
If the bulk oil was to be brough up to temp on a daily bases, I would think there as being little to be concerned about with the pour point loss effect.
PAO's and the like don't suffer from this aspect being that they contain no waxes, but I ponder as to the fact that their viscosities are brought about by mixing of two or more different viscosity oils verses taking a light weight oil in the case of a dino and then adding VII's...may leave a synthetic with a higher viscosity while it's increasing temperature to operating conditions. How might this compare to the viscosity effect by VII on a dino, and how much does the VI really play out as far as accuracy in determining like comparison between synthetics and dinos???
Sorry for any confusion, but my nephew becons my attention.
So the less pressure viscosity coefficient knowlege a person has, the more chance of being a communist??
MolaKule
Staff member
Here is an excellent explantion of viscosity and
the "viscosity-pressure" situation.
http://www.herguth.com/technical/PHYSICAL.HTM
Thanks, but I'll take my .357 S&W 586 large frame and rifled "anticommunist/anti-socialist" 12 Ga. slug gun anytime.
the "viscosity-pressure" situation.
http://www.herguth.com/technical/PHYSICAL.HTM
Thanks, but I'll take my .357 S&W 586 large frame and rifled "anticommunist/anti-socialist" 12 Ga. slug gun anytime.
Molakule, you are "Americana" even if you don't own a 1911. I've always known it and I've never suspected otherwise..........but wouldn't it be nice to add a classic 1911 to your collection?
1911.....a .45 ACP rebuttal to the communist insurgency in the Peoples Republic of Kalifornia
MolaKule
Staff member
Yes it would. I have looked seriously at the Kimber, with the .22 LR conversion kits.
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