Cleaning the oil ring within the engine

[DamboDD]

My Clio 172 ph2 have a issue which pretty much annoy me, it can make a liter of oil disappear in the mirror in 500 km fast road trip ( i noticed it mostly happens when engine high revs with closed throttle i.e vacuum). but can go 1000 calm km and take only 100 cc of oil or less.
some details: 192k-km, timing spot on, new valve oil stem seals(OEM)(w/o opening the engine), fuel additives tried like bg-44k, engine flushed once, compression 185-190 on all four, oil separator genuine new seal, injectors cleaned, 3rd piston is wet, leak down test shows 15-18% leak in 1 minute wait IIRC, it was in the low part of the green range on gauge.
It pretty much feels like providing good power unless it runs in hot environment with high rpms (i guess the oil is too hot so it thinner and flooding the piston) then there is significant power drop. before the car got to me it was maintained like regular car and got oil changes every 15k-20k KM with second grade oils. never overheated, no apparent oil leaks. ohh and of course, above 5k rpm, it leaves a beautiful blue screen of smoke behind it if i hit the throttle after a few downshifts and engine braking.

I left to think that the only issue is with a stuck oil piston ring. which is the annoying part because opening the engine or replacing it for this feels like a waste to me.
unless its a broken piston ring/ piston, i would like to try cleaning the piston rings within the engine and restore the engine to his brighter days, which i honestly believes possible.

After watching youtube videos and did some reading about carbon build up and burned oil build up and carbon dissolving detergents, it seems like it is possible but mostly not fully tested and not got real proof for me. at least not on a F4R engine.
People tried White viniger with good results on rust, combining 50:50 acetone with ATF or used plane turpentine. but most of them did it, with limited success on parts of of the engine that are not installed. some tried engine flush with no good results and some showed reduced oil consumption, but i don't know if the engines later used for high performance or just go to the mall. and none of them did follow up on this issue once it got solved, allegedly.
The one that got my attention was someone with low compression (100) whom tried filling the cylinder with something like carbon build up cleaning solvent (sea foam-not available to me), let it soaked for 2 days while refilling every 8 or so hours, then applied penetrating oil for two more days and cleaned it all with brake cleaner. this made his compression to go back to 180. (of course after changing engine oil and filter).
I've seen some amazing results of cleaned pistons within engines, carbon build up wise, but not mentioning freeing piston rings.

What do you think about it? someone tried it on a F4R with success and long term experience after the clean?
will this engine be OK with the harsh cleaning solvents like injector cleaner or similar inside of it? with brake or crab cleaner? is there anything i should avoid doing this? anything to pay attention to?

I'm currently planing on doing this and want to try to clean and unstick the piston rings with hope that that is the problem and that it is curable.
Will let you know if any updates.

my plan now is to try use baroscope for footage and mointoring and to pour into the cylinders injector cleaner on a mildly hot engine, and let it soaked for a few days. spary some penetrating oil and brake cleaner after a few more days. to use a cloth to soak everything out, and wipe whats possible on the pistons. might add another attemp to flush the engine and replace engine oil 2 consecutive times.
I'm worried about the crank bearings, but i might spray some oil on the crank from the oil drain plug if i manage to access it thru the plastic cover there.

any other way to fix this while keeping the engine closed will be appreciated.

thanks guys.

 

[R3k1355]

You won't see an oil control ring with a boroscope, if there's alot of carbon on the piston you'll see that but it won't be causing your problems.

IMO you soak the effected cylinder in WD40 for a week or so to soften the carbon deposits on the stuck ring.
Then start putting ATF down the bores, ATF has some decent detergents that will break up and slowly remove the carbon, it won't be a quick process.

You might not get it clean, but you might get it clean enough to do it's job.

 

[R3k1355]

Alternatively, water/meth injection might be an option?

 

[DamboDD]

Yeah, i mean that the baroscope will be used for seeing the piston and monitor the cleaning process.
I thought about WD40 but because its water based I’m not sure how it will deal with carbon deposits and burned oil, and lots of em.
If I’ll use it too, should i combine (separately) all of them (i.e WD40, ATF, injector cleaner and brake cleaner) or choose only a few?
My engine runs relatively clean if you put aside the burned oil deposits. Very minor carbon build up.

i tought about pouring water to fuel tank and let the steam do its magic but I don’t think it will fix the stuck ring. What do you mean by injecting water and what is meth?

 

[NorthloopCup]

I’d suggest you’re suffering from a potential cracked ring land on the piston. It’s a common issue on the f4r when they’re drinking oil.

 

[R3k1355]

I thought about WD40 but because its water based I’m not sure how it will deal with carbon deposits and burned oil, and lots of em.

WD-40 isn't water based, it's oil.

I’d suggest you’re suffering from a potential cracked ring land on the piston. It’s a common issue on the f4r when they’re drinking oil.

This is your most likely problem.