Validity of the "4-ball" wear test in engine lubes

[Shannow]

Was reading an old(ish) oil manual in tha bath a few weeks ago, and came across a 4 ball wear test minimum in "Engine Oils"...turned out to be steam "Engine Oils", and in the boundary, wick lubricated parts of the engine, not the steam parts...VI was not to be below 50 unless the OEM specified it.

 

[Garak]

So, you're saying that OEMs may have specified a VI at least at one point in time?

 

[Shannow]

LOL, yep, foist on my own petard so to speak...when we return to steam engines, maybe it will come back.