Low Tension Piston Rings

[Mainia]

I know we have been talking about low tension piston rings and here is someone did some testing that "may" show a slow slide to lower and lower tension through their model years or engine series of some Toyota engines. While Overkill may have a valid point, when some started using them, I personally think the 30 year mark can't be set in stone as a "set" year they all did the switch. He has posted it here and before on other threads where low tension piston rings have been brought up. I personally feel just saying a set 30 years starting point is a "sweeping generality" that doesn't have a direct stated 30 years start date on every manufacture. The video poster stated right off the bat he doesn't have the proper scientific equipment, and this is just a rudimentary test.

 

[AZjeff]

You'd better put some narrative with the video or it will disappear. Rules.

 

[OVERKILL]

Unless they mention that we've been using low tension rings for more than 30 years, it's likely click-bait.

 

[JavierH19]

You gotta add some text to your post or mods will remove it if it's just a video/link no matter if you're new or not.

 

[Mainia]

Unless they mention that we've been using low tension rings for more than 30 years, it's likely click-bait.

I guess not Toyota, did you even watch it? Or is 30 years a sweeping generality with some outliers ?

 

[OVERKILL]

I guess not Toyota, did you even watch it? Or is 30 years a sweeping generality with some outliers ?

Toyota has also screwed up the oil control return holes (as did GM with Saturn). 30+ years we've been using low tension rings. Some implementations have been problematic, often due to other dumb decisions made by the OEM unrelated to ring tension. My point is that low tension rings are not some recent and untested harbinger of engine failure that people would have you believe. We have decades of experience with them. The reason most people don't know this is because most of the experience has been positive.

And no, I'm not clicking on a video that's likely monetized, when it's board policy for the OP to provide a summary of said video, otherwise the thread is likely to get disappeared by the moderators. @dnewton3

 

[4WD]

My sister just gave away an old Saturn running perfectly and bought a new Buick Enclave … The motor only saw M1

 

[Mainia]

Toyota has also screwed up the oil control return holes (as did GM with Saturn). 30+ years we've been using low tension rings. Some implementations have been problematic, often due to other dumb decisions made by the OEM unrelated to ring tension. My point is that low tension rings are not some recent and untested harbinger of engine failure that people would have you believe. We have decades of experience with them. The reason most people don't know this is because most of the experience has been positive.

And no, I'm not clicking on a video that's likely monetized, when it's board policy for the OP to provide a summary of said video, otherwise the thread is likely to get disappeared by the moderators. @dnewton3

That explains your sweeping generality comment.

 

[Mainia]

You'd better put some narrative with the video or it will disappear. Rules.

Too late it dropped my edit time

 

[Mainia]

Too late it dropped my edit time, they can smoke the post if they want. I would have put some dumb comment on the video’s header anyway with words to follow some rule set. Those words would be moot, so smoke the post.

 

[Rand]

Too late it dropped my edit time, they can smoke the post if they want. I would have put some dumb comment on the video’s header anyway with words to follow some rule set. Those words would be moot, so smoke the post.

Talking in the 3rd person or just accidently quoting yourself?

 

[brages]

You'd better put some narrative with the video or it will disappear. Rules.

I don't agree with all the forum rules, but I sure do agree with that one.

 

[OVERKILL]

While Overkill may have a valid point, when some started using them, I personally think the 30 year mark can't be set in stone as a "set" year they all did the switch. He has posted it here and before on other threads where low tension piston rings have been brought up. I personally feel just saying a set 30 years starting point is a "sweeping generality" that doesn't have a direct stated 30 years start date on every manufacture.

The point being, broadly, that they haven't been problematic for the vast majority of applications in which they were fitted over that 30 year period, which underscores it being an implementation problem not a technology problem.

We have more than just low tension rings going on now. We have super short pistons with the rings pushed up toward the crown to minimize swept ring area, we have ultra thin oils that are more prone to coking, and these oils are getting into a ring pack that is much hotter, due to it being pushed up, which drives up the propensity to develop deposits.

Low tension rings entered the picture in the 80's as part of the pursuit of improved fuel economy and reduced bore wear. They became more common through the 90's as the focus on fuel economy increased. Ford's Windsor engines got them in the late 80's/early 90's, the modern HEMI has them (as did the Modular and later Coyote engines). None of these engine families is known for considerable oil consumption, but none of them spec 0W-8. The 5.7L HEMI does have the rings pushed up further toward the crown:

When compared to a 4.6L Modular:

But there's still some decent spacing on the ring pack, and the oil control ring area is relatively wide.

Here are some Toyota A25A pistons:

Now, these are tiny pistons, but notice the ring pack is much tighter (but a decent crown gap) with the oil control rings being TINY and packed close to the 2nd compression ring, unlike the HEMI or Modular. And of course they are caked up.

That tight, small oil control ring design, in a short piston, with a short, hot running top, is just asking for coking, which is exactly what we see.

