What if "low tension ring" theory is all wrong?

[userfriendly]

Thanks for sharing. Oxidation is a big deal and should be carefully monitored via a used oil analysis.

If you're using a lower viscosity oil it's important to choose wisely. You want strong oxidation resistance, stout detergent levels and solvency.

VII quantity and type may play a role too. With so many people using dealer bulk 0w20's it should be no surprise that rings will eventually stick at some point. Especially TGMO.

View attachment 305197

Now we’re into “dealer bulk” is inferior to consumer packaging.

 

[fantastic]

Power density and top ring land temperatures.

Emissions and fuel economy (power, too, in some testing) improve as you move the top ring up closer to the top of the piston. Which means modern top rings are moved to much hotter locations.

And that's putting aside the fact that modern engines are making twice as much power per liter as older engines. Back when a 318 was 180hp, it's pretty easy to manage top piston ring temperatures spreading that across 8 pistons.

It must be toasty in those engine areas these days.

Modern oils only got so good because they had to be. An older oil in a modern engine would be a disaster.

Exactly, Oil is an evolution of the times. It evolves when issues are presented.
That being said, like you mentioned, oil has needed to get better & it's important to stick with OEM specified oil at the minimum.

 

[JohnnyJohnson]

Right or wrong the only people they had to sell with their hogwash was CAFE.

 

[BHopkins]

-- Speaking of idling, it causes much less wear than restarts do over time. It's all about keeping those films intact and not having to re-establish them. I might be changing my practice of being so reluctant to allow idling.

Was fuel dilution taken into consideration, when determining that idling "causes much less wear than restarts do over time"? It has always been my understanding that it isn't the constant running of the engine that makes idling a concern, but rather fuel dilution of the motor oil.

 

[buster]

Uh oh, now we are into the "API minimum standards aren't good enough..." discussion

Not when your API oils exceed the IIIH test by 20x.

 

[buster]

Now we’re into “dealer bulk” is inferior to consumer packaging.

Dealer bulk oil is not Mobil 1 Extended Performance, Castrol EDGE Extended Performance, PUP or Valvoline Restore and Protect.

 

[buster]

I would think the off-shelf API EP oils and Valvoline Restore and Protect would keep rings from sticking under OE drains more so then dealer bulk 0w20, some of which have Noack of 13%. Go up further to Euro as well. I'd be curious how many of the ring sticking issues were ran on low cost bulk 0w20's with Noack near 14% and a ton of cheap VM.

 

[BMWTurboDzl]

This was happening to VW/Audi engines running A3/B4, C3 oils (min hths 3.5cP).

 

[BMWTurboDzl]

How does the use of GDI at much higher pressure than port injection, and the use of low tension rings, contribute to the higher levels of deposits? Has a correlation been established?

I'm thankful to be switching to HPL Premium Plus PCMO in the next couple of weeks, knowing Dr Rudnick was a consultant for HPL. May he rest in peace.

Almost a GDI are turbos and they will often run rich to reduce cylinder temps for emissions.

 

[Mechanician]

Yes and no. It's not just low tension rings, it's shorter pistons with shorter crowns, which push the ring pack up toward the chamber, increasing their exposure to heat, while the piston itself is a smaller heatsink. The ring pack itself is often shorter as well, again, providing less space within to sink the heat, so you end up with a lower profile band that's exposed to more heat while simultaneously using thinner lubricants with bases that are more apt to degrade in the presence of that heat and leave deposits.

As I've stated before, low tension rings have been in use for at least 30 years. They are not the reason we are now seeing elevated oil consumption and stuck rings, they are just an easy target for people to blame. There are numerous engines that feature them that do not have these issues, it's a culmination of design choices that ultimately gets you there, most of them made to reduce friction and improve efficiency.

Engines that do exhibit these issues, do not all always have the problem. Even in the same climate, with no special maintenance.
Driving habits, and (I believe) fuel quality are also factors.

 

[userfriendly]

Engines that do exhibit these issues, do not all always have the problem. Even in the same climate, with no special maintenance.
Driving habits, and (I believe) fuel quality are also factors.

Fuel type as well. Engines operating on LPG and CNG may run for thousands of hours without combustion chamber deposits or sticking rings.

 

[userfriendly]

Dealer bulk oil is not Mobil 1 Extended Performance, Castrol EDGE Extended Performance, PUP or Valvoline Restore and Protect.

Good grief! Dealer bulk typically delivered in 1,000L totes or larger always meets or exceeds manufacturer’s specifications.

I’m not simping for validation, just pointing out the facts.
Once again, unless you can prove that one engine oil is superior to another, then sticking to the manufacturer’s approvals is the best option.

In other words, I’m not interested in playing Celebrity Engine Oil.

 

[fdcg27]

AI Cliff's Notes huh?
Sounds pretty compelling.
Guess you and the AI missed the part about engines lasting longer in service using the recommended grade oil than was typically the case back in the day of thicker grades, which is the reality.

 

[Hohn]

Was fuel dilution taken into consideration, when determining that idling "causes much less wear than restarts do over time"? It has always been my understanding that it isn't the constant running of the engine that makes idling a concern, but rather fuel dilution of the motor oil.

Yes, but the dilution discussion was in the context of very thick oils (hths:5) with gobs of viscosity margin.

 

[ka9mnx]

I guess BMW had it right when my '87 325, with low tension piston rings, called for xw-40.

 

[Azimuth]

-- Thicker oils like 20w-50s lower wear rate as much if not more at low load than they do at high load.

Does the winter rating play a role here when talking about thicker? I.e. would a hypothetical 10w-50 do the same in this application?

 

[Japanese]

Thanks for the read! Very interesting info.

It reminded me to tell next time the guys that always run top tier fuel that their intake valves get dirty not because the low tier fuel burns dirtier than top tier, but because EGR gases pass trough (and there is certain amount of oil in them) them regardless of port or direct injection.
I'll mention that in the top tier fuel threads later this week.

German cars (mostly turbo) that run thick Euro oil get stuck piston rings and burn oil regardless of the better quality oil. What about that?

 

[burbguy82]

It's unfortunate that we guinea pig consumers are the ones who pay for these questionable improvements. Engineering isn't cheap.

One wonders if the end user recoups sufficient individual fuel savings to compensate - including ongoing maintenance and repair costs.

100% agree. Well said.

I feel as the premise of this thread points to an overwhelming contradiction/incompatibility of things....., requirements, lube, fuel, design, driving style etc. The sum of which is not good for the consumer, and by in large, counter productive to the "efficiency" goals.

 

[Jetronic]

Uh oh, now we are into the "API minimum standards aren't good enough..." discussion

Is that even a discussion?

I'd say acea minimum standards aren't good enough either.....

 

[Jetronic]

Was fuel dilution taken into consideration, when determining that idling "causes much less wear than restarts do over time"? It has always been my understanding that it isn't the constant running of the engine that makes idling a concern, but rather fuel dilution of the motor oil.

I would love to see how much fuel dilution is going on in an up to temp idling engine. I can see it being an issue on a cold engine, or on an engine with less than perfect injectors