The proof is to look at how the test is configured and compare it to the type of lube situation you see in the valvetrain. For example, the type of wear you see between a cam lobe and valve lifter is sliding contact under very high pressures in the 30ksi to 50ksi range. This is exactly what the Four Ball test is supposed to analog. The four ball test has no relevance to bearing wear since that's a full flow situation.
I've been a rocket propulsion engineer for the USAF and NASA for over twenty years and my educational background (MSME, Georgia Tech, 1981) is in materials science. In fact, I taught the subject as a GTA at Georgia Tech. With all due respect, I do believe I'm qualified to evaluate the veracity of a simple lab test. I've spent hours thinking about this test and I believe my conclusions are perfectly valid.
Tooslick
I've been a rocket propulsion engineer for the USAF and NASA for over twenty years and my educational background (MSME, Georgia Tech, 1981) is in materials science. In fact, I taught the subject as a GTA at Georgia Tech. With all due respect, I do believe I'm qualified to evaluate the veracity of a simple lab test. I've spent hours thinking about this test and I believe my conclusions are perfectly valid.
Tooslick