Spark Plug Troubleshooting

[Danb]

Chris I installed the fine wire plugs soon after I got the bravo the plane had under 100 hours on it, my starts both hot and cold have been better, I changed them even though the  massives were basically new, you would think Mooney in 2005 would have used fine wires. 700 hours later the plugs have been no issue. The MSC at my first annual recommended I change to the fines.

[Bob_Belville]

1 hour ago, rbridges said:

I did some digging on Mooneyspace and came across another thread that recommended these. My IA said my plugs were getting pretty worn but they were running fine. Anyway, just installed them with .015-.018 gap. I thought about fine wires but I'm at 1100 smoh and figured massive would get me close to the next oh. 

I bought a factory new IO360A1A from Norm Bender about 35 years ago. I had him move my fine wire plugs to the new engine.

[Danb]

Hey Bob I'll be flying over your field tomorrow about 9:30 I'll wave to you.

[Bob_Belville]

28 minutes ago, Danb said:

Hey Bob I'll be flying over your field tomorrow about 9:30 I'll wave to you.

Where are you headed Dan?

[Danb]

KILG to Kceu Clemson, did same on Friday. Bringing a kid to college, had a funeral. I went right over top Mrn 

[Marauder]

KILG to Kceu Clemson, did same on Friday. Bringing a kid to college, had a funeral. I went right over top Mrn 

Bob's house was the one with 4 acres of tomato plants.


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[Marauder]

Ok. Quick update to this thread and a request. Paul from this site reviewed my upload to SavvyAnalysis and confirmed what I was seeing. One spark plug completely failed with a very high ohm reading. The second plug on that cylinder was failing and periodically during the run-ups failed completely as well. I replaced both Champion REM-38E with two brand new plugs I had in my emergency repair tool box. Both plugs were 24 years old but both ohm'd out fine. The subsequent run-ups were fine and I have been running with them for the last few flights with no additional issues.

Here is what the run-up looked like during the problem period:

So, after deciding 965 hours is probably enough on these plugs, I will be ordering a replacement set of plugs. After a discussion with Paul, watching the Busch video on spark plugs, I will be ordering a set of Tempest fine wires. I would also like to replace the existing non-waterproof harness with a new waterproof harness. What has everyone's experience been with Kelly's Champion and Slick harnesses? Any preferred place to buy them?

I am traveling this week but would like to place an order so they will be here next week. Any suggestions?

 

[Marauder]

Can one of the IAs please check my math? I am going with the fine wire Tempest and upgrading the harness from a 5/8" B nut to the 3/4" waterproof ones. I think I need based on my engine being an IO-360A1A with TCM S4LN-200 mags (part number 10-163005-11, stock # LW-163005-11) the following;

Tempest fine wire URHM38S (there is an XL after the name but this is what I will be ordering: https://www.aircraftspruce.com/catalog/eppages/temptestplugs10.php )

Kelly Harness, part number KA12360 (straight connector, no 90 degree bend). (can anyone tell why there would be 20 degree and 25 degree harness with the same part number?): https://www.aircraftspruce.com/catalog/eppages/kellyharness-blue.php Reference guide: https://www.aircraftspruce.com/catalog/pdf/kellyharnessapplication-1.pdf

I get this right? Looks like the Kelly harnesses are on backorder. This normal?

[Andy95W]

Chris- I believe you've got the right numbers.

I think the difference between the 20° and 25° is simply the timing to the engine, either 20° or 25° BTDC, per the Lycoming Service Bulletin that others have talked about here.

Why do you want to change from the 5/8" plugs for your engine and just keep using your existing harnesses?

[Marauder]

Chris- I believe you've got the right numbers.
I think the difference between the 20° and 25° is simply the timing to the engine, either 20° or 25° BTDC, per the Lycoming Service Bulletin that others have talked about here.
Why do you want to change from the 5/8" plugs for your engine and just keep using your existing harnesses?

My harness is pretty old. My mechanic kept repairing it over the years by replacing a few of the ends. I noticed that when I had the cowling off to replace the plugs, I am starting to see the braiding fail on some of the leads. I have seen more modern harnesses that have a protective coating over the leads.

Also, I believe the 3/4" fittings are considered waterproof (at least that is what I gathered from Busch's video). Since I do fly in rain, thought he was a good time to convert them. Here is what one of the leads look like:




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[carusoam]

My C's harness looked pretty ragged.... swapping them out got some new parts all the way back to the mags and got some pretty colorful rubber coated wires to go with them.

Done on a CB's budget.

Best regards,

-a-

[Andy95W]

23 hours ago, Marauder said:

 

My harness is pretty old. My mechanic kept repairing it over the years by replacing a few of the ends. I noticed that when I had the cowling off to replace the plugs, I am starting to see the braiding fail on some of the leads. I have seen more modern harnesses that have a protective coating over the leads.

Also, I believe the 3/4" fittings are considered waterproof (at least that is what I gathered from Busch's video). Since I do fly in rain, thought he was a good time to convert them. Here is what one of the leads look like:




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Well, there's your problem. Your ignition lead isn't connected and your spark plug/paper towel is probably WAY more than 5k ohms.

