Thicker oil equals more timing chain wear

RDY4WAR said:
Comparing base oils of similar polarity, the solvent power decreases as viscosity increases.
Click to expand...
Keep in mind that when oil is at 100C (about what most oil runs at operating temperature), what's the viscosity difference between 20, 30 and 40? It's like 5 cSt between 20 and 40. Is there any technical information or studies you can link that shows if all things are equal that a 5 cSt difference in viscosity is going to make a big difference in the cleaning ability of oil?

RDY4WAR said:
Solvent power is interrelated with lubricity and additive response. The Hildebrand solubility theory tells us that anytime the average molecular volume increases (higher viscosity), the aniline point is increased and thus solvent power is decreased.

Solvent power and lubricity are interrelated as both require the presence of polar molecules. (Lubricity requires both polar and non-polar molecules to be present simultaneously) Lubricity, in the terms we're talking about, refers to the oil's cohesion to metal surfaces and slipperiness of the film on that surface. Therefore, lower viscosity base oils (of similar polarity) have greater solvent power for dissolving sludge and grime, while also having greater lubricity and thus surface cohesion, assuming the whole oil formula accounts for it.
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Got some technical links ... or is this just a theory? With the same exact additive package, where's the info that says that a thinner viscosity oil will dissolve sludge and grime, and clean better than a thicker viscosity?
 
metroplex said:
The European GTDI engines generally run thicker oils like xW-40 or xW-50 synthetics and their tail pipes are black like my coffee. The carbon is from fuel soot, nothing to do with the engine oil.

The oil that gets on the top of the valves is mainly from crankcase blow by and the turbos. People are slapping cheap catch cans like the JLT, trying to catch it all but all they are doing is slowing down the PCV valve flow and condensing it into fluid, so they can show off the gunk and proudly proclaim they are saving their engines. Meanwhile the OEM designed the PCV system to be as short as possible so the hot blowby gases can be combusted without being condensed into liquids. The single catch cans neglect the blowby from the cleanside part of the PCV system, as well as the oil that comes out of the turbo's that pool in the intercooler and get sucked back into the intake manifold. The more complex Tracy Lewis systems are better as it is a comprehensive system, but probably won't catch the oil that comes out of the turbos.
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You can not beat Car manufacturer engineering. Aftermarket snake oil.
 
RDY4WAR said:
Comparing base oils of similar polarity, the solvent power decreases as viscosity increases. Solvent power is interrelated with lubricity and additive response. The Hildebrand solubility theory tells us that anytime the average molecular volume increases (higher viscosity), the aniline point is increased and thus solvent power is decreased.

Solvent power and lubricity are interrelated as both require the presence of polar molecules. (Lubricity requires both polar and non-polar molecules to be present simultaneously) Lubricity, in the terms we're talking about, refers to the oil's cohesion to metal surfaces and slipperiness of the film on that surface. Therefore, lower viscosity base oils (of similar polarity) have greater solvent power for dissolving sludge and grime, while also having greater lubricity and thus surface cohesion, assuming the whole oil formula accounts for it. This also makes it better in terms of seal conditioning and dispersancy.

Looking at PAO base oils of different viscosity, just to give an idea...

Aniline point of PAO 2 = ~100°C
Aniline point of PAO 40 = ~160°C
Click to expand...

And POE has aniline points down to negative temperatures, AN are somwhere in between PAO and POE.

In other words, base oil selection matters more than viscosity

https://www.stle.org/images/pdf/STL...halenes for High Temperature Applications.pdf

https://www.exxonmobilchemical.com/en/products/synthetic-base-stocks/esters
 
ZeeOSix said:
Keep in mind that when oil is at 100C (about what most oil runs at operating temperature), what's the viscosity difference between 20, 30 and 40? It's like 5 cSt between 20 and 40. Is there any technical information or studies you can link that shows if all things are equal that a 5 cSt difference in viscosity is going to make a big difference in the cleaning ability of oil?


