Io360 a1a cylinder blow by. Replace?

[Ragsf15e]

9 minutes ago, Teddyhherrera said:

Man, if my only problem is that I'm not running it lean enough then I'm happy to be wrong!

I guess what I’m saying is blowby (some) is normal. We all have some.  Even a new engine will have some.  The tolerances are much different than modern liquid cooled car engines, so expect a little blowby.  If suddenly you’re losing a qt of oil every 2-3 hours and the belly under the pilot side is super oily, then maybe you’ve got a blowby problem.

What was your oil usage again?

[Shadrach]

12 hours ago, Teddyhherrera said:

Man, if my only problem is that I'm not running it lean enough then I'm happy to be wrong!

Mixture has nothing to do with an oil wetted plug. Blowby usually accompanies diminished compressions, increased oil consumption and oil on the belly after being blown out the breather. 

Many things might contribute to an oily plug. The plug/harness could have an issue causing it not to fire at cruise power. Try a mag check in cruise the next time you fly.  The rocker box drain could be slow, causing oil to pool in the rocker box and leak into the cylinder through that intake valve guided. 

Blowby on a cylinder consistently giving a compression reading in the high 7X/80 range seems unlikely.

[MB65E]

Change the oil early a few times. I never let mine go 50hrs.

Tempest 37BY plugs are great. I think they were developed for the same issue. 
 

If able run it at 25° per the data plate and lean often.
 

Don’t change the Cylinder. 
-Matt

 

[PT20J]

Blow by is combustion gasses "blowing by" leaky compression rings and into the crankcase. It can pressurize the case blowing oil out the breather onto the belly and in severe cases the hot gasses can burn the piston. It sounds more like you are getting oil in the combustion chamber. This can come from worn valve guides or it may be getting past the rings. Oil gets splashed onto the cylinders when the piston is at the top which is good because it lubricates the cylinder/ring interface. The rings ride over the cylinder on a thin layer of oil -- otherwise rings and cylinder would wear out quickly. The oil control ring at the bottom of the piston scrapes off most of the oil leaving just enough. If this ring isn't doing it's job, more oil gets into the cylinders increasing consumption and, if enough gets into the combustion chamber, plug fouling. Cylinders with this condition can show good compression during a leak down test because the excess oil seals the area between the rings and the cylinder walls improving the seal.

[Teddyhherrera]

31 minutes ago, Ragsf15e said:

I guess what I’m saying is blowby (some) is normal. We all have some.  Even a new engine will have some.  The tolerances are much different than modern liquid cooled car engines, so expect a little blowby.  If suddenly you’re losing a qt of oil every 2-3 hours and the belly under the pilot side is super oily, then maybe you’ve got a blowby problem.

What was your oil usage again?

1 every 6-8 hours. It spits down to 6 qts immediately and stays there for about 6-8 hours

[PT20J]

3 minutes ago, MB65E said:

Change the oil early a few times. I never let mine go 50hrs.

Tempest 37BY plugs are great. I think they were developed for the same issue. 
 

If able run it at 25° per the data plate and lean often.
 

Don’t change the Cylinder. 
-Matt

 

The extended electrode BY plugs were developed by Champion to alleviate lead fouling problems most notably in the O-235-L2C in the C-152. They are approved for some but not all engines so you have to check. As you noted, Tempest also makes them. I use them in my IO-360 and like them a lot. They have all the operational advantages of fine wires except longevity, so you have to gap them occasionally and replace them every 500 hours or so, but at least they are not crazy expensive like the fine wires.

[Teddyhherrera]

12 minutes ago, MB65E said:

Change the oil early a few times. I never let mine go 50hrs.

Tempest 37BY plugs are great. I think they were developed for the same issue. 
 

If able run it at 25° per the data plate and lean often.
 

Don’t change the Cylinder. 
-Matt

 

I change it around 35-40. I intend to lean it alot more now. I tell you, today was a day and night difference. Especially since I usually cruise at 6500+

[PT20J]

2 minutes ago, Teddyhherrera said:

1 every 6-8 hours. It spits down to 6 qts immediately and stays there for about 6-8 hours

A quart every 6-8 hours is not atypical for a mid-time Lycoming. A lot of people run 6 quarts max and add when it gets down to 5. Some find that oil above 6 quarts gets blown out the breather. Another trick it to change oil type. I found that my oil consumption decreased when I switched from Aeroshell 100 to Phillips X/C 20W50. I've talked to others that had the opposite experience.

[Teddyhherrera]

16 minutes ago, PT20J said:

Blow by is combustion gasses "blowing by" leaky compression rings and into the crankcase. It can pressurize the case blowing oil out the breather onto the belly and in severe cases the hot gasses can burn the piston. It sounds more like you are getting oil in the combustion chamber. This can come from worn valve guides or it may be getting past the rings. Oil gets splashed onto the cylinders when the piston is at the top which is good because it lubricates the cylinder/ring interface. The rings ride over the cylinder on a thin layer of oil -- otherwise rings and cylinder would wear out quickly. The oil control ring at the bottom of the piston scrapes off most of the oil leaving just enough. If this ring isn't doing it's job, more oil gets into the cylinders increasing consumption and, if enough gets into the combustion chamber, plug fouling. Cylinders with this condition can show good compression during a leak down test because the excess oil seals the area between the rings and the cylinder walls improving the seal.

I feel like this is likely what is happening. What is the recourse? 

[Teddyhherrera]

5 minutes ago, PT20J said:

A quart every 6-8 hours is not atypical for a mid-time Lycoming. A lot of people run 6 quarts max and add when it gets down to 5. Some find that oil above 6 quarts gets blown out the breather. Another trick it to change oil type. I found that my oil consumption decreased when I switched from Aeroshell 100 to Phillips X/C 20W50. I've talked to others that had the opposite experience.

