Slipperiness Quality of a Motor oil

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Yes, you read the title correctly.

Can someone explain what is the property of "slipperiness" as related to a PCMO oil and please direct me to the product data sheet number or ASTM test that measures this property/quality?
 
Ask Merkava 4. He likes to use that word.
smile.gif

I almost brought it up this morning in that thread that he used the term but I figured it not worth it.
 
I would guess it has someting to do with the amount of friction modifier added. Since friction modification can occur thorough use of moly or an ester base oil (and probably a plethora of other factors), it is not going to be easy to quantify IMO.
 
Bingo, JAG! It's best just to let the gibberish in that thread die...

But seriously, while the term "Slipperiness" does not even appear in the Noria resources library, I think we all realize it has something to do with the frictional properties of an oil and the friction modifier additives.

Or to be more correct, the co-efficient of friction for the oil.

What's the answer, when someone ask's, "What oils have the lowest co-efficients of friction & what test determines this?
 
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I would guess it has someting to do with the amount of friction modifier added. Since friction modification can occur thorough use of moly or an ester base oil (and probably a plethora of other factors), it is not going to be easy to quantify IMO.



From what I understand, friction reducers are the key to reduction of friction in modern motor oils - considerably more so than the base oils chosen.
 
We can certainly come up with what it might mean (like coefficient of friction) but I think the point is made-up words for physical properties should not be used in technical discussions.

Given that there are many states of lubrication, which are discussed here: http://www.bobistheoilguy.com/states of lubrication.html, and that the amount of total friction (fluid + possible metal to metal) will vary depending on the state, this concept cannot be simplified in a way that does not reference what state(s) are being discussed.

I think it is well established in engineering books that the lowest total friction occurs approximately when the film thickness is just thick enough to prevent metal to metal contact. That's just for ONE lubricated assembly (bearing, etc). An engine has so many different parts (and operating conditions) with different ideals as far as viscosity and additives are concerned that the oil for least total power loss due to friction is a compromise for all the different parts. It is most likely that in an engine you could keep trying thinner and thinner oils to the point that total friction would keep decreasing while excess wear on SOME parts keeps increasing. That's the compromise some race engine engineers have to make.

Ok, with all that said. I think a good, technically legit phrase that can replace "slipperiness" is total friction, which is the sum of fluid friction and metal to metal friction. All who agree, say yay?
smile.gif

If we all get savvy with the different states of lubrication and how often the different parts of engines spend time in each of those states, we will be on our way to being uber engine lubrication geeks.
 
Quote:


Ask Merkava 4. He likes to use that word.
smile.gif

I almost brought it up this morning in that thread that he used the term but I figured it not worth it.




Hey believe it or not, my spell check actually approves that word, but you got to use an 'I' instead of the 'Y'.
wink.gif
 
I thought slippery was basically a low(er) cSt @ 100 but a higher HT/HS. Wouldn't that naturally logically define a slippery oil because on the one hand you are thinner(less friction then a thicker oil) but you still protect because of the high(er) HT/HS?

or can you have a high cSt @ 100 *and* a high HT/HS??
 
Quote:


We can certainly come up with what it might mean (like coefficient of friction) but I think the point is made-up words for physical properties should not be used in technical discussions.

Given that there are many states of lubrication, which are discussed here: http://www.bobistheoilguy.com/states of lubrication.html, and that the amount of total friction (fluid + possible metal to metal) will vary depending on the state, this concept cannot be simplified in a way that does not reference what state(s) are being discussed.

I think it is well established in engineering books that the lowest total friction occurs approximately when the film thickness is just thick enough to prevent metal to metal contact. That's just for ONE lubricated assembly (bearing, etc). An engine has so many different parts (and operating conditions) with different ideals as far as viscosity and additives are concerned that the oil for least total power loss due to friction is a compromise for all the different parts. It is most likely that in an engine you could keep trying thinner and thinner oils to the point that total friction would keep decreasing while excess wear on SOME parts keeps increasing. That's the compromise some race engine engineers have to make.

Ok, with all that said. I think a good, technically legit phrase that can replace "slipperiness" is total friction, which is the sum of fluid friction and metal to metal friction. All who agree, say yay?
smile.gif

If we all get savvy with the different states of lubrication and how often the different parts of engines spend time in each of those states, we will be on our way to being uber engine lubrication geeks.




I think this is the reason why I want to stay with MC for my car right now. I am on 1st OCI with MC now and am coming up on an oil change in < 1000 miles. I feel that the oil is just like your defintion here about the film being "just thick enough" to not cause friction.. I would risk all that for an oil whose oil and friction modifiers may not be working in harmony as well perhaps even due to it being syn and using lesser base or no base stocks.

