4-ball wear test - why no good?

[Pablo]

Originally Posted By: FrankN4
So this actually means that the 20W-50 MCV I used in the Honda was actually giving better wear protection than many heavy duty greases since it has a better 4-ball scar than many greases?

I don't get it. What if I decided to rub two aluminum arrow shafts together under laboratory controlled conditions with different lubricants and measure the wear. Would the one with the least amount of wear be no better than the one with the most amount of wear? Why?


It would tell you something about the lubricant, but it may tell you nothing about how the lubricant would behave in an IC engine.

 

[Shannow]

Originally Posted By: Pablo
I suppose you didn't believe this since it was real life: 409,000 mile drain interval


with statements such as
Quote:
“Again, very, very light wear. These could be
put right back in and used again. In an extended drain program [with petroleum oil] there’s a possibility you could see maybe half again as much wear.”
– Independent engine rater


Stating that wear is comparable to the same mileage on dino (albeit with more oil changes), comparing UOA against OEM condemnation limits as evidence of improved performance, it looks like...an advertisement.

 

[Pablo]

Originally Posted By: Shannow


Stating that wear is comparable to the same mileage on dino (albeit with more oil changes), comparing UOA against OEM condemnation limits as evidence of improved performance, it looks like...an advertisement.


That's because it is. But it is true.

 

[wgtoys]

The question for any bench test is: Is this test relevant to the actual target application?

In other words, does a good performance on this test accurately predict good performance in the intended real world application? Conversely, does poor performance in the test accurately predict poor performance in the real application?

So my question to the Amsoil defenders is this: Do you have evidence that 4-ball wear testing of motor oils is directly indicative of how well the lubricant performs at minimized wear in real engines in real vehicle applications?

It seems that the vast majority of the lubricant and engine manufacturing industries have concluded that the 4-ball test correlates poorly with real motor oil applications.

 

[Doug Hillary]

Hi,
Pablo - We are off the "balls" now are we?

Well the Amsoil advertised 409k OCI on a problematical Mack motor is indeed a talking point - for a Thread placed in the correct place of course - the Trucking Forum!

Oh - no oil consumption rates were mentioned, now that's a point Pablo isn't it. I have a customer here who uses a Shell HDEO in a number of his Cummins engines and doesn't change it either. The planned top up rate is about 1 litre per 1k kms. That's equivalent to an OC at around every 38kkms, but he hasn't changed the oil - just consumed it!

And yes I am very sceptical about such claims because I have NEVER seen them translated into real life usage in the real world where I live

 

[Pablo]

Originally Posted By: Doug Hillary
Hi,
Pablo - We are off the "balls" now are we?

Well the Amsoil advertised 409k OCI on a problematical Mack motor is indeed a talking point - for a Thread placed in the correct place of course - the Trucking Forum!



Originally Posted By: Doug Hillary earlier in this thread
Oh and what about the 400k HDEO OCI.....

 

[Tempest]

Originally Posted By: CompSyn
If you’re driving a modern vehicle with OEM rollorized valve train, the metal to metal wear test doesn’t have too much merit. However, for those of us who utilize flat tappet camshafts in off road racing with radical lobe profiles and hundreds of pounds of valve spring tension... Huge merit.

Exactly.

 

[Shannow]

Not sure about that.

lifter bores are offset, cam lobes are tapered, and followers have rounded feet to ensure rotation, rather than 4 ball fixed geometry.

 

[Gary Allan]

Well, if it will make anyone here feel better, you are now allowed to envision tote size containers of sludge pouring down on you from above ..and you can also imagine sheared polymers reforming after being put through a shredder.

If anyone gives you any static about it, you tell them that Gary Allan said it was okay.

 

[buster]

http://www.gf-5.com/the_story/testing/#SequenceIIIGengine

These are the tests used that determine engine wear.

 

[jerre310]

At least Amsoil dealers don't run around using the one arm bandit testing machines and egg beaters to demonstrate their oils, like my local Schaeffer's and CenPeCo dealers.

 

[buster]

Quote:
A Falex Thrust Washer Machine in the 4-ball test configuration was used for evaluating friction and wear. These tests were run by rotating one steel ball against three stationary balls while adding load (weights) in increments. This step-loading sequence (described in ASTM D-4172) determines the coefficient of friction (COF) versus load to the point of failure or “incipient seizure.” FIG. 3 shows a typical friction plot for a 4-ball test and illustrates the typical effect of load on coefficient of friction. Each of the plots shown in FIGS. 3-7 can be divided into four regions. In the first (hydrodynamic) region, there is not any contact between the steel surfaces. The only resistance to sliding is due to the lubricant viscosity, and thus, the COF is very low (less than 0.05). The viscosity of the lubricant in this region is high enough to separate the metal surfaces. In the second region (the lubrication or boundary regime) the metal surfaces are in slight contact and the lubricant is only partially able to support the higher imposed load. At this point, there is a small wear scar forming on the steel balls. The viscosity of the lubricant is barely able to support the much higher load. Not only is the load very high but also the frictional heating has reduced the oil viscosity significantly. In the third region, the anti-wear additives in the formulation take over the task of preventing catastrophic wear by forming alloys with steel that allow the steel to continue sliding with relatively low friction. As the anti-wear additives are used up or decompose at higher temperatures, the steel reaches close to its melting point and would weld together except that the test is stopped before this occurs.


http://www.freepatentsonline.com/y2006/0105920.html

 

[TeeDub]

Anyone with a back ground in engineering understands the concept of an "analog" test, which is what all these ASTM tests are. This is true whether you're talking about the four ball test, the Noack volatility test, the CCS cranking test, or a high temp, high shear viscosity test.

The idea of an analog test is to roughly simulate one particular aspect of the operational environment for a particular material and/or process. None of the analog tests used for engine oils replaces engine sequence tests, but they do augment those tests and give you some idea as the the relevant properties of the lubricant. Of course you have to know which properties are relevant for a particular application and which are not.

The four ball wear test is actually a decreasing load test, since the wear scar diameters grow over the course of the test and the load carrying area between the balls increases - so the pressure in psi drops. Once you reach a condition where the particular additive chemistry can sustain the load (or a hydrodynamic state is achieved), the scars stop growing on the three test balls.

 

[digitalSniperX1]

I have a background in engineering. Electrical however, not mechanical.

How does this test simulate anything that goes on in a typical automobile engine? Are there wearing surfaces with areas that are infinitesimal?

Not knowing exactly what the test entails, if we're talking 'balls' wearing on each other and/or some other contact surface, and since the contact surface area is diminishingly small when there is zero wear assuming these are perfect spheres, and increases with wear, thus decreasing pressure, where in a automobile engine are we likely to encounter such a situation?

Also, the tests run for 1 hour, they don't necessarily indicate that the wear scar doesn't increase after one hour, or do they?

If not, what engine parts can sustain over time any kind of wear approaching 0.4mm in an hour? and at 1200 RPM (or is it 1800)?

Someone in this thread said this is not an extreme pressure test (however 4 ball wear tests are in fact used in extreme pressure tests as I'm sure the forces are simply increase with respect to some ASTM designation). Any test involving just about any amount of force exerted over a diminishingly small surface area would classify as 'extreme pressure', would it not?