Join Date: Jan 2005
Car: Other Manufacturer. Previously - more Rovers than I care to remember.
The oil does indeed require surface texture in order to cling to the surfaces and lubricate them. Perfectly smooth surfaces tend to stick together when there is no oil, you can demonstrate this by twisting slip gauges together - they stick very well! This is why a burnished bearing surface will scuff up.
Metal particles in the oil? Most will be taken out by the filter, does it matter what kind of metal is left behind for this stuff to work or is it just "metal"?
We once performed a series of tests on engines using microfine diamond dust! This polished the working surfaces to a mirror finish, but produced no measureable extra power or any other improvement. However, it did wear the engine out after about 100 hours running ;-)