SAE Paper on Engine Wear with 20 wt. oil

[kschachn]

I think I have the understanding to say that the above example does not apply, is simply physics

I think you mostly quote things you find on the Internet.

 

[CarfriendXX]

You are welcome to explain to me how a 3-5 mm2 thicker oil stays longer in the bearings than thinner engine oil, I'm curious


Practice shows extensively how well these thinnest oils work, and this is practice and not theory

 

[kschachn]

You are welcome to explain to me how a 3-5 mm2 thicker oil stays longer in the bearings than thinner engine oil, I'm curious


Practice shows extensively how well these thinnest oils work, and this is practice and not theory

But see the problem is there have been more than one person in these discussions with you that have explained things to you in the past. You do not listen and appear to be so lost on basic technical principles that it’s not with the effort.

You remind me very much of a previous member here that is no longer with us.

 

[CarfriendXX]

All right. Thank you for your "not" explanation. But all theory. The topic is for me through...

 

[FishFry]

There is no simple answer - it all depends on your engine.
A pre war engine is totally different from one of the 80s or 2000s and if you have a new engine, where they used a plasma spray bore process it's a whole different game again, and what works for a 10 or 20 year old engine, doesn't work for a modern engine anymore.

Most people don't like the new trend toward lower viscosity engine oils - and there are some good reasons when you have an older motor.. But in some cases, there are actually good reason to not increase the oil viscosity beyond the spec that has been determined by the OEM. Lake Speed Jr talks about the new cylinder finishing technologies that are helping to enable low viscosity oils.

 

[SubieRubyRoo]

All right. Thank you for your "not" explanation. But all theory. The topic is for me through...

I explained a main reason why they’re chasing thinner startup oils, and it is physics, and again shows where you’re ignoring facts. Thicker oil takes more power to drive the PD oil pump. More power to turn the pump requires more fuel. Thinner oil saves fuel, at the expense of wear. Saving fuel (on paper, not exactly in the real world) is the goal of CAFE; they don’t care if your engine could have lasted 2x or more mileage on a thicker oil. This is not saying you will see an immediate failure from thinner oil, but there will absolutely be a difference in measured wear on 2 identically operated engines with one oil run on a 2.6 HT/HS and one with a 3.5 HT/HS oil for say, 200k miles.

A minimum HT/HS of roughly 2.6-2.7 is needed to prevent increasingly excessive wear, and most of the “performance” European oils require 3.5 HT/HS with at least 2.9 on the lowest 20wts (which borders on 30wt HT/HS anyways). This is why most people (and oil experts) feel that a non-fuel-diluted 30wt (~2.9-3.5 HT/HS) is optimal for most engines, and engines that are spec’d for thinner oils have moved towards wider bearing surfaces to spread the load so that MOFT can be maintained. That’s physics too.

 

[FishFry]

Also....

 

[FishFry]

 

[OVERKILL]

Also....

View attachment 135681View attachment 135682

Who put out a chart with grades that don't exist in J300?

 

[ZeeOSix]

If cold start-up wear was so prevalent and damaging from cars being started cold, one would think that cars that live in the very cold winter climates in the northern US, Canada, Alaska, etc would have noticeably more worn out engines (with similar mileage) than cars living in much warmer climates.

It's been said many times that if the correct/recommended "W" rated oil is used for the vehicle's use climate that adequate lubrication will happen on cold start-up. There was a reason that SAE came up with the "W" rating of motor oils, and it seems to be working so far. One can play the "W" headroom game by using a 0W instead of a 5W if they are afraid of cold start-up wear, just like someone can use xW-30 instead of xW-20 for engine wear protection headroom at operating temperature.

 

[ZeeOSix]

Who put out a chart with grades that don't exist in J300?

Racers who live in a different world of oil viscosity.

 

[CarfriendXX]

If cold start-up wear was so prevalent and damaging from cars being started cold, one would think that cars that live in the very cold winter climates in the northern US, Canada, Alaska, etc would have noticeably more worn out engines (with similar mileage) than cars living in much warmer climates.

It's been said many times that if the correct/recommended "W" rated oil is used for the vehicle's use climate that adequate lubrication will happen on cold start-up. There was a reason that SAE came up with the "W" rating of motor oils, and it seems to be working so far. One can play the "W" headroom game by using a 0W instead of a 5W if they are afraid of cold start-up wear, just like someone can use xW-30 instead of xW-20 for engine wear protection headroom at operating temperature.

