One for the Techies

[JTC]

web page on 5w-20

This site is Korean, and contains, evidently, a paper on the development and testing of modern 5w-20 oils. The text is unreadible, but the charts are in English and contain some interesting test reports of 5w-20 vs. 5w-30 using improved (group 2?) base oils and additives. I think it is saying that such a 5w-20 does as well as older 5w-30, but a 5w-30 is still better if formulated with modern base stocks and additives.

Isn't it interesting what's on the web.

 

[sprintman]

MK
Thats why I think M1 SS is ready for GF-4. Might not 'plate up' on a Timken but maybe any GF-4 oil won't? All supposition till GF-4 arrives I guess.

 

[jjbula]

The charts seem to show HTHS viscosity as having a direct effect on Bearing rod wear. Maybe the Europeans have something with their >3.5 HTHS requirment for A3 oil.

 

[MolaKule]

It is difficult to decipher. So how does one improve on dino base oils?

He doesn't, he just builds better additives.

You might be suprised to discover the intense research going on with oil additives and with oil additive interactions. With GF-4 looming on the horizon, a lot of additive optimization is being done to determine the best package with repsect to lowest cost.

 

[Fillherup]

Hi, I am a new member.

I pulled down a SAE paper #980702 'Properties of Engine Bearings Lubricated with Low HTHS Viscosity Oil' before I joined this forum. It clearly states that "The wear amount of bearings were well correlated with HTHS viscosity, not with kinematic viscosity."

The relationship of HTHS to wear is well understood. Why does kinematic viscosity not track well with wear? A related question is how do some 10w-30 oils have higher HTHS specs with the same 30 weight viscosity? Most 30 weights seemed to be around 2.9- 3.2, but some go all the away to 3.5.

FYI, the paper tested oils with HTHS from 1.8 to 3. The knee of the wear curve was around 2.5-2.6, i.e. the same as most 20 weights today. The curve starts to flatten around 3. I wished they had tested a really high HTHS around 4-5 as a reference.

Thanks Great forum!

[ February 05, 2003, 11:25 PM: Message edited by: Fillherup ]

 

[G-MAN]

quote:

---

Originally posted by Fillherup:
Hi, I am a new member.

I pulled down a SAE paper #980702 'Properties of Engine Bearings Lubricated with Low HTHS Viscosity Oil' before I joined this forum. It clearly states that "The wear amount of bearings were well correlated with HTHS viscosity, not with kinematic viscosity."

The relationship of HTHS to wear is well understood. Why does kinematic viscosity not track well with wear? A related question is how do some 10w-30 oils have higher HTHS specs with the same 30 weight viscosity? Most 30 weights seemed to be around 2.9- 3.2, but some go all the away to 3.5.

FYI, the paper tested oils with HTHS from 1.8 to 3. The knee of the wear curve was around 2.5-2.6, i.e. the same as most 20 weights today. The curve starts to flatten around 3. I wished they had tested a really high HTHS around 4-5 as a reference.

---

It seems, then, that what this study probably shows is that once you get an HT/HS over 3, the advantage of having a higher HT/HS oil in relation to bearing wear gets less and less.

 

[nick778]

Does anyone know what xxw-30 synthetic oils have a HTHS rating above 3 and above 3.2? It would be interesting to know what they are and what the rating is.

 

[rugerman1]

nick778
HTHS thread

Mark

 

[RB Shannon]

Fillherup,Where did you get your SAE paper from,I couldn't find it on the SAE site

 

[MolaKule]

The latest HTHS tests seems to correlate well with hydrodynamic oil film thickness under high temps and high shear.

 

[Fillherup]

RB Shannon - I pulled it down about a year ago, when I get a chance I will scan the site again.

One good thing about ordering several SAE papers is that I still get SAE catalogs in the mail. Some are quite huge.

It seems that HTHS is very important. I wonder why the focus is not more on this in ranking an oil. The focus on UOA/VOA is always kinematic viscosity not HTHS. It is a testing issue or does HTHS never change with use?

G-Man II- It seems to me considering the trade-offs of wear and CAFE, the trend today is not to have high HTHS. But just use todays better BL additives to compensate for the lower HTHS and evitable lost of the hydrodynamic oil film under stress conditions. After reading this forum and the SAE paper, it just might be better to have superior backup BL additive instead of trying to get lower wear by HTHS. It does little to nothing for cold starts ( maybe even worse) and hurts gas mileage. All the focus on 20w oils probably takes this into consideration and gives for most drivers equivalent performance as yesterdays 30w oils.

Of course, if this assumption is right, then I can make intelligent decision based on my driving conditions or really take advantage of the new BL additives and get even greater performance. Some folks on this forum are doing this already by making their own blends with stuff like #132. I tend to agree now. Just not sure of the risk, required treatment levels or frequency needed to maintain the BL.

[ February 12, 2003, 06:55 AM: Message edited by: Fillherup ]

 

[Fillherup]

RB Shanno- Paper still onsite. See below:


SAE Technical Papers
--------------------------------------------------------------------------------
Document Number: 980702

Title: Properties of Engine Bearings Lubricated With Low Hths Viscosity Oil

Meeting Where Presented: International Congress & Exposition, February 1998, Detroit, MI, USA, Session: Advanced Materials For Automotive Applications