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#3272953 - 02/06/14 07:25 PM Re: Lower NOACK = Better Oil??? [Re: buster]
CATERHAM Online   content


Registered: 11/18/05
Posts: 9601
Loc: Burlington, Ontario, Canada
buster thanks for that link (quote), very interesting.
Although I suspect, if the test was done at normal hot operating temp's (200F-250F) even for an appropriate lengthy time period, the total volatility percentage would be still be lower than at the current 482F. The reason being that certain light fraction that do evaporate at the higher temp' wouldn't at the much lower temp' no matter how long the oil is cooked.
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#3273078 - 02/06/14 09:02 PM Re: Lower NOACK = Better Oil??? [Re: CATERHAM]
Shannow Offline


Registered: 12/12/02
Posts: 26818
Loc: a prison island
Originally Posted By: CATERHAM
It never ceases to amaze me how much you like to spread miss information. The December issue of Lubes "N' Greases has an interesting article titled "Volatility: The Inside Story", for those that want to read it.

Some basic facts.
Limiting engine oil volatility has everything to do with controlling oil consumption and oil thickening as a result.
A couple of quotes from the paper:
"The question was, how to maintain healthy engine oil viscosity when vapor losses kept eroding the oil in the sump?"

"Low temperature oil viscosity can suffer when vehicles operate under high-temperature conditions (which volatilize the light ends of the oil and lead to thickening)."


As an engineer, I was trained to go to references and papers not puff pieces...at University, it was explained that volatility of the lubricant in the hot cylinder was significant to the process, and that the issue was primarily cat life, not viscosity/economy

e.g. "Sources and Chracterisitcs of Oil Consumption in a Spark-Ignition Engine" - section 4.2...it's even got pictures

Originally Posted By: CATERHAM
buster thanks for that link (quote), very interesting.
Although I suspect, if the test was done at normal hot operating temp's (200F-250F) even for an appropriate lengthy time period, the total volatility percentage would be still be lower than at the current 482F. The reason being that certain light fraction that do evaporate at the higher temp' wouldn't at the much lower temp' no matter how long the oil is cooked.


Like I keep saying, it's NOT about bulk oil temperatures (and 20s that run so cool that it's not a problem)...

http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1634308

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#3273261 - 02/07/14 01:49 AM Re: Lower NOACK = Better Oil??? [Re: Shannow]
Shannow Offline


Registered: 12/12/02
Posts: 26818
Loc: a prison island
Originally Posted By: Shannow
e.g. "Sources and Chracterisitcs of Oil Consumption in a Spark-Ignition Engine" - section 4.2...it's even got pictures


Here's the buyable version

http://papers.sae.org/2004-01-2909/

You can google the title and find an MIU PDF.

Google link

At this point I will throw myself upon the mercy of BITOGers in dearest apology for continually spreading mis-information

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#3273291 - 02/07/14 05:00 AM Re: Lower NOACK = Better Oil??? [Re: Jeffs2006EvoIX]
Shannow Offline


Registered: 12/12/02
Posts: 26818
Loc: a prison island
http://www.savantgroup.com/ASTMSym04-PEI.pdf

gives the reasons for using Noack...followed by modified procedures.

Quote:
Association of Phosphorus Emission with Oil Consumption and Volatility - Oil consumption caused by oil volatility has always been a concern for automotive engineers because of the associated deposits often formed on piston rings and combustion chambers. Concern that oil volatility could cause phosphorus in the exhaust stream, added to the desire to reduce oil volatility. Consequently, progressively lower formulated engine oil volatility (as measured by the classic Noack volatility test [9-12]) was required for oils meeting API and ILSAC GF-2 (22% loss) and GF-3 (15% loss) specifications.


Same researchers...in "Phosphorus Emission Index (PEI) Studies Of ZDDP in Engine Oils" (Googlable, and has pictures)

Quote:
Temperatures of 250C at which the special Noack was normally run to generate PEI values (PEI250) reflected reported upper-cylinder, ring-belt temperatures


Demonstrates that longer exposure, at lower temperatures still liberated volatile phosphorus...

