Fouled Fine Wire

[Dialed In]

Ok guys, I just would like your opinions on this fouled plug. I have had this plane for 500 hrs and not once had a fouled plug. The first 200 hours had old massive plugs then the last 300 I have had these Tempest fine wires. I run the plane 100 degrees rop because if I run lop it likes to push oil out the breather.  I did borescope the cylinders and they look fine, don’t have pics though left the computer at work.

 

I have 15 hours since the last annual and was doing a run up and the number two cylinder went dead on the left mag. I pulled the bottom plugs and found this on #2 as well as #3. The compressions are all 76/80 or better and the engine runs well.  I was surprised to find the lead buildup on these plugs that soon after annual, I’m speculating they did not clean the plugs and the lead balls that had accumulated at the base made their way up to the electrode.  Does this sound probable to you guys? Or do you think that much could accumulate over the last 15 hours?  The top plugs are lead free. TIA

-Chase

 

[Fly Boomer]

6 minutes ago, Dialed In said:

Ok guys, I just would like your opinions on this fouled plug. I have had this plane for 500 hrs and not once had a fouled plug. The first 200 hours had old massive plugs then the last 300 I have had these Tempest fine wires. I run the plane 100 degrees rop because if I run lop it likes to push oil out the breather.  I did borescope the cylinders and they look fine, don’t have pics though left the computer at work.

 

I have 15 hours since the last annual and was doing a run up and the number two cylinder went dead on the left mag. I pulled the bottom plugs and found this on #2 as well as #3. The compressions are all 76/80 or better and the engine runs well.  I was surprised to find the lead buildup on these plugs that soon after annual, I’m speculating they did not clean the plugs and the lead balls that had accumulated at the base made their way up to the electrode.  Does this sound probable to you guys? Or do you think that much could accumulate over the last 15 hours?  The top plugs are lead free. TIA

-Chase

 

Anybody know why LOP would push more oil overboard?

[PT20J]

Logbook entry should describe what was done to plugs at annual. Lead fouling is caused by rich mixtures (more lead) and low combustion chamber temperatures (poor scavenging). I would verify correct idle mixture, and perhaps lean more on the ground and try to keep the rpm at 1000 on the ground avoiding prolonged closed throttle idle. 

The only reason I can think of for LOP blowing oil out the breather is that the lower power results in reduced combustion pressure and may reduce ring sealing increasing blowby. 

Skip

[KSMooniac]

Lean very aggressively on the ground. Also verify that you have the proper fine wires for your engine too...maybe you have the wrong heat range and they're not getting hot enough.

I've never fouled my Tempest fines, but I fly LOP and lean aggressively on the ground.

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[Dialed In]

I guess I should have clarified some of my SOP’s as well. I run at 1000 rpm on the ground and do lean aggressively for this reason. I get about 35-40 rpm rise on shutdown so I’m fairly certain the idle mixture is set correctly and the servo was overhauled last year. Minus the lead buildup I thought the plug was very clean for a bottom plug that’s why I was surprised they fouled. There has been nothing in the logs that they have cleaned the plugs over the last two annuals, and there was nothing in the logs about installing new washers or installing the plugs back into the engine. Is it standard procedure to clean the plugs? I know they were pulled because I borescoped the cylinders both annuals. Does the color tell you guys anything?  I didn’t think it looked overly rich but I’m more familiar with 2stroke engines. Thanks again,

 

Chase

[Shadrach]

1 hour ago, Fly Boomer said:

Anybody know why LOP would push more oil overboard?

It wouldn’t. There may be a correlation butI the cause is likely something else.   

[EricJ]

+1 that the first thing to do, if you haven't been, is to lean heavily on the ground and don't idle less than 1000 rpm.   This minimizes lead fouling when the engine is cool.     Lean on the ground until it is just barely rich enough to run smoothly with the small power levels needed on the ground.   On many/most engines this is nearly to idle cutoff.

[Marauder]

I guess I should have clarified some of my SOP’s as well. I run at 1000 rpm on the ground and do lean aggressively for this reason. I get about 35-40 rpm rise on shutdown so I’m fairly certain the idle mixture is set correctly and the servo was overhauled last year. Minus the lead buildup I thought the plug was very clean for a bottom plug that’s why I was surprised they fouled. There has been nothing in the logs that they have cleaned the plugs over the last two annuals, and there was nothing in the logs about installing new washers or installing the plugs back into the engine. Is it standard procedure to clean the plugs? I know they were pulled because I borescoped the cylinders both annuals. Does the color tell you guys anything?  I didn’t think it looked overly rich but I’m more familiar with 2stroke engines. Thanks again,
 
Chase

Some shops won’t clean fine wire plugs. Probably because their spark plug cleaners are set up with an aggressive media safe for massives.

I spoke to Tempest and they said that only walnut shell media should be used to clean them. And I’m willing to bet a lot of shops reuse copper gaskets as well.

As for the fouling, I lean aggressively as well and although I never had a fouled fine wire, I have seen a fair amount of lead in one of them when I pulled it. I always thought it might be due to that particular cylinder was a little more richer than the others.


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[A64Pilot]

To me that plug looks hot, either your running very lean which it could be or it wrong heat range. It is normally much darker. So I don’t think not leaning has anything to do with it.

So far as blow by it shouldn’t, but maybe Pt20J is onto something, cant imagine any other plausible explaination.

If you look deep into the plug you will see some carbon, I’ve always used a very fine awl or dental pick to pick that out, but never blasted find wires myself, I think the only prohibition is to not use glass bead.

https://tempestplus.com/wp-content/uploads/2019/01/Sparkplug-Cleaning-The-Right-Way-081412.pdf

I’ve never lead fouled a plug before to be honest, and I’ve reused copper gaskets for a long time, occasionally I’ll anneal them.

 

 

[N201MKTurbo]

1 hour ago, A64Pilot said:

To me that plug looks hot, either your running very lean which it could be or it wrong heat range. It is normally much darker. So I don’t think not leaning has anything to do with it.

So far as blow by it shouldn’t, but maybe Pt20J is onto something, cant imagine any other plausible explaination.

If you look deep into the plug you will see some carbon, I’ve always used a very fine awl or dental pick to pick that out, but never blasted find wires myself, I think the only prohibition is to not use glass bead.

https://tempestplus.com/wp-content/uploads/2019/01/Sparkplug-Cleaning-The-Right-Way-081412.pdf

I’ve never lead fouled a plug before to be honest, and I’ve reused copper gaskets for a long time, occasionally I’ll anneal them.

 

 

I've always used glass beads to clean spark plugs. I have NEVER EVER seen the effects shown on that document! I have looked at them under much higher magnification then they show in that document. I can only guess that they were using some crazy high pressure.

[Rjfanjet]

I've been using TCP as a fuel additive to reduce the lead. Seems to work for me.