The final winner is the chemist whos genius makes "it all work" and "in its 'optimal' application" I am wondering how much efficient engine design plays a role in how well a particular oil works in an application. This could spawn the self made cliche of You don't pick the oil. Oil picks you.
 
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I thought slippery was basically a low(er) cSt @ 100 but a higher HT/HS. Wouldn't that naturally logically define a slippery oil because on the one hand you are thinner(less friction then a thicker oil) but you still protect because of the high(er) HT/HS?

or can you have a high cSt @ 100 *and* a high HT/HS??


I don't think a higher HTHS really has any correlation to "slipperiness." Thinner (to a point before metal to metal contact), more friction modifiers (to a point before overloading the oil with FM), higher group base oil--I think all these contribute to "slipperiness." There may be a trade off at the thinner end where you can gain some "slipperiness" by going a bit thinner than should be and compensate with a higher HTHS, but it probably is not a noticible difference and may counteract cancelling out any gain. Who knows? Why worry? The difference is infinitesimal!
 
Quote:


I thought slippery was basically a low(er) cSt @ 100 but a higher HT/HS. Wouldn't that naturally logically define a slippery oil because on the one hand you are thinner(less friction then a thicker oil) but you still protect because of the high(er) HT/HS?

or can you have a high cSt @ 100 *and* a high HT/HS??


What?
 
06VtecV6 - Since you clicked the reply button to my original post, I will reply back directly to you.

"Slippery" is not a defined technical term and does not belong in a technical discussion of motor oils. I'd suggest you refrain from using this term in all future posts.

I think everyone understands the nature of the term "slippery" - water on a tile floor makes it slippery for walking, ice forming on a road makes it slippery for driving.

And I think to be correct, the concept we are talking about is the co-efficient of friction for these surfaces/materials.

However, co-efficient of friction is not a part of the common data for an oil formulation & my guess is they all have such similar values that the number becomes meaningless.
 
What about automatic transmission fluids? They are designed with some offering more "bite" than others (think type F vs Dexron).

What happens to auto trannie base oil to make that happen?
 
Quote:


Yes, you read the title correctly.

Can someone explain what is the property of "slipperiness" as related to a PCMO oil and please direct me to the product data sheet number or ASTM test that measures this property/quality?




Would you like the results of that test to show the most slipperyness at cold start-up (or) normal engine operating temperature?
crazy.gif


My definition of cold-start slipperyness is something I have been doing for the past 30 years changing my own oil. Prior to pouring the new oil, I rub some (0W/5W/10W-30) on the tips of my forefinger and thumb. It's my own friction test - rubbing back & forth for around 10-15 seconds.

Which "COMMON-EVERYDAY FOUND" oils feel the slippery(est) between my fingers?
1) a)Pennzoil Platinum - b)Castrol GC 0W/30
2) a)Castrol Synthetic Blend - b)Motorcaft Syn-Blend
3) a)Pennzoil yellow bottle - b)Valvoline All-Climate

I never thought about doing it right after the oil change. Perhaps because the oil is just too darn hot.
shocked.gif
 
Quote:


Quote:


Yes, you read the title correctly.

Can someone explain what is the property of "slipperiness" as related to a PCMO oil and please direct me to the product data sheet number or ASTM test that measures this property/quality?




Would you like the results of that test to show the most slipperyness at cold start-up (or) normal engine operating temperature?
crazy.gif


My definition of cold-start slipperyness is something I have been doing for the past 30 years changing my own oil. Prior to pouring the new oil, I rub some (0W/5W/10W-30) on the tips of my forefinger and thumb. It's my own friction test - rubbing back & forth for around 10-15 seconds.

Which "COMMON-EVERYDAY FOUND" oils feel the slippery(est) between my fingers?
1) a)Pennzoil Platinum - b)Castrol GC 0W/30
2) a)Castrol Synthetic Blend - b)Motorcaft Syn-Blend
3) a)Pennzoil yellow bottle - b)Valvoline All-Climate

I never thought about doing it right after the oil change. Perhaps because the oil is just too darn hot.
shocked.gif





So, Triple, if I understand your comment, you are saying Passenger Car Motor oils do have a "slippery" property, it is measured with a "finger gauge" and your finger gauge has acurately ranked the above 3 motor oils.

Did I get that correct?

(Byranscfhr, I now can understand your comments RE: Leaving the Board!)
 
Based on your finding, I should
a. go another OCI with MC since its ranked #2
2. or go with PP using the BOGOF and get the best

Either way, I guess I have set myself up for continued success.

Thanks for posting your finger test. It is now the prototype test.
 
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