 

[Mainia]

The point being, broadly, that they haven't been problematic for the vast majority of applications in which they were fitted over that 30 year period, which underscores it being an implementation problem not a technology problem.

We have more than just low tension rings going on now. We have super short pistons with the rings pushed up toward the crown to minimize swept ring area, we have ultra thin oils that are more prone to coking, and these oils are getting into a ring pack that is much hotter, due to it being pushed up, which drives up the propensity to develop deposits.

Low tension rings entered the picture in the 80's as part of the pursuit of improved fuel economy and reduced bore wear. They became more common through the 90's as the focus on fuel economy increased. Ford's Windsor engines got them in the late 80's/early 90's, the modern HEMI has them (as did the Modular and later Coyote engines). None of these engine families is known for considerable oil consumption, but none of them spec 0W-8. The 5.7L HEMI does have the rings pushed up further toward the crown:
View attachment 272280

When compared to a 4.6L Modular:
View attachment 272281
But there's still some decent spacing on the ring pack, and the oil control ring area is relatively wide.

Here are some Toyota A25A pistons:
View attachment 272282
View attachment 272283
View attachment 272284

Now, these are tiny pistons, but notice the ring pack is much tighter (but a decent crown gap) with the oil control rings being TINY and packed close to the 2nd compression ring, unlike the HEMI or Modular. And of course they are caked up.

That tight, small oil control ring design, in a short piston, with a short, hot running top, is just asking for coking, which is exactly what we see.

Excellent comment, and highly pertains to my Hyundai pistons and rings. I notice this on all the pistons I have seen on late model Hyundai pistons. They are very very short, with a high top ring, and I saw a ton of rock wear on them with low miles. That is why I always warm up my car even in the summer. I can get 17 to 23 psi boost at 1,700 rpm depending on water temp.

I had massive fuel dilution as high as 1.5 qts in a 3,000 mile oil OCI. I have none in the summer ( <- use to have 1/2 qt++) and now very slight in the winter. This with high end oils Amsoil SS, Mobil1 Extended, Mobil1 ESP 5w-30 for 2 years use. It took Redline Performance Euro 5w30 to break that massive dilution. I even PM ed Moleakule when on my first running of it mid to end time frame my dilution was gone. He was somewhat perplexed and thought the ester could of made the rings seal better, but with time my hypothesis is I had jammed top or secondary rings where most Hyundai's that aren't highly beat on get jammed oil rings. I did/do keep them free now that I don't use Redline because they priced me out of their market. I am at this point running VRP 5w-30 during Minnesota winters as my car is a short tripper daily. I have had great results with a smoother running motor and a better idle after running 4) 3,000 miles of VRP. Nothing else has changed on my car. I can notice this because of hardened motor mounts and just listen to the car. The car just runs better after the 4) OCI of VRP. In summer I will be going back to Motul 8100 Clean Gen 2 with HPL EC40 every other OCI and then back to VRP in the winter.

 

[dkryan]

OVERKILL,

Thanks for those Toyota A25 piston photos above.

Here’s hoping that HPL Premium Plus PCMO is preventing the above scenario in spite of my 10k mile OCIs in my 2.5L Highlander hybrid!

 

[BMWTurboDzl]

I know we have been talking about low tension piston rings and here is someone did some testing that "may" show a slow slide to lower and lower tension through their model years or engine series of some Toyota engines. While Overkill may have a valid point, when some started using them, I personally think the 30 year mark can't be set in stone as a "set" year they all did the switch. He has posted it here and before on other threads where low tension piston rings have been brought up. I personally feel just saying a set 30 years starting point is a "sweeping generality" that doesn't have a direct stated 30 years start date on every manufacture. The video poster stated right off the bat he doesn't have the proper scientific equipment, and this is just a rudimentary test.

Clifton notes. Toyota has used lower and lower tension rings over various engine interations and with the most recent powerplant the warnings of excessive oil consumption have appeared. The YT claim is that the rings combined with the requred finer cross hatch are causing the excessive consumption and how inexcusable it is for Toyota to issue a warning about 1l/1k km consumption on an engine with a 4 liter sump.

He then goes on to say how these engines are actually dirtier from the consumption but automakers get away with it because the emissions testing is conducted on a "new" engine.

He set up and interesting contraption to measure the tension of the rings. Measure the rings for there Toyota engines from various era's.

 

[Hohn]

Toyota has also screwed up the oil control return holes (as did GM with Saturn). 30+ years we've been using low tension rings. Some implementations have been problematic, often due to other dumb decisions made by the OEM unrelated to ring tension. My point is that low tension rings are not some recent and untested harbinger of engine failure that people would have you believe. We have decades of experience with them. The reason most people don't know this is because most of the experience has been positive.

And no, I'm not clicking on a video that's likely monetized, when it's board policy for the OP to provide a summary of said video, otherwise the thread is likely to get disappeared by the moderators. @dnewton3

Not only have we had low tension rings awhile, but often the rings got thinner to enable that lower tension to produce similar contact pressure.