Both indicate that volatility and phosphorus levels don't either equal cat poisoning, but can be cumulative...and (really interestingly) that certain additive chemistries allow higher ZDDP species, with lower cat poisoning ability.

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#3274490 - 02/08/14 05:51 AM Re: Lower NOACK = Better Oil??? [Re: Jeffs2006EvoIX]
bobbydavro Online   content


Registered: 02/01/09
Posts: 111
Loc: 3rd rock from the sun
250C is the temperature of the NOACK test. Ring pack temperatures often exceed this, so yes Noack is releveant.

However two oils can both have a 10% NOACK but with a very different base oil mix. One could be all 5cSt base oil, the other a mix of 4 and 6 cSt. What is important for oil consumption is the smount of light ends as the engine is effectively a distillation tower.


The IIIGB is a Phos volatility test, important for catalyst protection, and has zero correlation with Noack





Edited by bobbydavro (02/08/14 05:52 AM)

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#3431880 - 07/22/14 03:07 AM Re: Lower NOACK = Better Oil??? [Re: CATERHAM]
Shannow Offline


Registered: 12/12/02
Posts: 26818
Loc: a prison island
Originally Posted By: CATERHAM
Originally Posted By: Shannow
It's obvious that some people don't get the concept of Noack...it's not something that has anything to do with the temperature of the oil in the sump...absolutely nothing to do with sump temperature...oils don't "run cool enough" for Noack to be irrelevant no matter how the science "feels"

It's supposed to represent what happens to the oil that is left above the rings on the downstroke (the rings are hydrodynamically lubricated on the upstroke when the piston speeds up, so the oil has to be the film that has been on the wall, exposed to the heat, oil pressure doesn't get it there).

Studies show that this oil is enriched in additives, so must be so as the oil evaporates off...smaller engines with greater BMEP are MORE likely to have cylinder temperatures that evaporate more.

Noack IS relevent, has nothing to do with sump temperatures and turbos

It never ceases to amaze me how much you like to spread miss information. The December issue of Lubes "N' Greases has an interesting article titled "Volatility: The Inside Story", for those that want to read it.

Some basic facts.
Limiting engine oil volatility has everything to do with controlling oil consumption and oil thickening as a result.
A couple of quotes from the paper:
"The question was, how to maintain healthy engine oil viscosity when vapor losses kept eroding the oil in the sump?"

"Low temperature oil viscosity can suffer when vehicles operate under high-temperature conditions (which volatilize the light ends of the oil and lead to thickening)."


Originally Posted By: CATERHAM
The Noack spec' of an oil doesn"t concern me much as it has no effect that I can detect, besides no synthetic has a poor Noack.
It is important to the OEMs primarily for emission control reasons and therefore if the oil is on a recommended company list it's Noack is acceptable.


http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3431515/Re:_Castrol_0w40_vs_Mobil_1_0w#Post3431500

Guess that you DID read the links after accusing me of continually spreading misinformation...

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#3431987 - 07/22/14 08:14 AM Re: Lower NOACK = Better Oil??? [Re: Jeffs2006EvoIX]
OVERKILL Offline


Registered: 04/28/08
Posts: 26459
Loc: Ontario, Canada
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#3431992 - 07/22/14 08:20 AM Re: Lower NOACK = Better Oil??? [Re: Shannow]
riggaz Offline


Registered: 01/26/10
Posts: 304
Loc: England
Originally Posted By: Shannow

It's supposed to represent what happens to the oil that is left above the rings on the downstroke (the rings are hydrodynamically lubricated on the upstroke when the piston speeds up, so the oil has to be the film that has been on the wall, exposed to the heat, oil pressure doesn't get it there).



Isn't that boundary lubrication?

I think engines are usually are a mix of hydrostatic and boundary.


Edited by riggaz (07/22/14 08:23 AM)

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