Deep LOP effect on plugs

[A64Pilot]

I’ve mentioned it a couple of times on the forum, but I’ve been running an experiment plug wise, as in not cleaning them and just running them until they exhibit misfire behavior during run -up. I’ve been doing this soon after I got the airplane three or four years ago and I think between 150 and 200 hours. I pulled the plugs yesterday and the pics are as pulled, no cleaning. They aren’t good pics but I think are good enough to show what I’m trying to. I rarely ever fly normal length flights, almost always well less than an hour and mostly low altitude as in 1,000 MSL and run DEEP LOP as in 50C lean of the factory EGT probe, in truth I don’t even bother peaking anymore as I fly at 55% power (8 GPH) and at that power you can’t hurt the engine with mixture so as soon as I level off I just set 23 squared and roll back the mixture to 8 GPH. Now I’m lean of best BSFC, but she runs butter smooth and gives me enough power for 135 kts which is enough for me, I’m primarily after long engine life and as I’m Retired I’m just not in the hurry I used to be, and it gives me great MPG.

Anyway I’m just going to reinstall the plugs, don’t see any reason to clean them and continue monitoring them and keep running the same. Motor does burn oil of course and whike I haven’t monitored it I’m pretty sure she burns more than 1 qt in 10 hours, more like 7 or 8 maybe so normal rate, but there is no carbon fouling from the oil, it’s burns off completely it seems.

 

 

 

Edited October 21 by A64Pilot

[N201MKTurbo]

Those plugs need to be gapped. They look way to big.

I run LOP and it keeps the plugs and cylinders clean, but I get lead deposits down in the bottom. I think it condenses down in the cooler regions of the plugs. Yours don't look like they have any.

[Fly Boomer]

35 minutes ago, A64Pilot said:

Anyway I’m just going to reinstall the plugs, don’t see any reason to clean them and continue monitoring them and keep running the same.

You should send your post to Mike Busch -- he would love it.  Your story has everything he promotes and practices.  First, LOP operations:  he always runs his TSIO-520s lean of peak.  And he, of course, is a proponent of "on condition" maintenance, which statistically lowers your chances of a maintenance-induced failure.  And saves money.

[MB65E]

I normally run BY plugs in the bottom and fine wires in the top. 
Cleaning plugs with the blaster wares them out more than flying does. Metal picks to get the crud out of them. 
But you’ll see and feel a failing plug on an engine monitor and in your seat. The ohm test will keep you running nicely too. 

Just don’t clean injectors just to clean them either. I’ve had deposits brake loose after cleaning. Not worth it.

-Matt

 

 

[A64Pilot]

2 hours ago, N201MKTurbo said:

Those plugs need to be gapped. They look way to big.

I run LOP and it keeps the plugs and cylinders clean, but I get lead deposits down in the bottom. I think it condenses down in the cooler regions of the plugs. Yours don't look like they have any.

Actually I believe two do, but they are deep up there. I had to get out in the sunlight to see them. I do have several picks I use to dig them out, but that would defeat the purpose of my experiment. I do pull the plugs Annually of course.

I think from a deposit perspective that running excessively LOP helps, just almost all engines except for this angle valve just can’t.

Everything else I’ve had I had to dig the carbon and lead out every 50 hours at oil change time. I’m against bead blasting even if using the correct media and glass beads isn’t the proper media. If I had a blasting cabinet with the proper media I would probably use it but I don’t. Blasting I think isn’t necessary, it does however make them look new.

They probably should be gapped, logically of course they open up as they wear but I didn’t. I need to buy a gapping tool, I’ve always run fine wires up to this point and didn’t need one until now.

Edited October 21 by A64Pilot

[Shadrach]

I never see lead deposits at the electrode. Any deposits are always found at the base of the internal insulator. They typically need to be picked out with a dental tool. I have never had deposits in sufficient quantities to have any effect on plug performance.

[A64Pilot]

2 hours ago, Fly Boomer said:

You should send your post to Mike Busch -- he would love it.  Your story has everything he promotes and practices.  First, LOP operations:  he always runs his TSIO-520s lean of peak.  And he, of course, is a proponent of "on condition" maintenance, which statistically lowers your chances of a maintenance-induced failure.  And saves money.

I disagree with a lot of what he sells to put it nicely, I think he goes too far, but I agree that the industry has also gone too far, repacking wheel bearings every year on an airplane that has flown ten hours and likely has ten miles on the bearings is I think excessive for instance.

There are two types of Maintenance, preventative and reactive. In my Career I’ve seen preventative save bunches of money and I think lives. Reactive you of course fix things after they break, but in Aviation often we can’t wait until then.

 

[redbaron1982]

4 minutes ago, A64Pilot said:

I disagree with a lot of what he sells to put it nicely, I think he goes too far, but I agree that the industry has also gone too far, repacking wheel bearings every year on an airplane that has flown ten hours and likely has ten miles on the bearings is I think excessive for instance.

There are two types of Maintenance, preventative and reactive. In my Career I’ve seen preventative save bunches of money and I think lives. Reactive you of course fix things after they break, but in Aviation often we can’t wait until then.

 

I do think Mike goes too far sometimes. But I'm not sure that what he proposes is reactive maintenance either.

There are three types of maintenance actually (from best to not so good):

• Predictive. You analyze the system to check if it needs to be repaired or not. For instance, vibration analysis in an electric motor. Or borescope imaging on aircraft cylinders and oil analysis.
• Preventive. You have an estimate of how much the part should last, and then you schedule to replace it when it is about to get to its useful life. 
• Reactive. You wait for the part to fail.

I think Mike proposes Predictive maintenance. Basically, repair is based on the part's condition.

Preventive maintenance is better than reactive maintenance, but it is not as good as predictive maintenance. Many factors can shorten a machine's expected life. For instance, a pilot with poor powerplant management can cause an engine to not make TBO.

 

[N201MKTurbo]

I use these in a pin vise to get the deposits from the bottom of the plugs. The vibrator is worthless IMHO.

https://www.aircraftspruce.com/catalog/topages/championcutter12-01147.php

[Fly Boomer]

1 hour ago, A64Pilot said:

There are two types of Maintenance, preventative and reactive. In my Career I’ve seen preventative save bunches of money and I think lives. Reactive you of course fix things after they break, but in Aviation often we can’t wait until then.

When I read Busch, I think he favors something in the middle -- don't overhaul something because it's time BUT don't wait until it breaks.  He is pushing an attitude that is continuously looking for things that are not broken, but also not quite right.  Then investigate the "not quite right".  Of course some things will outright break regardless of your maintenance philosophy.

[Hank]

1 hour ago, N201MKTurbo said:

I use these in a pin vise to get the deposits from the bottom of the plugs. The vibrator is worthless IMHO.

https://www.aircraftspruce.com/catalog/topages/championcutter12-01147.php

That's what I use, shoved into an engraver to vibrate.

But as long as I lean aggressively on the ground, hangar to runup and landing rollout to hangar, I don't have any buildup to clean.

[EricJ]

4 hours ago, N201MKTurbo said:

I use these in a pin vise to get the deposits from the bottom of the plugs. The vibrator is worthless IMHO.

https://www.aircraftspruce.com/catalog/topages/championcutter12-01147.php

I use that in an electric engraving tool as well and have had good luck with them.   They're quick to get the silica deposits out as well, which I usually find in other people's airplanes.

[N201MKTurbo]

I have the engraver and I find it works just as well whether plugged in or not. So I got a pin vise handle and mounted it with a pin (coat hanger wire) shoved in with it. It is much easier to use and does a better job IMHO.