Dangers of low viscosity oils a problem waiting to happen?

[DirectRejection]

The repetitive posturing on this board is along the lines that dexos1 Generation3 0W20 is not adequate for a 2024 Silverado.

Of course ILSAC GF-6A is backward compatible and GF-6B is not.

SP 0W20 might be but not necessarily be equivalent to SN 0W20.

There is cherrypicking of facts around here, based upon viscosity.

 

[Al]

Don't worry about fulm film or really no film at startuhttps://www.foxnews.com/video/6363202986112. There is no load on the bearing.
And again 20 wt oils and lighter are to a large degree for cooling. and carrying the anti=wear/anti-friction additives. The real protection is from the moly, boron, and ZDDP. (IMHO)

 

[oil pan 4]

I wonder if the oems are using nitrided crankshafts.

GM used nitrided cranks in the 1980s.

 

[oil pan 4]

Yeah I'm just going to pick oil that makes around 10cSt at operating temperature and stays above 2.7cP under HTHS conditions.
If it ain't broke don't fix it.

 

[MolaKule]

Don't worry about fulm film or really no film at startuhttps://www.foxnews.com/video/6363202986112. There is no load on the bearing.
And again 20 wt oils and lighter are to a large degree for cooling. and carrying the anti=wear/anti-friction additives. The real protection is from the moly, boron, and ZDDP. (IMHO)

?? https://www.foxnews.com/video/6363202986112 is about breast cancer awareness. ??

There is always a load on the bearing whether in motion or not; it's just that the load varies dynamically in journal and wrist pin bearings when in operation. It is only during motion that the wedge-type geometry film develops.

Even when there is no motion, a film resides in and between the journal and the bearing, albeit a thin film.

 

[SammyChevelleTypeS3]

There is nothing wrong with 20 weight oil. Those Ford LTD taxis with 400k+ miles on their odometers that seem to still be servicing small towns in the US are all speced 5W-20.

I believe 20 weight oil is adequate, 30 weight oil in Optimal. But since the cost is the same, I prefer 30 weight with it's higher HTHS.
Most countries in the world specify 30 weight as the lowest allowable viscosity in their owners manuals.

Exactly. I been using the spec 5w20 motor oil in our 2009 Honda Accord, used it for 18 years in the 2002 we finally sold off. Never had any engine issues using it. The ONLY reason I questioned it a few years back was when the wife ended up with a GDI-T engine car while I was in and out of hospital and did not have any time to research that type of engines. Had I known anything about them I would have not let her purchase the car for ONE reason only. The fuel dilution in the oil thing that Honda has done their best to deny is even happening in some of their vehicles. They have been forced to acknowledge it in the CRVs and also in China and a few places. Yet , since we have the car and I learned about them I am simply doing shorter oci and keeping every maintenance item I need to attened to when needed. We have put probably over 50,000 since she bought it and not one issue to complain about. I change the oil / air filters and have replaced the PCV once so far and it was not bad. Agree. There is no evidence that something is wrong with 20weight motor oils.

 

[wpod]

Psh, IIRC HPL or @RDY4WAR said Pro Stock oil has been 0w2 for awhile.

Are Pro Stock engines expected to last over 100,000 miles?

 

[nascarnation]

Are Pro Stock engines expected to last over 100,000 miles?

Only if you include mileage accumulated in the transport trailer.

 

[Ride_Red]

That seems counter-intuitive. Adding cost and weight seems like it would offset any gains from the low viscosity lube.

Sure, it kinda seems that way.
You can see an obvious change from older engines to newer engines by looking at the connecting rods. Older engines had smaller crank bearings (with the caps cut at 90 degrees from the rod). New connecting rods have larger diameter crank bearings and the caps are cut at 45 degrees so that the the cap bolt flanges fit down through the cylinder bore.

 

[Shel_B]

Although the oil film may be weaker on that bearing surface, there is a larger surface area bearing the load to make up for it. You can still run a thicker oil in the new engines, but you shouldn't run the thinner oils in an older engine.

That seems counter-intuitive. Adding cost and weight seems like it would offset any gains from the low viscosity lube.

The use of "wider" bearings has been discussed here before, and it seems that such bearing design, along with quite a few other engineering and design approaches, contributes toward making these thin oils work.

 

[kschachn]

The use of "wider" bearings has been discussed here before, and it seems that such bearing design, along with quite a few other engineering and design approaches, contributes toward making these thin oils work.

Such changes help to keep wear to an acceptable level under most circumstances.