With Mobil One 5W-50 in my old FE 400 there is hardly any blow by at all and probably hardly any oil mist produced. There is absolutely no oil coming out of the vent tube at all, not even to moist the surface of the breather hose. It easy to imagine that not much oil mist is whirling around inside the rocker cover either, to lubricate the stuff in there. And yes, I have had tappets that had avalanching wear and had to be replaced before anything dramatic happened, they probably ran dry. One only lasted 6 hours and it turned blue. Apart from that I consider this oil to be the No 1 of the oils that are available locally for reasonable money. Where this oil actually reaches it seems to do a very good job.
Mineral long drain high preformance diesel oils that I have tried have not lasted as long as the Mobil 1 does and they have allowed the gear changing to get notchy at the end of each oil change interval. Also the clutch characteristics are a lot more in my taste with the Mobil 1 oil. But these mineral oils have produced oil mist enough to moist the breather hose and they do probably lubricate the tappets better because they actually get there. Any oil lubricates better than no oil, I think.
Regards