And where did they wear out the engines that used to wear out with the thinnest oils? Where are the practical examples? Where? I only see several Toyotas with almost 1 million miles with 0W20, madness how this works! Storage game is also ignored, always this thick oiler fraction.

 

[ZeeOSix]

And where did they wear out the engines that used to wear out with the thinnest oils? Where are the practical examples? Where? I only see several Toyotas with almost 1 million miles with 0W20, madness how this works! Storage game is also ignored, always this thick oiler fraction.

Link to the several Toyotas that used only 0W-20 for a million miles, showing their detailed maintanence records.

Controlled wear studies all basically conclude that below a certain HTHS viscosity (2.5 - 2.6 cP) that wear increases on some engine components. And as the HTHS goes below that threshold the wear rate keeps on increasing. Engine design and materials quality also factor into the wear equation.

Most likey the engines that use xW-20 that last the longest have relatively short OCIs, and are not short trippers and not big fuel diluted engines. Throw those negative factors on top of xW-20 and engine protection can be impacted due to even more viscosity decrease over the OCI. Using even a xW-30 can help mitigate those negatively impacting factors. You ever see any engines wear out faster from using a thicker oil?

Storage game? What?

 

[Retirednow]

They might not have 0W-16 in Coober Pedy.

Or XW-20 or even XW-30.

 

[SubieRubyRoo]

And where did they wear out the engines that used to wear out with the thinnest oils? Where are the practical examples? Where? I only see several Toyotas with almost 1 million miles with 0W20, madness how this works! Storage game is also ignored, always this thick oiler fraction.

You have lots of assumptions here. There also seems to be some convenient amnesia as well. Ahmed has plenty of examples that show there is quite a bit more “inconvenient data” to your fantasy than you want to acknowledge.

 

[CarfriendXX]

Link to the several Toyotas that used only 0W-20 for a million miles, showing their detailed maintanence records.

Controlled wear studies all basically conclude that below a certain HTHS viscosity (2.5 - 2.6 cP) that wear increases on some engine components. And as the HTHS goes below that threshold the wear rate keeps on increasing. Engine design and materials quality also factor into the wear equation.

Most likey the engines that use xW-20 that last the longest have relatively short OCIs, and are not short trippers and not big fuel diluted engines. Throw those negative factors on top of xW-20 and engine protection can be impacted due to even more viscosity decrease over the OCI. Using even a xW-30 can help mitigate those negatively impacting factors. You ever see any engines wear out faster from using a thicker oil?

Storage game? What?

Why should I use thicker oils, more fuel consumption, accept a worse oil volume flow when thinner oils work best? Even in racing, thinner oils are increasingly used, although engines have to last longer without revision than before, funny, isn't it? Gladly fill the thickest oils into the engine to sleep well at night, but they do not speak of "better" in the sense of wear in suitable engines that tolerate thin oils. But that's how it really was, everyone should do what they like.

 

[kschachn]

And where did they wear out the engines that used to wear out with the thinnest oils? Where are the practical examples? Where? I only see several Toyotas with almost 1 million miles with 0W20, madness how this works! Storage game is also ignored, always this thick oiler fraction.

As has already been asked, please link to these Toyotas.

Asking as someone who has put over 450,000 miles on one.

 

[kschachn]

Why should I use thicker oils, more fuel consumption, accept a worse oil volume flow when thinner oils work best? Even in racing, thinner oils are increasingly used, although engines have to last longer without revision than before, funny, isn't it? Gladly fill the thickest oils into the engine to sleep well at night, but they do not speak of "better" in the sense of wear in suitable engines that tolerate thin oils. But that's how it really was, everyone should do what they like.

Volume flow? Here we go again with the alternate physics. The only advantage to thinner oil is slightly increased fuel economy. Nothing else.

 

[CarfriendXX]

You have lots of assumptions here. There also seems to be some convenient amnesia as well. Ahmed has plenty of examples that show there is quite a bit more “inconvenient data” to your fantasy than you want to acknowledge.

I am still waiting for practical examples where engines with thinner oils wear out faster. Everything else is gray theory that questions the practical relevance

 

[OVERKILL]

Why should I use thicker oils, more fuel consumption, accept a worse oil volume flow when thinner oils work best? Even in racing, thinner oils are increasingly used, although engines have to last longer without revision than before, funny, isn't it? Gladly fill the thickest oils into the engine to sleep well at night, but they do not speak of "better" in the sense of wear in suitable engines that tolerate thin oils. But that's how it really was, everyone should do what they like.

How are you getting a worse oil volume flow unless the pump is on the relief?