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Spark plug anti-sieze

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Grumpy Cynic
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Most of my air-cooled experience is with VWs.
Read a good article by a spark plug manufacturer (think it may have been NGK?) way back the 80s saying not to use any anti-seize on spark plugs - even aluminum heads. Basically said: "If you need to use it you are using the wrong spark plugs because of the wrong thread plating. Using anti-seize causes lots of problems from inaccurate torque to altered heat range". I don't remember all of the details but it was convincing enough that I quit using anti-seize on spark plugs. I've never had a problem since with good plugs in aluminum heads - either water or air-cooled.

Almost zero experience with the copper based goo on anything, much less plugs.
 

BJC

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Basically said: "If you need to use it you are using the wrong spark plugs because of the wrong thread plating. Using anti-seize causes lots of problems from inaccurate torque to altered heat range".
I've been using the correct spark plug, and the anti-seize that the plug manufacturer recommended and properly torqueing.

Lycoming now recommends using a copper based anti-seize (or engine oil) on the Plugs https://www.lycoming.com/sites/default/files/SI1042AH Approved Spark Plugs.pdf
I'm hoping to hear from someone who has been using the specific anti-seize product in mentioned in the OP.

Thanks,


BJC
 

pictsidhe

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I've used a variety of copper antisieze compounds and have never been able to tell the difference between them.. I always use copper stuff or failing that, engine oil on aluminum heads. No lycomings, yet.

The copper anti size compounds all turn to a lubricious dust if you keep them hot for a while. We use copious amounts at work on stuff that lives at 400-500F. Up to 4" 6tpi thread. If those ever galled, we'd be in a world of trouble, we have to strip them down every few months. We use own brand anti sieze from our consumables supplier, nothing fancy.

I'd therefore just grab any one from a decent brand and worry about something else.
 
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BBerson

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Aluminum anti-seize corroded my compression tester spark plug fitting in storage. The threads are gone.
 

rv7charlie

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I guess this falls in the 'follow mfgr's recommendation' category. IIRC, Rotax is specific to the point of demanding one specific plug thread treatment, specifically *because* of maintaining correct heat range.
 
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Pops

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Been using either Champion or surplus AF anti-seize for many years with no problems. Which ever I grab first I use. I sort of like the AF better because its a little thicker.
 
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lakeracer69

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We use a graphite product in suspension and paint it on the threads. Seems to work great with Lycoming or Continental. Torque to 360 inch/lbs for all of them.
 
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TFF

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I used C5 on turbines. It’s good stuff but it’s a lot thicker. The champion stuff can build up. I stop putting it on if it has been used religiously around mid time unless you get a tap and cut the old out stuff of the threads. 6 of one half dozen of another. They both can fowl plugs. The need for the anti seize to be conducive is important for radio reception.
 
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Dan Thomas

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Even Champion says not to use a graphite-based anti-seize, then they sell you exactly that.

Some copper-based anti-seizes also have graphite in them. Genuine Copper-Coat does not. Graphite is in the aluminum- and zinc-based products like Never-Seize. And in the nickel-based stuff. I have used all of them with success and no problems. One must avoid getting it on the last couple of threads so that it doesn't run into the electrodes and short them when things get hot. And you don't need much at all.

If a plug seizes in a Lycoming it will pull the helicoil out of the head. Might chew the head's threads up, too. Expensive. I wouldn't use engine oil (it varnishes and carbonizes and can glue the plug in there). I wouldn't use silicone sealant as one pilot on another forum was using. Besides acting as an insulator that limits the heat transfer out of the plug to the head, it crumbles when the plug is taken out and can end up in the ring grooves where it will lift the ring off its land, putting massive bending pressure on a single point and breaking the ring.
 
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Dan Thomas

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We use a graphite product in suspension and paint it on the threads. Seems to work great with Lycoming or Continental. Torque to 350 inch/lbs for all of them.
Lycoming specifies 420 inch-pounds (35 foot-pounds). Continental specifies 30 foot-pounds.
 

BJC

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There is a torque range for each: 30 foot pounds is the top of the range for Continental and the bottom of the range for Lycoming. But you knew that didn't you?
Lycoming specifies a single torque. From the link I posted above:

Spark Plug Installation Guidelines
1. Spark plug gap must be set at 0.016 to 0.022 in. (0.40 to 0.60 mm).
2. Always install a spark plug with a new gasket (P/N STD-295).
3. Use a copper-based anti-seize compound or engine oil on spark plug threads starting two full threads from the electrode, but DO NOT use a graphite-based compound.
4. Use installation torque values shown in Table 1.
Table 1 Installation Torque Values
Torque Value

All spark plugs
420 in.-lbs. (or 35 ft.-lbs.) (47.5 Nm)

5/8-24 (16 mm-24) lead nuts
80 to 90 in.-lbs. (9 to 10 Nm)

3/4-20 (19 mm-20) lead nuts
110 to 120 in.-lbs. (12 to 13.6 Nm)
 
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