Got some technical links ... or is this just a theory? With the same exact additive package, where's the info that says that a thinner viscosity oil will dissolve sludge and grime, and clean better than a thicker viscosity?
Click to expand...

https://www.stle.org/images/pdf/STL...lubility and Lubricity_tlt article_July09.pdf
 
RDY4WAR said:
https://www.stle.org/images/pdf/STL...lubility and Lubricity_tlt article_July09.pdf
Click to expand...

The article talks more about the effect of lubricity due to solvency than it does about cleaning any existing sludge. In fact, there really isn't any mention that lower viscosity oil will clean sludge and keep and engine cleaner due to just the effect of viscosity. KV100 is KV100, regardless of the base oil or the additives.

Throughout the article, it mentioins a loss in viscosity index with higher solvency. Viscosity index is not the same thing as the viscosity (ie, KV100). It never mentions any kind of correlation between solvency and the actual viscosity or viscosity rating of the oil. I think you might be trying to read between the lines and somehow conclude that "lower viscosity oil will clean sludge and grime better". I see no evidence in that article that's true. They never once addressed any kind of relationship between cleaning power and oil viscosity. That was the point that started this discussion.

Quotes from the article:

Improvement in solvency comes at a price of a loss in viscosity index.

Improvements in solvency and lubricity come at a price of deteriorating viscosity index.

Improvements in solvency and lubricity come at a price of downgrading stability.

With base oils, solvent power is chiefly determined by polarity of oil molecules.

What does lubricity have to do with all that? Solvent power and lubricity are interrelated properties.

However, solvent power alone does not guarantee good
lubricity. Lubricity requires that polar and non-polar mol-
ecules be present simultaneously. Since metal surfaces are
highly polar, polar oil molecules dissolved in non-polar am-
bient tend to adsorb to the metal surface, forming a protec-
tive surface film. Strength of the film and solvent power are
linked to the same cohesion parameters.
Group I base oils have sufficiently high content of polar
species (heterocycles, alkylated aromatics) and demonstrate
superior lubricity as compared to Group II-IV base oils. Cor-
respondingly, Group II-IV base oils will benefit the greatest
in terms of lubricity from using boundary lubricity additives,
also referred to as friction modifiers among tribologists.

The last quote mentions nothing about the cleaning abilities on existing sludge and grime, only lubricity performance related to solvency.
 
2EHA said:
View attachment 40374
View attachment 40375

yes, oil pressure operates a piston which pushes on the guide rail, or sometimes a dedicated pad
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This could why with thicker grade oil I dont hear chain at start up. Because of this theory. I have a 2014 mercedes benz cls 550 and it calls for 0w40. At start up i hear chatter or so i think. It could be direct injection injectors being chattery too. I switched to 15w50 and it runs great on it and no noise at start up. Just a thought since oil pressure puts more pressure on guides keeping chain tigher yes? Idk but these engines have check valves too that are bad design and all oil up top goes to the bottom. The thicker oil seems to also help with dry starts.
 
ZeeOSix said:
Thicker oil would result in more oil pressure from the pump. But keep in mind that all oil is pretty thick when cold, so during a cold start and the warm-up phase, there is more oil pressure going on in every engine.
Click to expand...
This is why warming up the engine while driving and driving it easy at first is imperative for chain wear
 
Flyingdutchman said:
Today i read something interesting in a dutch automotive magazine that is handed out to a lot of repair shops, they also discuss a lot of common engine problems and discuss and clarify things with the help of experts.

This topic was about sticking to oem oil spec or going to a different spec/weihgt. So one of our favorite subjects :)

One lubricant expert stated that you should stick to oem wheight/spec (which i agree with) because with switching to a thicker weight the oil pressure will increase which in terms will also put more force/pressure on the timing chain tensioner because those are motor oil hydraulicly actuated.

I thought this was an interesting point which probably has some truth to it: thicker oil= less internal leakage/flow = higher pressure = more force on tensioner = more tensioning/stretching force on the chainlinks and sprockets itself.

Especially when the oil is cold, and by using thicker cold grades then oem spec.


Some engines are known for having poor timingchain quality, other have no problems at all.
I guess that maybe the engines that are known for poor quality might wear a little faster, but i dont think it will cause a lot of trouble on the cars that dont have any problems with it generaly.
Click to expand...
Beard strokers anonymous strokes again.
 
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