The real reason millions of engines are being recalled
(link)
None of these articles are fully on point. The writers still don't know the difference between 'tolerance' and "clearance". The MAIN CLEARANCE to be tightened was piston clearance. Use of hypereutectic pistons fit under .015" on a 4" bore and newer ultrahigh silicon content forging alloys. Bearing clearances are still about a thou per inch of journal diameter.
This motor, the 3A92, mine, calls for a 0W20 oil. The chart here shows three different viscosities used in this motor. 0W20 line if from Blackstone's library. The 5W30 from an acquaintances motor who is as annal as I, and the last, 5W40 my personal motor. The "Total Wear Metals" chart I posted earlier in this thread.
Chart I haven't posted is the Iron level chart. What it showed was that bore wear was reduced by using 5W30 over 0W20 but little more was gained in the use of 5W40. Almost all of the Total Wear Metals reduction comes from the huge reduction in piston skirt wear....aluminum. Bearing wear is reduced with each increase in HTHS viscosity so a smaller portion of the total wear improvement comes from that.
Piston cleanliness has next to nothing to do with an oils viscosity. Cleanliness or lack thereof is a ring killer, a VVT-AFM-DOD solenoid killer and a cam chain eater.
The posted link hints at manufacturing putting the viscosity cart before the ability to keep it clean enough to support that weight horse. That has absolutely zero to do with piston wear. But skirt and land wear have EVERYTHING to do with ring stability and longevity and control therefore of blowby.
Dirty assembly will kill any engine on any weight oil. If the culprit is surface finish then viscosity is a card to be played.
Use the information as you see fit.