How does cleaning piston rings reduce oil consumption?

[Faawrenchbndr]

Do you have pictures? I used it for 10 years on a car that didn't consume a drop.

Keep in mind that the driving style of two vehicles can vary greatly. One oil may work well for a car that has a 25 mile commute better than a car that has a 4 mile commute.

It’s often not just about the quality of the oil, but the circumstances the oil operates in

 

[dnewton3]

Stuck rings not only affect oil consumption but compression (which affects power and efficiency).

Many years ago (in my early days of BITOG) I ran an experiment, at the request of Gary Allan, using ARX. I had a Taurus with 3.0L Vulcan engine; it had previously experienced an overheating event and several cylinders were affected by coked rings. After two clean/rinse phases, the compression in my Taurus 3.0L Vulcan went from horrible to factory fresh; around 180psi.

Keeping the ring pack clean is essential to proper operation in many aspects.

 

[dnewton3]

I had to dig up some old details, but here's the data from my compression testing experimenting with ARX.

Here's the background info ... Taurus 3.0L Vulcan engine. The engine overheated because the front passenger-side freeze plug rotted out and there was an immediate release of cooling system pressure and much of the coolant. As you can see from the chart and image, the freeze plug was located between cyls 4 and 5; hence the greatest heat concentration affected those two cylinders. Whereas those two cylinders had almost no coolant, I suspect there was some residual coolant in the back bank, as they were not nearly as badly affected.

A neighbor (elderly woman) was driving it at the time and continued to drive home several miles after the engine lost coolant at a stoplight. (Yes - she should have pulled over and shut it down, but she didn't ... ). So while the engine didn't seize, it did suffer severe heat localization and several of the rings packs coked up hard, because while it "drove fine" on the way home (according to the woman), the oil didn't really get cooked to a carbonized goo until she parked it in the garage and the oil just baked in the ring pack. As you can see from the data, the initial compression readings showed some cylinders with slight sealing problems, and two cylinders with significant problems.

The experiment was done back in 2008, IIRC ...
* Conventional oil base stocks (no syns used).
* Compression checked at the start of each step in the trial.
* Compression rounded to the nearest 5psi increment

- First trial cleaning phase used 2 bottles of ARX in one application (it's noted in the chart as "2app" to indicate two-times the dosage). (1k miles duration)
- Then a rinse phase. (2k miles duration)
- Then a second cleaning phase using only 1 bottle of ARX. (2.5k miles duration)
- Then another rinse phase. (2.5k miles duration)
- Then a final compression check.

As you can see in the chart, without any doubt, the rings were stuck quite badly in cylinders 4 and 5. But after two full cycles of ARX (double dose; rinse; single dose; rinse), the rings were fully liberated. It can't be a bad thing to have full compression with clean engine internals! Rings which can freely float in their lands are always better at controlling the oil film, and maximizing compression for good efficiency.

 

[Hohn]

Products like Valvoline Restore and Protect and/or EC30 are quite handy for a V6/V8 where the pistons are angled - or sideways boxers. Hard to get to plugs as well.
However, an I4/I6 is more ideal for a piston soak with one of several products … and then followed by a good cleaning oil …

Thank you for reminding me how much I miss LC20. Boohoo. That stuff was perfect for what I believe is the "MolaKule Soak"

 

[Mr_Infamous]

It's my understanding that the job of the oil control rings is to scrape most of the oil off the cylinder walls as the piston moves downward. It's also my understanding that on modern engines, there's usually two separate compression "rings" while in the past, some engines used a single key ring shape design. Modern "rings" are in quotes because they aren't actually solid rings, there's a small gap to allow for thermal expansion.


It is the gap in the rings that allow oil to make it into the combustion chamber. Imagine the oil ring is stuck and/or clogged in a way that allows for a 1mm thick strip of the cylinder wall to remain covered in oil. As the piston continues moving down, the lower compression ring hits the puddle, causing it to spread out along the lower ring's bottom edge. Eventually, oil makes it to the lower ring's gap, at which point the upper ring hits the oil puddle and does the same thing.


By the time the piston hits BDC, there's a ring of oil around the bottom edge of the lower compression ring, a thinner ring around the bottom edge of the top ring, and a narrow streak along the cylinder wall corresponding to the upper ring's gap. The streak that makes it past the upper ring gap starts widening as soon as it forms and as the piston starts moving up again from BDC, some of it will be in a position to get pushed up into the combustion chamber by the top ring.

Right? To be clear, I'm bumping this to ask if I'm visualizing it right.

 

[JackWildfeuer]

You only want a small amount of oil to remain on the cylinders bore the part the piston rides up and down inside. If the rings get stuck they allow a thicker film of oil to remain on the walls of the cylinders. So when it is time to combust the fuel in the cylinder any oil on the cylinder wall will get burnt. So the more oil that remains the more that get's burnt over and over and over again.

Pistons used to be larger in almost every way which also meant more drag. As they shrunk the skirts, raised the wrist pins, rasied the rings and lightened the pistons it created a very hostile environment for the piston and rings. They also went to lower tension rings, increased power densities, increased head temp.'s, water temps, added more EGR either directly or with cam phasing they also made the oil returns smaller. Often going from huge slits to tiny little drill holes. Then they went to oils that are thinner with more VII's and pushed out the change interval to lower initial cost of ownership.

So it is not one thing it is a bunch of things that are additive in nature not so much compounding but like that. People like to think of synergy where 1+1=3 as a good thing but synergy can also work against you.

If you look at a run of the mill old non-HP small block Chevy piston or an old Toyota 20R-22RE piston most of them on the bottom grove in the piston which is where the oil ring lives have like 2 inch long drain back slots that you can see day light through 20 feet away in a bad photo. Look at the same area on say a 2AZFE piston and it is maybe 10 small drill holes. I find the famious aution site is a great place to find good photo's if you can not find them any place out.