Honda Civic EXT 1.5t UOA

[oil_film_movies]

Originally Posted By: danielLD
I thought you were trying to say you can use the Stribeck curve to calculate fuel dilution. If I misread then that's all.
Just saying viscosity is important, and the Widman Viscosity Calculator gives some insight into how much gasoline is mixing in the oil.
Again, I mentioned the Widman earlier.
Originally Posted By: oil_film_movies
I think you mean my use of the http://www.widman.biz/English/Calculators/Mixtures.html .
You can put in the kv100 of the new oil, then put in the kv100 of gasoline, and mix them until it equals the current used-oil kv100, indicating how much gasoline might be mixed in. This may be thrown off if there are more than 6,000 miles, since oxidation will increase viscosity after about that point.
Its a rough measure of how much fuel might be present, but you also have to take into account an expected loss from VII permanent shear.
One can play with the numbers to get some idea, but nothing too accurate.

 

[Nickdfresh]

Originally Posted By: oil_film_movies
...

TBN readings use a more reliable, accurate test. Similar to the good accuracy of viscosity measurements, so we trust them more.


Why? Based on what?

Quote:
Thanks for saying the 0w oil could have permanent shear. However, if kv100 really drops a lot, it can't ALL be from permanent shear, its probably half and half sometimes fuel dilution plus VII permanent shear together.

I have to think Honda knew about this reduction in viscosity (whatever the combo on causes), as they do a lot of durability lab and field tests before any consumer buys the engines.


Or maybe the viscosity was wrong and fuel dilution reading was correct?

You're just cherry picking...

 

[Nickdfresh]

Originally Posted By: Shannow
I'm intrigued with how his lab used the stribeck curve in order to come to the conclusion that it's wrong.

Pray tell exactly how it was applied to the field of Used Oil Analysis, because I'm scratching.

Stribeck explains the transition from fully blown hydrodynamic, through to the point that additives become the dominant driver of wear...

Here's a test result of a taxi fleet...

Per the description of the paper...

Quote:
Two programs were conducted to study the relationships between engine oil rheology and crankshaft bearing wear. A Chassis Dynamometer test of four oils in four cars was used to explore and define the key variables affecting bearing wear. These results were used to design a Field Test of nine oils in 45 taxicabs in New York City. The test oils (SAE OW-20 to 20W-20) were formulated to measure the effects of viscosity, viscosity index improver, and detergent inhibitor package. Bearing wear tended to be either low and unremarkable or very high, particularly in the thrust bearings. Oil performance was best expressed as the frequency of excessive wear, rather than by quantitative wear measurement. There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. Non-Newtonian oils appeared to provide slightly more protection than Newtonian oils of the same HTHS viscosity, and a higher quality adpack also appeared to provide benefits. However, these factors were secondary to the viscosity of the oil. HTHS viscosity was a better predictor of bearing wear performance than oil film thickness.


That's the stribeck curve explained...


Thanks for the 25 year old paper!

LOL who had 0W-20 in 1992? [censored] if I know!