I never said I was as good as Clarence. Maybe he can find more stuff wrong. 

[Marauder]

Well, there's your problem. Your ignition lead isn't connected and your spark plug/paper towel is probably WAY more than 5k ohms.
I never said I was as good as Clarence. Maybe he can find more stuff wrong. 

The last of the true A&P troubleshooters. Not sure how I missed that!


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[Jim F]

Hi Chris,

Good choice on the fine wires. If it was my money I would do fine wires. I don't think anyone answered your gap question. Use the tool in the picture the .019 should not go and .015 should go. Most likely you won't have to adjust the gap on the fine wires. 

5/8 and 3/4 B-nut harness both are water proof you can see the seal as part of the insulator. The timing difference is interesting as the timing difference is the mag to engine and I can't guess why there would be a difference. Maybe interference on the accessory case. 

Dont abrasively clean the fine wires you only remove the lead. Also there is a polarity to the mags spark. When you pull your plugs  and you have them in the spark plug tray you swap #1 bottom with #2 top and continue when you get to #4 swap #4 bottom with #1 top. When you don't do this on massives you see football shaped center electrodes and thin side electrodes. Fine wires are not really a problem on this. 

Enjoy your new investment. 

Jim

[Marauder]

Another update. I finally was able to have the plugs and wires swapped out. I replaced the mag harness is with a new waterproof harness set from Kelly:

For plugs, I went with Tempest fine wires. While the plugs were out, I took a few pictures of the inside of the cylinders with a borescope. My engine is approaching a thousand hours on this rebuild. All the valves looked fine.

I also had the IA check and tweak the mag timing. Both are now set at 20 degrees. One was a bit low.

Final conclusions? Well worth it. The engine cold started started crisply without any stumbling. Runup showed each mag showing less than 50 RPM drop. On the test flight I noticed a smoother running engine. I also noted a couple of knots faster TAS on the entire flight for a power setting I normally fly. Not sure if that was real but will be pleasantly surprised if it is.

As for the post fueling hot start procedure? Huge improvement. I follow the Maxwell, "leave everything where it is on shutdown" process. It usually wiil take me 5 to 7 revolutions for the engine to catch and it will stumble badly for a second or two. The post work hot start is now 3 revolutions and a smooth running engine. I'm impressed.

[Guest]

Chris,

What borescope are you using, your pictures are very clear?

Clarence

[Marauder]

Chris,
What borescope are you using, your pictures are very clear?
Clarence

This one: http://www.oasisscientific.com/vividia-va-400-rigid-usb-articulating-borescope-videoscope-inspection-camera.html

Pictures taken with my Samsung S6 using an app called CameraFi.


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[Marauder]

And for the Paul Harvey moment...

These are the results of the resistance checks on the plugs after I pulled the Champion massives with 475 hours on them (#2 cylinder's were replaced 10 hours ago with massives I had):




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[carusoam]

I just liked the spark plug box that is personalized...

-a-

[Bob_Belville]

17 hours ago, Marauder said:

 

Another update. I finally was able to have the plugs and wires swapped out. I replaced the mag harness is with a new waterproof harness set from Kelly:

For plugs, I went with Tempest fine wires. While the plugs were out, I took a few pictures of the inside of the cylinders with a borescope. My engine is approaching a thousand hours on this rebuild. All the valves looked fine.

I also had the IA check and tweak the mag timing. Both are now set at 20 degrees. One was a bit low.

Final conclusions? Well worth it. The engine cold started started crisply without any stumbling. Runup showed each mag showing less than 50 RPM drop. On the test flight I noticed a smoother running engine. I also noted a couple of knots faster TAS on the entire flight for a power setting I normally fly. Not sure if that was real but will be pleasantly surprised if it is.

As for the post fueling hot start procedure? Huge improvement. I follow the Maxwell, "leave everything where it is on shutdown" process. It usually wiil take me 5 to 7 revolutions for the engine to catch and it will stumble badly for a second or two. The post work hot start is now 3 revolutions and a smooth running engine. I'm impressed.

Only one question - smart, analytic guy like you - what took you so long? 

[Guest]

10 hours ago, Marauder said:

 

This one: http://www.oasisscientific.com/vividia-va-400-rigid-usb-articulating-borescope-videoscope-inspection-camera.html

Pictures taken with my Samsung S6 using an app called CameraFi.


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Thanks,

I have the camera, I'll have to try that app.

Clarence

[Marauder]

Only one question - smart, analytic guy like you - what took you so long? 

Hmmm, money? I was just getting ready to pull the cord on the ADS-B upgrade. Didn't need that extra expense.


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[Marauder]

I just liked the spark plug box that is personalized...
-a-

Special gift from another MooneySpace member. Really like it.


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[Yetti]

Convinced.  Ordered half a set of Tempest fine wires....

[Rich]

I will be replacing my massive electrode plugs with fine wire plugs soon. I have the IO550 in my Ovation 2. I have been unable to find the difference between the Tempest URHB32S and URHB36S. Can anyone advise me on which would be best and why? Thank you in advance for any assistance.