Cylinder Solvent Flush Candidate?

[jliltd]

I started a condition inspection on my RV-8 with IO-360. When I removed the bottom spark plug from #3 I had about a teaspoon full oil come out, and appeared to be cut by a bit of avgas so it was more "fluidish". Prior to the plug removal I did a compression check on #3 using the upper spark plug hole for the compression tester. It came in at 78/80. This was a test with engine hot after a little more than an hour flight.

This engine has 415 hrs TTSNEW and170 hours on a Barrett major with 170 hours on brand new Superior through-hardened steel cylinders.

Later today I will re-run a cold compression check on the cylinder.

I got my borescope camera and looked inside and found evidence of oil. In fact there is a a wet creek of it along the bottom of the cylinder wall heading for the bottom spark plug hole. The drain path that leaked out of the hole when I removed the spark plug. The edge of the piston is shiny wet with oil. See photos. Ignore the date stamp as my camera wasn't set.

I see mention of the cylinder solvent rinse process that can help loosen up stuck rings and get the oil control ring back to working properly. Would this cylinder be a good candidate for the solvent flush process as presented by Aircraft Specialties Lubricants and SAVVY?

 

[BH1166]

What is your oil needs between oil changes and hours between change and add oil? Is it consuming/burning, or blowing by? Catch can empty, more than usual oil on belly, or do you push blow by back into engine? If consumption flush may help. If blow by less likely.

 

[cubdriver]

I had a similar situation with good compression but oil leakage fouling plugs and burning excessive amounts of oil. In the end, I found that there was a small crack leaking oil into the combusion chamber fouling one of the plugs severely. I replaced that cylinder. I'd do the flush but keep in mind you could have a crack.

 

[jliltd]

I did a cold compression just now on the subject cylinder and it held steady at 76/80. But there was small amount of air heard from the dipstick filler tube. No noise from exhaust. Intake was indeterminate with the snorkel and everything but it didn't seem to be making noise. I would call the valves good and the rings the culprit. Would this warrant the solvent flush process or am I just pis@#$g up a rope?

 

[blaplante]

so, if the noise is in the crankcase, the leakage is past the rings. So anything that might help the rings is worth trying.
The solvent flush might help. If it was mine, I'd try it.

Curious about the remark above where a crack in the cylinder was causing oil to get into the cylinder. Huh. Where was the crack? There's no pressurized oil in a cylinder so I'm having a hard time understanding how that could work.

 

[BH1166]

I did a cold compression just now on the subject cylinder and it held steady at 76/80. But there was small amount of air heard from the dipstick filler tube. No noise from exhaust. Intake was indeterminate with the snorkel and everything but it didn't seem to be making noise. I would call the valves good and the rings the culprit. Would this warrant the solvent flush process or am I just pis@#$g up a rope?

Ive got same symptoms, about same pressure cold check #3. Im currently running seafoam 1oz each qt in sump hoping it cleans up some stuff in the lands. Mine is mostly all blow by, not burning it. Seems to consume 1 qt per 10 hours. Ive held off on flush since its main purpose is to clean oil control ring passages.

 

[MED]

Ive got same symptoms, about same pressure cold check #3. Im currently running seafoam 1oz each qt in sump hoping it cleans up some stuff in the lands. Mine is mostly all blow by, not burning it. Seems to consume 1 qt per 10 hours. Ive held off on flush since its main purpose is to clean oil control ring passages.

I quart in 10 hours sounds like pretty normal oil usage to me.

 

[BH1166]

I quart in 10 hours sounds like pretty normal oil usage to me.

Not horrible I agree…..but up from previous 6 months, catch can and belly shows it. The breeze coming out filler neck is surprising with 76/80 !

 

[blaplante]

I'm going to try some Liqui Moly Engine Flush in my car at next oil change. Oil consumption is creeping up (189,000 mi). Plan is to put in just prior to oil dump, run gently for a short while, then dump it. Time will tell, but some folks have had luck with it on Volvo and Audi engines. FWIW! But for an aircraft engine the solvent flush (as described by Mike Busch) would be my go-to.

 

[rv8ch]

I'm going to try some Liqui Moly Engine Flush in my car at next oil change.

This video addresses engine oil additives, and spoiler alert, they are not recommended.

The solvent ring flush is very different from the engine oil additives discussion.

 

[[email protected]]

This video addresses engine oil additives, and spoiler alert, they are not recommended.

The solvent ring flush is very different from the engine oil additives discussion.

It's not going to cost you much to do the ring flush.
I have an 560 hour 0-360 with SDS fuel and air running Costco premium channel chrome cylinders 1-6 oil consumption. Did ring flush and went from 1-5.5 to 1-6. Blackish Phillips 20/50 XC oil by 10 hours. always change at 25.
Got a weird vibration in the "prop" and after much looking, trying, asking, and hand wringing, I pulled the motor cause people thought the front main bearing was toast.
BUT I found #4 cylinder had a top ring broken. It is tore apart on my engine bench now.
I had a second engine in my hangar.
Hope you do not experience the problem.
Oh by the way my compressions were 80/78 with no noise anywhere BUT I had oil in the cylinders like you.
AND the vibration was a wheel pant that had two slightly loose rivets.
My luck varies FIXIT

 

[blaplante]

This video addresses engine oil additives, and spoiler alert, they are not recommended.

The solvent ring flush is very different from the engine oil additives discussion.

And --- oil additives (put in and LEFT IN) is a different discussion than using a 'flush' treatment. I was not advocating for adding some additive to the oil (and leaving it in) in order to possibly clean/unstick rings. My opinion is anything in sufficient concentration or sufficient 'eat stuff' characteristics is probably not a great lubricant. Personally I won't put snake oil into my engine and then go subject it to high load (as in take off power).

 

[RNB]

I started a condition inspection on my RV-8 with IO-360. When I removed the bottom spark plug from #3 I had about a teaspoon full oil come out, and appeared to be cut by a bit of avgas so it was more "fluidish". Prior to the plug removal I did a compression check on #3 using the upper spark plug hole for the compression tester. It came in at 78/80. This was a test with engine hot after a little more than an hour flight.

This engine has 415 hrs TTSNEW and170 hours on a Barrett major with 170 hours on brand new Superior through-hardened steel cylinders.

Later today I will re-run a cold compression check on the cylinder.

I got my borescope camera and looked inside and found evidence of oil. In fact there is a a wet creek of it along the bottom of the cylinder wall heading for the bottom spark plug hole. The drain path that leaked out of the hole when I removed the spark plug. The edge of the piston is shiny wet with oil. See photos. Ignore the date stamp as my camera wasn't set.

I see mention of the cylinder solvent rinse process that can help loosen up stuck rings and get the oil control ring back to working properly. Would this cylinder be a good candidate for the solvent flush process as presented by Aircraft Specialties Lubricants and SAVVY?

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I am curious what scope this is? Would you buy it again? I was shopping yesterday.

 

[DaveO]

I am going to throw a new thought. What I see in the picture is oil flowing from the top down to the bottom of the cylinder. The question I would ask why is oil flowing from the top down into the cylinder. I do not think that rings will cause that to happen. It seems that the oil which is being added from the push rod tubes flowing into the cylinder is where I would start looking. The bottom rings do not sit constantly in oil, ie...that would allow oil to flow into the cylinder. Yet even then, when the engine is not working no oil is flowing into the rocker arms. A crack seems possible, somewhere. Well, my thoughts are only worth a puff of wind.