Mobil 1 Extended Performance More Engine Wear

[Pablo]

Good stuff Tom. Thanks!

Quote:
I really question the repeatability of the test.


From this thread (yet another 4 ball test discussion)

 

[crinkles]

Originally Posted By: Tom NJ
A few relevant points on the 4 Ball method under ASTM D4172:

1. This method is for "fluids" (unspecified), not grease, and therefore is valid for motor oils:

1. Scope
1.1 This test method covers a procedure for making a
preliminary evaluation of the anti-wear properties of fluid
lubricants in sliding contact by means of the Four-Ball Wear
Test Machine. Evaluation of lubricating grease using the same
machine is detailed in Test Method D 2266.

2. The ASTM method calls for 1200 rpm, not the 1800 rpm used in the Amsoil paper:

4. Summary of Test Method
4.1 Three 12.7-mm [1⁄2-in.] diameter steel balls are clamped
together and covered with the lubricant to be evaluated. A
fourth 12.7-mm diameter steel ball, referred to as the top ball,
is pressed with a force of 147 or 392 N [15 or 40 kgf] into the
cavity formed by the three clamped balls for three-point
contact. The temperature of the test lubricant is regulated at
75°C [167°F] and then the top ball is rotated at 1200 rpm for
60 min. Lubricants are compared by using the average size of
the scar diameters worn on the three lower clamped balls.

3. The Repeatability of the ASTM 4172 method is 0.12 mm:

11.1.1 Repeatability
The difference between successive results obtained by the same
operator with the same apparatus under constant operating
conditions on identical test material would, in the long run,
in the normal and correct operation of the test method, exceed
the following value only in one case in twenty:

Repeatability = 0.12 mm scar diameter difference

This means that all results between 0.35 mm and 47 mm for a single run are considered the same.

Source: http://www.dieseltechsolutions.com/files/FE26PremierTestBooklet.pdf

Tom NJ


great post, thanks. my first reaction when i saw the chart was the readings were so close, its a wash.

 

[FZ1]

Dadgum,man. Thanks.

 

[erogers]

That document gives us quite an education! So in other words, virtually all of the oils shown in the test fall within a range that would be considered the same, given the repeatability factor. I guess it's not so much what Amsoil shows us on that page...it's what we don't know about the test, assuming the average Joe won't understand how to interpret the results.