This recent data caught my eye as I was looking at some of the recent GC, 0w-30 analysis results ....
ASTM D-4172B, Four Ball Wear Test
40kg pressure @ 150C, 1800 rpms for 1 hour duration
Amsoil 0w-30/TSO..........0.37 mm
Amsoil 5w-30/ASL...........0.40 mm
Syntec, 10w-30...............0.45 mm
Mobil 1, 5w-30................0.67 mm
Yes I realize this isn't the GC, 0w-30 formulation - it's the Group III based, garden variety Castrol Syntec. However, oil manufacturers generally use the same type of AW additive package for their gas engine oils, and the same type of additive package for their diesel oils.
The ASTM D-4172B test isn't really sensitive to the type of basestock used and it's even fairly insensitive to variations in oil viscosity. What it does do is give you a general idea of how effective the AW additives are under conditions of boundary lubrication, sliding contact and very high pressures. In other words, there is some correlation to valve train wear in an actual engine. Before anyone points out that engines don't use ball bearings, I suggest you do some research into the accepted practice of using analog tests throughout the field of materials science and mechanical engineering. You will find they are used all over the place ....For example, the Four Ball Test is required as part of the Mercon V transmission spec.
Given the precision of this test, variations of < .05 mm typically aren't considered significant.
For all practical purposes, the GC 0w-30 and the Amsoil 5w-30 generate comparable results in this analog test.
I eagerly await the all too predictable shrill response from the Mobil 1 crowd. However, I honestly think this helps explain some of the variability we see with regards to valve train and ring/cylinder wear seen in oil analysis testing.
TS
ASTM D-4172B, Four Ball Wear Test
40kg pressure @ 150C, 1800 rpms for 1 hour duration
Amsoil 0w-30/TSO..........0.37 mm
Amsoil 5w-30/ASL...........0.40 mm
Syntec, 10w-30...............0.45 mm
Mobil 1, 5w-30................0.67 mm
Yes I realize this isn't the GC, 0w-30 formulation - it's the Group III based, garden variety Castrol Syntec. However, oil manufacturers generally use the same type of AW additive package for their gas engine oils, and the same type of additive package for their diesel oils.
The ASTM D-4172B test isn't really sensitive to the type of basestock used and it's even fairly insensitive to variations in oil viscosity. What it does do is give you a general idea of how effective the AW additives are under conditions of boundary lubrication, sliding contact and very high pressures. In other words, there is some correlation to valve train wear in an actual engine. Before anyone points out that engines don't use ball bearings, I suggest you do some research into the accepted practice of using analog tests throughout the field of materials science and mechanical engineering. You will find they are used all over the place ....For example, the Four Ball Test is required as part of the Mercon V transmission spec.
Given the precision of this test, variations of < .05 mm typically aren't considered significant.
For all practical purposes, the GC 0w-30 and the Amsoil 5w-30 generate comparable results in this analog test.
I eagerly await the all too predictable shrill response from the Mobil 1 crowd. However, I honestly think this helps explain some of the variability we see with regards to valve train and ring/cylinder wear seen in oil analysis testing.
TS