NOACK # relationships?

Messages
204
Location
Cordova, TN
The NOACK number reflects evaporative loss of an oil but what else does it tell you about the quality or make-up of an oil? For example, Mobil seems to use top quality PAO and esters in its base stocks for Mobil 1 SS, has good HTHS, pour and flash point numbers, etc but has relatively high (about 9-11% on average) NOACK numbers compared to Amsoil and Redline (generally about 6%). Why might this be and what does it indicate as far as the oil's make-up?
 
Messages
3,845
A NOACK value of 15 % or less is splitting hairs IMHO when a oil is well formulated. It is but one view of a complex puzzle in formulating a oil. Oils may resist volatility very well and lubricate not so well. I see the good NOACK values rendered meaningless in oils that stand up over time but allow too high wear rates.
 
Messages
3,327
Location
Bolivia
This topic has some interesting threads from last year. Seems that on a lot of major brands what they publish is based more on being legally safe than stretching their claims or even claiming what they get.
 
Messages
485
Location
Montgomery, AL
Don't we need good solvency to keep the inside of the engine clean and keep deposits "in solution". I would imagine chemicals that provide solvency would be somewhat "volatile". Low NOAK is not the end all.
 
Messages
5,785
Location
Dixie
The amount of high temp evaporation is a function of both the basestock blend and the additive chemistry used. For example, some of the VI modifier volatilizes at high temps and is burned off - this is why the wide range grades like 0w-40/5w-50 have significantly higher Noack values than the 10w-40/20w-50 grades. Polyolesters have even lower volatility than do PAO's, so you see significant differences even amoung the various synthetic lubes. There are also different quality levels of PAO basestocks being used through the industry. All things being equal, higher molecular weight basestocks are more stable at high temps - this is also why a 20w-50 will always outperform a 0w-30 or 0w-40 when it comes to the Noack test. It is the low molecular weight fractions of petroleum lubes that readily evaporate at engine temps and result in oil consumption .... I am somewhat puzzled at the Noack differences between Mobil 1 and Amsoil, since Mobil has been their main supplier of PAO basestocks for over twenty years. I can only assume that Amsoil is using significantly more ester, or their additive chemistry is more thermally stable. The only Mobil 1 formulation that does really well on the Noack test is their 15w-50, which comes in at approx 5%. TooSlick
 
Messages
8,937
Location
SC
quote:
Originally posted by TooSlick: I am somewhat puzzled at the Noack differences between Mobil 1 and Amsoil, since Mobil has been their main supplier of PAO basestocks for over twenty years. I can only assume that Amsoil is using significantly more ester, or their additive chemistry is more thermally stable.
Or one could assume that their "superior" Noack numbers are just more marketing fluff and don't correlate to the actual numbers of the oils that are in the bottles consumers buy. Has Amsoil's Noack ever been independently verified, or do we just have the numbers Amsoil provides?
 

MolaKule

Staff member
Messages
21,716
Location
Iowegia - USA
"I am somewhat puzzled at the Noack differences between Mobil 1 and Amsoil, since Mobil has been their main supplier of PAO basestocks for over twenty years. I can only assume that Amsoil is using significantly more ester, or their additive chemistry is more thermally stable. The only Mobil 1 formulation that does really well on the Noack test is their 15w-50, which comes in at approx 5%." I think the difference is that Mobil uses higher viscosity PAO's and low viscosity esters, whereas Amsoil uses low viscosity POA's, and high viscosity esters. [ February 14, 2003, 02:18 PM: Message edited by: MolaKule ]
 

Jay

Messages
1,607
Location
Idaho Falls, ID
Good post Molakule, thanks. I think that explains why my car burns right through M1 0w-30 compared to M1 5w-30. I know it's not just me. Others with Honda's K20Ax engine report the same problem. M1 0w-30 must be using the lighter, more volatile esters to better the low-temp performance of this oil.
 
Messages
6,388
Location
Washington St.
Doesn't Amsoil need very low volatility rates more than other oils? They need to keep their high amounts of phosphorus out of the catalytic converters, and they need to keep their oil from increasing viscosity too much during their very long oil drain interval. Ken [ February 14, 2003, 12:56 PM: Message edited by: Ken2 ]
 
Messages
5,785
Location
Dixie
Ken2, One of the primary reasons why Amsoil has always stressed formulation oils with a low Noack # is to prevent oil consumption over long drain intervals. Like it or not, I have many customers who run out to the six month filter change without EVER checking their oil level. In some cases this can be as much as 12,000 miles, so if you were using an oil that evaporates readily, you could be several quarts low at that point. The other point you make about oil thicking is also valid, although not directly. One of the most effective antioxidants is ZDDP, so both Amsoil and Redline use a healthy amount. You want a high level of ZDDP in there to reduce oil thickening and provide wear protection over long drains, but you don't want it burning off and fouling your oxygen sensor and plugging up your Cat. Amsoil has worked very closely with Lubrizol to develop oil additive chemistries that have excellent high temp stability. In fact Amsoil was the first US oil company to use the Noack test on a routine basis - as you may know this test originated in Europe. Most folks running Mobil 1 change it every 4000-6000 miles, so developing a very low volatility oil isn't as much of a design driver for them. They could certainly do it, but it would be more expensive .... TooSlick
 

MolaKule

Staff member
Messages
21,716
Location
Iowegia - USA
TooSlick, "One of the most effective antioxidants is ZDDP, so both Amsoil and Redline use a healthy amount. You want a high level of ZDDP in there to reduce oil thickening and provide wear protection over long drains, but you don't want it burning off and fouling your oxygen sensor and plugging up your Cat." ZDDP is the cheaper route to anti-oxidants. Effective antioxidants are also Moly and Antimony dialkydithiophosphates, which when formulated with calcium additives, provide the combined effect of reducing nitrous oxides and lessening catalytic poisoning by ZDDP. For ZDDP, antioxidation is a secondary function of this additive. The primary function is to reduce wear as an AW additive. Schaeffer's petro's and blends go comparable distances with full synthetics because of their Moly and Antimony dialkydithiophosphates and their penetro additves, all which reduce help reduce oxidation and thermal degadation of the base oils. [ February 18, 2003, 02:42 PM: Message edited by: MolaKule ]
 
Top