Servicing my spark plugs

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astaib
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Servicing my spark plugs

Post by astaib »

Hello,

As I will do myself my next 50h visit, I want to service my spark plugs also.

I have the following tempest spark plug on my Lycoming engine : UREM38S.

If you also do it yourself, can you tell me what tools are the good ones to perform this task?
-Spark plug socket (7/8’’ socket, but what drive size and length?)
-Prolongator?
-Deviation if the sparks plugs are not accessible straight
-Gapper for fine wire spark plugs
-Gap gauge for fine wire spark plugs
-Anti-seize
-What else?

Do I have to rotate at 50h or only at 100h?
Do I have to change the spark plugs gaskets?

Other information are warmly welcome !!!

Thank you.

Arnaud.
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Rich
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Re: Servicing my spark plugs

Post by Rich »

Torque wrench
7/8" deep socket
Open-end or clawfoot for the harness attachment to the plugs. I use a clawfoot so I can torque them. 3/4" if I recall correctly.
You'll need an extension for the wrench to reach down inside the baffling.

Standard practice is to not reuse the gaskets. You can by them in batches of 50 at a time.
Do not get anti-seize on the electrodes.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Steve
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Re: Servicing my spark plugs

Post by Steve »

Hi Arnaud:

You have fine wire plugs, so it is not usually required to gap them.
I think we, in the US call it an extension, and 6-8 inches is good. No flex extensions are needed on our installation.
Torque wrench for reinstallation: set at 30-35 ft-pounds.
You will also need a 3/4 inch and 7/16 inch open end wrench (for the spark plug wires).
You do want to use anti-seize, and a new (or re-anneald if you are cheap) copper washer for each plug.
It is handy to use one of the spark plug holders to protect the plugs, and keep track of from which cylinder each one was removed:

https://www.aircraftspruce.com/catalog/ ... kkey=27851

Steve
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Rich
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Re: Servicing my spark plugs

Post by Rich »

The 7/8 socket itself needs to be what's termed here a "deep socket". If you have an extra plug laying around check it out beforehand.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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astaib
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Re: Servicing my spark plugs

Post by astaib »

Thanks guys, of course the torque wrench is mandatory, I forgot to list it.
Got it for the extension (better called than prolongator).
I will buy the copper gaskets and also anti seize.
Do you recommend the loctite copper one or the tempest one? Or we don’t care?

One question: if there is no need to gap them, maybe there is no need to remove them at 50hr visit?
If I remove them, shall I rotate them from bottom to top and top to bottom?

Thanks again.

Arnaud.
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Rick
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Re: Servicing my spark plugs

Post by Rick »

astaib wrote: Thu Jul 15, 2021 6:04 amOne question: if there is no need to gap them, maybe there is no need to remove them at 50hr visit?
If I remove them, shall I rotate them from bottom to top and top to bottom?
You might want to remove them to clean them. After 50 hours you will probably find carbon deposits inside the base. And then you can visually inspect them to verify they still look ok. You can also check the resistance while you have them out in case one is going bad... Also note - if you happen to have access to a spark plug cleaner, you should NOT sand-blast the fine-wire plugs! According to Tempest, they have some coating on them that is destroyed by sand-blasting, so they tell you NOT to clean them that way.
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Re: Servicing my spark plugs

Post by Rich »

I only remove plugs at annual. (That comes out to about 50 hours anyway. :cry: ) It is worthwhile to see how clean (or not) they are periodically.

Use the Tempest anti-seize. It's specifically for aircraft plugs.

Rotating top to bottom may or may not be worth it, but it's common practice due to a tendency for the low plugs to gather more contamination. In my case there's an argument that it's worthwhile as the plugs controlled by the Surefly (top on #2,4, bottom on 1,3) spark twice as much (every revolution) as the mag-fired ones, so over time the number of spark events get evened out.
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Re: Servicing my spark plugs

Post by Steve »

Same here as far as interval - at annual (about 50-60 hours). I use this anti-seize:

https://www.permatex.com/products/lubri ... lubricant/

because being a paste, it is easier to apply and stays where you want it (away from the electrodes). Have been using it for 20 years on the airplane without issues.
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Re: Servicing my spark plugs

Post by Lou »

Tempest has a good instruction sheet on cleaning plugs:

https://tempestplus.com/wp-content/uplo ... 081412.pdf
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