I've let mine get down to 5 on occasion with no discernable difference in performance. I'm going to really watch the next hours and change the oil at 30ish to see if there's any change

Edited October 25 by Teddyhherrera

[PT20J]

Just now, Teddyhherrera said:

I feel like this is likely what is happening. What is the recourse? 

You could always try a ring flush. https://www.savvyaviation.com/wp-content/uploads/savvy_pdf/savvy-oil-control-ring-solvent-flush.pdf

[PT20J]

3 minutes ago, Teddyhherrera said:

I've let mine get down to 5 on occasion with no discernable difference in performance. I'm going to really watch the next hours and change the oil at 30ish to see if there's any change

In my experience, it runs fine on 5 qts. If it gets down to 4, I start to see the oil temperature increase and the pressure decrease some. It will lubricate down to 2 qts (Lycoming's minimum spec.) but that's not really enough oil for cooling at cruise power.

[Teddyhherrera]

13 minutes ago, PT20J said:

You could always try a ring flush. https://www.savvyaviation.com/wp-content/uploads/savvy_pdf/savvy-oil-control-ring-solvent-flush.pdf

There's not a single person, I've spoken to that says this has worked for them. I think the score right now is 0- 12 between both online and at the airfield. I'm willing to give it a shot though

Edited October 25 by Teddyhherrera

[EricJ]

1 minute ago, Teddyhherrera said:

There's not a single person, I've spoken to that says this has worked for them. I think the score right now is 0- 12 between both online and at the airfield. I'm willing to give it a shot though

It works when the issue is accumulated crud in the ring lands, which is fairly common but isn't the cause of every cylinder ailment.   

[PT20J]

2 minutes ago, Teddyhherrera said:

There's not a single person, I've spoken to that says this has worked for them. I think the score right now is 0- 12 between both online and at the airfield. I'm willing to give it a shot though

It probably depends on what the problem is. I've talked to people that freed up a stuck compression ring and raised the compression with the technique. I don't personally know of anyone that has used it for high oil consumption, but @kortopateswould be the expert on this. At least is is simple and noninvasive.

[Teddyhherrera]

I'm taking this post to say thank you to you guys. Y'all have been helpful and supportive. It's very appreciated, great community...

[1967 427]

On 10/23/2024 at 8:25 AM, Teddyhherrera said:

That I don't. And that's part of the reason I'm apprehensive about  changing the cylinder. For the most part, my engine is extremely well behaved, no extremely high cylinder temps. I maybe see 425 on my hottest cylinder on initial climb out, oil runs cool, BUT my MX says it will only get worse

Higher than normal cylinder temps combined with the fact that you said you don’t get an RPM drop during mag run up check, says to me that you may have more than 20 degrees of advance on the timing.  Check timing this may solve some issues.

[Ragsf15e]

55 minutes ago, Teddyhherrera said:

1 every 6-8 hours. It spits down to 6 qts immediately and stays there for about 6-8 hours

That seems real good for oil consumption.

[Teddyhherrera]

9 minutes ago, 1967 427 said:

Higher than normal cylinder temps combined with the fact that you said you don’t get an RPM drop during mag run up check, says to me that you may have more than 20 degrees of advance on the timing.  Check timing this may solve some issues.

I don't have higher than normal cylinder temp and I do get a mag drop. It was out of tolerance for the right mag. I would get 2-300 on the right and have to really lean it out.

[MikeOH]

59 minutes ago, Teddyhherrera said:

There's not a single person, I've spoken to that says this has worked for them. I think the score right now is 0- 12 between both online and at the airfield. I'm willing to give it a shot though

Just to say it again, my oil consumption got WORSE after I tried the ring flush.  One more data point to keep in mind.

[Z W]

Just a thought - were you leaning aggressively for taxi and ground operations?  Many engines will foul a plug with lead deposits from fuel if you leave the engine full rich on the ground, especially if you're above sea level altitude.  It will present as a large drop in RPM and rough-running engine during the mag check.  The cure is to do a very lean run-up at possibly higher RPM (2,000 or so for a minute or two) and burn off the lead deposits.

[Shadrach]

11 hours ago, Teddyhherrera said:

1 every 6-8 hours. It spits down to 6 qts immediately and stays there for about 6-8 hours

What is the fill level at oil change?   

[Teddyhherrera]

10 minutes ago, Shadrach said:

What is the fill level at oil change?   

My AP puts 7qts

[Shadrach]

3 hours ago, Z W said:

Just a thought - were you leaning aggressively for taxi and ground operations?  Many engines will foul a plug with lead deposits from fuel if you leave the engine full rich on the ground, especially if you're above sea level altitude.  It will present as a large drop in RPM and rough-running engine during the mag check.  The cure is to do a very lean run-up at possibly higher RPM (2,000 or so for a minute or two) and burn off the lead deposits.

An IO360 with the fuel system set to factory specs will not typically have issues with lead deposits. Perhaps at very high DAs his might be an issue. Best course of action is probably to lean for the highest EGT as plug fouling is more a function of plug temperature than mixture. 

I have been in and around Lycoming engined Mooneys since birth. My father has owned a C, an E and an F model. He never leaned any of those airplanes for taxi. Lead fouled plugs were never an issue for him. DA’s at our 701’ drome vary from -3000 to nearly 4000’ depending on season.

[Shadrach]

7 minutes ago, Teddyhherrera said:

My AP puts 7qts

I typically do 6qts plus ~10oz camgaurd. Consumption depends on operations. 6-8 quarts an hour is perfectly healthy.