When running the test with new oil, all factors are constant and controlled.
Running used oil introduces all kinds of uncontrolled elements--engine efficiency, engine maintenance, egr working or not, various types of driving, etc.
We can see some of this in the various posted oil analysis reports.
Speaking of 4 ball wear tests and its validity to engine lubrication rating, I have an incredible liquid that will post higher 4 ball wear numbers than any engine oil currently on the market. It is called Coca Cola. Coke is an unacceptable engine oil lubricant yet will post very high 4 ball wear numbers, significantly higher than any of the currently available engine oils. Point being, an engine oil that posts very high 4 ball numbers has no direct relationship to its performance as an engine oil lubricant.
I doubt Coke has any lubrication value or that any single test means a lubricate is superior.
However, the liquid that collects on the top of Ketchup is the best lubricate known to man, for everything. The only problem is, how do you get 4 quarts of the stuff?
You know, I think this post deserves the sacrifice of a few timken bearings (Heck I'll buy the bearings) to some household food products.
We can see how well Coca Cola fares against Pepsi Perhaps see if cooking oil will outperform Mobil1? I think it might show some interesting results...
Hey COCA COLA is easily procurable.......... and George says it does great on the 4ball........Amsoil uses 4 ball wear data to prove the superiority of the lubricant........???????..... Yes,Yes I think its our first ingredient! The "real thing".
The ASTM 4172, four ball wear test is simply a quick and dirty way of looking at the boundary lubrication properties of an oil. Oil analysis is a much better way of seeing how the oil does in actual service. George is correct, the phosphoric acid in coke will keep a one armed bandit from ever seizing up
The four ball wear test is certainly a valuable tool for use in developing lubricants, especially greases. My sharing of the Coke (and Chlorine bleach is even better!) was to point out that taking just one/that test as an absolute indicator of how well an engine oil will perform or using it as a gauge to compare with other oils, well, let's talk about Coke's performance....
I have a 4 ball machine in our lab and definately use it for our own comparative work, in fact it is well used but I will not be talking about any results with it for the aforementioned reasons..
We get a lot of "hmmm, that is very interesting" from the 4 ball and other tests, but the proof is in field performance. I have 6 inches of scar tissue from making lab assumptions and then having the lubricant proceed to totally fail in field operations..
Well said George ! I was testing a new grease in CV joints at Sebring International Raceway in 1998 and had a bearing failure at the apex of turn 10 or Cunniningham corner while pulling 3.5Gs lateral ( no banking). No scars though. I sure was surprised that the well made component totally separated after using the grease as a cutting oil. No brands mentioned under severe penalty of law.