Putting the Simple Back into Viscosity

[wwillson]

A great technical article from our friends at Lubrication Engineers.

Thanks to Paul at LE for letting us publish this fine article.

Putting the Simple Back into Viscosity

 

[INDYMAC]

There are some typo's in the cold temp testing sections (should be negative instead of positive numbers for reference temps). Otherwise, great addition to the BITOG library. Thanks for posting.

 

[wwillson]

Originally Posted By: INDYMAC
There are some typo's in the cold temp testing sections (should be negative instead of positive numbers for reference temps). Otherwise, great addition to the BITOG library. Thanks for posting.


Could you be more specific, I don't see the errors.

Thanks,

Wayne

 

[INDYMAC]

For the Brookfiled viscosity ASTM D2983 description I believe he meant to say temp ranges between 5C and -40C. Not 5C and 40C.

For the ASTM D4684 viscosity description I believe he meant to say final temperature range between -15C and -35C, and not 15C and 35C. I've also seen different numbers for this test.

It looks like the proof reading safe guard didn't work too well.

 

[wwillson]

I found those and a couple more. For some reason the editor must have stripped some of the "-" signs.

Thanks,

Wayne

 

[friendly_jacek]

the columns in the first table are wrong.

they read:
Kinematic Viscosity (cSt) at 100°C Max
Kinematic Viscosity (cSt) at 40°C Max

Should be"
MIN Kinematic Viscosity (cSt) at 100°C
MAX Kinematic Viscosity (cSt) at 100°C

it's more than simple editing errors.

 

[friendly_jacek]

I liked this part:

Quote:
A number of years ago, straight grade engine oils, especially SAE 30 and SAE 40, were the most prevalent viscosity grades used by most consumers. SAE is considering adding either two or three new viscosity grades to the SAE J300 Viscosity Classification that was described previously. (15) The reason all of this is occurring is because much attention is being paid to improving fuel economy and energy efficiency. Governments are pushing automotive and industrial OEMs to find ways to improve the efficiencies of the vehicles and equipment they produce. It is not completely surprising that lubricants have been considered as a means to decrease fuel and energy consumption. As viscosity is a measurement of the internal resistance of a fluid to flow, if the viscosity is decreased, then so is the internal resistance. Therefore attention is now being paid to decreasing the viscosity of various lubricants to reduce their detraction from efficiency. Improved efficiency results in less energy consumed, which results in lower emissions released into the environment.


I'm not against lower viscosity fluids (I use 0W20 in my Prius), but it should be understood why we use them.

I'm against the B.S. showing up in many BITOG threads that lower viscosity is to decrease wear.

 

[GMorg]

I agree with the sentiment above, but I am also not a fan of the idea that increased engine performance, including fuel efficiency is somehow a negative. If we really wanted to keep wear at a minimum at ALL costs, we would never start the engine.

 

[Soharu]

Great article. I think that I've found another typo.

"A more familiar viscosity term is kinematic viscosity, which takes into account the fluid density as a quotient of the fluid’s dynamic viscosity and is usually reported in stokes (St) or centistokes (1 St = 0.01 cSt)."

Aren't there 100 centistokes in 1 stoke? Isn't this analogous to 100 centimeters in a meter?

 

[MolaKule]

The white paper is here specifically:

http://www.lelubricants.com/lit/news/White Papers/simple_viscosity.pdf


"usually reported in stokes (St) or centistokes (1 St = 0.01 cSt)."

I think it meant to say:
Quote:
usually reported in stokes (St) or centistokes (1 cSt = 0.01 St).

 

[MolaKule]

Originally Posted By: friendly_jacek
the columns in the first table are wrong.

they read:
Kinematic Viscosity (cSt) at 100°C Max
Kinematic Viscosity (cSt) at 40°C Max

Should be"
MIN Kinematic Viscosity (cSt) at 100°C
MAX Kinematic Viscosity (cSt) at 100°C

it's more than simple editing errors.


Nope, Table 1 is ok as that is the usual presentation for viscosities.