Seneca Mx….

Hi All,

Quick Question….

First off, this may not be a question related to Seneca’s exclusively, but it happened to me and I’m driving a Seneca III right now.

I change the oil every 50hrs, and in doing so I also clean, check and gap all the Spark Plugs, seems to start and run a bit better. The engines are TSIO-360KB’s.

Everything goes smoothly except when I go to pull the Plugs and try to remove the Spark Plug Coupler Nut, it sticks. When I put some arm into it, I break the torque on the actual Spark Plug and both the Coupler Nut and the Spark Plug turn, and if I’m not careful I can twist the Magneto Lead Wire. I do not overtighten these Coupler Nuts, I just “snug ‘em down”, tightening IAW the Champion Service Manual V-6R Pg 11-12.

So, I now have to use 2 7/8’’ Special Wrenches to hold the Plug, remove the Coupler and then remove the Spark Plug. I hope that makes sense! To those who this has happened to, I’m sure it makes perfect sense…

So, out of my 24 Plugs, usually 22 of them do this. My IA who does my Annual says he sees it occasionally in larger TCM Engines. Another IA, who I work part time under as an A&P , says he never sees it. His experience is mainly on smaller Lycomings and TCM’s on -140’s and -172’s. Prior to this Seneca that was pretty much all I worked on as an A&P also, so this is new to me.

So, it’s been a bit of a hassle getting the Plugs out ‘cause ya gotta fight everyone of ‘em with the “2 wrench set up”.

My question is…

  1. Have any of you seen this happen, if so, what do you do about it, if anything? The first IA says it’s just the way it is…

I apply Anti-Seize Compound to the Plug threads sparingly IAW the same Champion Service Manual V6-R Pg 11 and have never had a problem with a Plug seizing in the Cylinder. They are torqued to 27.5 ftlbs IAW the PA-34 MM. Has anyone tried putting the Compound on the Coupler threads, to prevent the Nut from seizing on the Plug? The same Champion Manual however apparently Cautions against it on Pg 11. Not sure why? Thoughts?

Thanks in advance!

Stay Safe, Fly Fun!

George

N8434M KLPR



Comments

  • Hi George,

    Page 11 says never apply antiseize to the threads of the plug at the connector side but they don't say anything about the nut... ;)

    I have not had much trouble with these on my Seneca III but it might vary by the harness design too.

    Using something like this one the connector side might help. It is high temp, etc. You would not want to get any in the insulator area but it would certainly help with the threads.

    Eric


    Eric Panning
    1981 Seneca III
    Hillsboro, OR (KHIO)

  • Hi Eric,

    Thank You for the input and your suggestion!

    Yes, interesting differentiation in the Champion Manual! 😛 Any idea why Champion would publish that?? It’s nowhere near the Electrodes to cause Plug Aching and if applied correctly and sparingly, like you would, not close to the Spring Insulator? Putting the Anti-seize compound on the Nut side though, makes good sense too!

    I will give this a try and let you guys know how it works in 50 hours! 👍

    Thanks again Sir!

    George

    N8434M KLPR

  • I suspect they were worried someone would but so much on it would run into the connector area and would potentially cause a misfire. If you had a bunch on the threads and slid the spring and boot pass it you might redistribute a bunch of gunk.

    I think Champion should worry less about this and more about making a spark plug with a more consistent center electrode resistance. I use Tempest plugs.

    Tempest has an excellent manual and also cautions against putting anti-seize on the connector threads.... They have a great section on how do do adhesive blasting too.

    what torque setting are you using? Tempest says follow the harness instructions... It might also help to have a different tool like this crazy priced one. The connector "nut" seems like soft aluminum and may be distorted from prior efforts.


    Eric Panning
    1981 Seneca III
    Hillsboro, OR (KHIO)

  • Hi Eric,

    Thank You Sir for the input!

    Just looked over the Tempest Manual, quick question…

    Are you using their Fine Wire or Massive Plug??

    Ive never worked on or flew with the Fine Wire.

    If you use the Fine Wire, do you like them better? Wear wise, cost wise and the ability to clean? Do they run as smooth or smoother, last longer? The Manual touches on the cleaning them, sounds like just a few seconds of Black Diamond would do the trick. Am I reading that correctly?

    On the Anti-Seize Compound, I can see the over use mess. I used it sparingly just on the Coupler Nut. I’m “snugging” that Coupler Nut down. The PA-34 MM just states “tighten”, I’ve never seen a torque value.

    On the “Sparkplug Wrench”…. Yeah, I saw the price on Spruce, mine are 7/8”, and they run about $329. So my IA and I “local manufactured” a couple, one for the plug and the other for the coupler nut. Works well, just heated up and bent 90–ish degree angles into 2 Craftsman Box end wrenches, then took a dremel tool to open up the box end to accommodate the sparkplug lead. I told him he should market these things to the Snap On guy who comes by the Shop! 😜

    Sorry for being so long, I was just wondering if other guys had the same issue with their plugs and you bring up a bunch of interesting stuff!

    I see Hillsboro OR! I flew for Evergreen back 100 years ago, HQ was in McMinnville. Mr Del Smith, you may know all about them!? I was there for only about a year and flew the 727…

    A lot of history with that outfit! Our Chief Pilot flew for Elvis! 😳

    Thanks Again Eric!

    George

    N8434M KLPR

  • George, thanks for sharing and let us know how it turns out. I would also make the tool as you describe for the same reasons.

    On Sat I discovered I had a diesel leak in a Yanmar lift pump at the banjo fittings. The threads were shot and when I tried to tighten they just spun. The diecast Aluminium is no match for the steel bolt thread.... I ended up taking it all apart, and then hunting down M8-1.25 helicoils. Struck out at Home Depot and Ace Hardware but found some at Autozone. A quick drill, tap, and insert and I was back in business - no leaks.

    The cheap knock off pumps are ~ $40 and the official pumps are ~$160 but they are all die cast so I might just keep what I fixed.... The beauty of recreational boating is you can fix stuff....

    I have had fine wires and massive from Tempest. I have never seen any upside to the fine wires in the planes I have flown and have stock gapped massives driven by magnetos in the Seneca. Never had an issue with fouling in the TSIO-360's. Maybe an upside of the fixed wastegate (hot charge air)?

    The Evergreen story is a complicated one. I think the downfall was really the early demise of Michael King Smith in a car accident. Must have hit his father hard and they were bankrupt by 2014 after managing a 200+ airplane cargo fleet in the 80-90's.

    The museum is still operational and worth a visit.

    Eric Panning
    1981 Seneca III
    Hillsboro, OR (KHIO)

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