Moly for the WIN. Probably the thing that needs Moly the most are the needle bearings in the roller lifters. But it can also help with the bearing surfaces as well. Back in the motor building days, that is all we used was Moly for engine assembly. \Lucky thenerdspetrochemical engineers and tribologists that work for the oil companies have figured out that moly can replace zinc and restore most of the lost lubricity from an additive standpoint, but so far there is just no replacement for viscosity (but man do they keep trying).
There is nothing new, nothing cutting edge, nothing unique about the lower end/ rotating assembly of the 6.2, its good old proven technology. The only difference is the thin oil (see there is no replacement for viscosity yet statement above).
But now, a problem that just didn't really exist before (main and rod bearing failures) has suddenly re-appeared. It must be just a strange coincidence that it happened at the same time that thin oils started getting spec'd by your logic.
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The only engine failure happened when a buddy was helping someone I know build a motor. He told the guy to grab the can of Moly in the tool box and lather up the camshaft. WELL it turned out the guy grabbed the same size can of VALVE GRINDING COMPOUND! Probably a few beers involved? Opppps, was rather sad because this was the guys biggest investment into a big block to date.
While 0W20 by itself it not so bad, borderline IMHO, the problems start when fuel contaminates the 0W20 engine oil, then there is NO safety margin. 0w20 turns quickly to 0W10 or just 0 weight engine oil. Not ideal for a torquey V8 or even something like a high strung turbo 4 cylinder. The problem is there is not a fuel sensor in the crankcase to turn a light on or to trigger the Oil Change Reminder. Even then, most people, your typical owner, will get around to changing the oil when they get around to it.
5W30 or 0W40 will give a much greater safety margin when it comes to contaminated fuel and the severe bearing loading on higher torque engines that are lugging around at 1500 RPM.
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