[aerohead]

If the OEM design 'surface-roughness' of an engine's components are arbitrarily 'smoothed', you run the risk of losing the 'porosity' of the surface, and along with it, it's capability of maintaining an oil film.
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Lake Speed Jr., Tribologist for Joe Gibbs ( NASCAR ) Racing, and Lubrisol, was explaining this at, 'GEAR TALK' , Episode ##014.
Southwest Research Institute collaborated with Lake, on the 'synergy' of variable coatings, for optimized-ensemble, oil/ surface finish treatments, which ultimately allowed winning race seasons.
' If you can't measure it you can't improve it,' is Lake's mantra.
It made the difference between an engines 'lifespan' of 1-hour, to over 200-hours.
THEY HAD LOST ENGINES BECAUSE THEIR SURFACES WERE 'TOO SMOOTH'!