Using no more than logic, flawed or otherwise, it seems machine tools start of sharp, and after performing some number of cuts may well be re-sharpened or replaced. As I remember production, there were means of checking the quality of manufacturing at various processes to ensure acceptable tolerances were achieved..? I suspect much depends on whether the engineers are in charge or the bean counters to determine just how much "tolerance" might be acceptable..? Thus it seems that one engines oil pump gears may have a tighter mesh than another with the creation in variable outcomes as reported
Seems to me that the thinner the oil the easier task it might have in finding it`s way past the gears..?
I suspect thicker oils may not be an easy answer given the lubrication requirements of modern engines..?
