I would post this here as a graphic however with the new update to the forum it's not displaying well so here is a PDF instead, better this way because then you can resize to make reading it easier: https://drive.google.com/file/d/1rTVc4XEXLURbUZtqQDqCDazcbCUyWQV9/view?usp=sharing
Snippets:
Quote
... You might think it advantageous to throw out your 0w-20 motor oil and use 15w50 instead. That's a bad idea, and here is why.
Modern engines are built with tight clearances between parts than their predecessors. Let's take the GM 3.8L engines we test in our mechanical lab as an example. The clearances between the crankshaft journals and main bearings can be as low as .0007 inches. That's thinner than a sheet of paper (about .004 inches) ...
... Using a higher viscosity oil than what's recommended in your modern engine would lead to increased wear.
... Although oil film thickness is related to lubricant viscosity, film strength is a function of base oil and additive quality.
... Additives, too play a vital role in low viscosity oils. We talked about boundary lubrication earlier. When in a boundary lubrication situation, protecting against metal to metal contact falls on the motor oil's anti-wear additives, more so than with higher viscosity oils. The additives form a sacrificial barrier on metal parts that absorbs contact and protects the metal surfaces.
Apparently Japan is working on 0w8 oils (End of this article)!
Snippets:
Quote
... You might think it advantageous to throw out your 0w-20 motor oil and use 15w50 instead. That's a bad idea, and here is why.
Modern engines are built with tight clearances between parts than their predecessors. Let's take the GM 3.8L engines we test in our mechanical lab as an example. The clearances between the crankshaft journals and main bearings can be as low as .0007 inches. That's thinner than a sheet of paper (about .004 inches) ...
... Using a higher viscosity oil than what's recommended in your modern engine would lead to increased wear.
... Although oil film thickness is related to lubricant viscosity, film strength is a function of base oil and additive quality.
... Additives, too play a vital role in low viscosity oils. We talked about boundary lubrication earlier. When in a boundary lubrication situation, protecting against metal to metal contact falls on the motor oil's anti-wear additives, more so than with higher viscosity oils. The additives form a sacrificial barrier on metal parts that absorbs contact and protects the metal surfaces.
Apparently Japan is working on 0w8 oils (End of this article)!
Last edited: