Well, regardless of the annealing vs. new discussion, I've had Tempest massives in my engine for more than a year, and I've been very satisfied. I had a lengthy discussion with the Tempest rep at either the AOPA Colorado Springs fly-in or at OSH (can't recall--getting old!), and although much of it was his sales pitch (sort of like preaching to the choir, since I already had them), his point was valid--they're so much better than Champs that Tempests are outselling Champs by a huge margin, once the A&Ps and IAs started installing them. According to him, their failure rate is almost non-existent--not absolutely 100%, but close.

On the issue of fine wire vs. massive electrodes, as I understand it, the fine wires theoretically last 3 times as long as the massives--but since they cost 3 times as much according to Tempest's price list, the cost difference is nil. My previous non-Tempests (I think they were Autolites, but not sure) lasted some 700 hours before being replaced with the Tempests. The fine wires also theoretically foul less often than the massives, but since I've not had any problem with massives fouling, that's a non-issue for me--might be for others, but as long as I remember to lean on the ground, which I do habitually, I just don't experience fouling. I think in all the time I've had this airplane, I've had only one spark plug which fouled, caused by idling too long without sufficient leaning at OSH while waiting to take off, and that was solved with a full power run-up and leaning.

Cary

For the record, I've got a box of 100 new copper gaskets. I'd personally not shy away from annealing an old one, but these were cheap so I bought them for ease of use.

I've also got 8 new UREM37BY that I'll install this weekend, so I'm glad to hear Tempest success stories!

Also, for the record, graphite is a conductor. So if you're using the appropriate anti-seize it should not be dielectric.

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CamTom12 wrote:Also, for the record, graphite is a conductor. So if you're using the appropriate anti-seize it should not be dielectric.
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…. sigh…

The waters are getting convoluted Here's some records for you ;

Resistivity and conductivity are reciprocals. In a conversation such as this, bringing up conductivity without addressing resistance nets very little, and nothing absolute

My initial post on this thread were solely based on the resistance I found in Champ plugs. My follow up was based on the added resistance of reusing impure gaskets.

The graphite in (Champion) anti seize is utilized for it's lubricating properties, the fact that it's a conductor is just an added (relatively cheap) bonus. While it is indeed true that graphite (Carbon) is a conductor, it's resistance is something on the order of 1000 times that of annealed copper, let alone pure bare copper. You can probably find a chart on the net, if you want the exact numbers as I'm not that sharp, but I'm 100% positive the difference is MASSIVE (no pun intended). In fact if conducting electricity to the plug was the goal, even iron would have been a better choice (based on resistance) than graphite.That is what I was alluding to here;

Rob wrote:... but are you talking about the same threads the vast majority apply a resistant anti seize to? That path is going to be determined by resistance, just like the throttle cables that get fried because the ground strap is bad...
Take care, Rob

and all of this is not too far away from why you can't take your GA headset and run it in your work bird (military vs GA impedance) while they both conduct just fine


One last time, I would anneal a gasket in a pinch, and agree we are splitting hairs, but the bottom line is (at least for me) there is value in splitting these hairs.


A short story

Several years back our chief pilot poo-pooed the vgs on my Thrush. His exact wording fails me now, but I believe it was something like 'how can a few 1/4" pieces of aluminum do anything remotely detectable in that 60' cantankerous wing'… As it was I was wrenching on something and had a set of dikes in my mitt, so I casually walked over and sized up the dikes to a VG. I then walked over to his airplane, grabbed on to his aileron trim tab approximately as deep into the dikes as to simulate a VG, and gave it a 1/4" tweak

OMG! he just about shit a purple twinkie… sideways…

Dan ; "Now why'd you go and do that! I'm going to have to get out a half dozen times for the next half dozen loads to get the old girl flying straight again"….

Rob: "Now Dan, surely one little 1/4" tweak to your trim tab can't possibly make a difference? after all, the 150 1/4" little VG's scattered across my wing don't "

A year or two later Dan and I are in Iowa for our summer gig, and haven't the luxury of a pressure washer in the barn. One morning Dan notices that every morning I get the rag I left in the grass the night before and use the dew to wipe off all the oil and aphids that accumulated on my leading edges the day before. In front of the fellas he gives me quite the ribbing… and I am OK with it.. but at dinner that night he asks what the deal is, after all it's not like I am washing down the airplane, just the LE and the prop. So I share that I once watched a video of a tufted wing at the stall, and in that vid it was very interesting (to me) for quite a bit before the increasing AOA approaching the stall, how little of the wing was actually flying. In fact it was only about the front 10" or so of the wing that was even doing anything at all the rest was very obviously just there for the ride. Consequently it was apparent to my feeble mind just how important a good LE was. After watching that vid, I religiously started cleaning the LE of my work plane before every day / night, and at least to me the difference was clearly noticeable.

Needless to say, the next day Dan was out wiping down the LE of his wing during his preflight, and it wasn't a day or two more before everyone else on the line jumped right in… Every year since then, we get a new pilot. As a general rule they don't show up with this habit, but also as a general rule they all leave with it.

Little differences… Some do some don't and also for the record, I wasn't trying to be argumentative, just sharing my thoughts, please feel free to disregard anything that doesn't make sense to you, it's exactly what I do when I read something that doesn't jibe to me.

Take care, Rob

Rob,

Wow, some folks have scary questions. Thank you for beating these home hand jam "wizards" off the thread.

Rob, that's a heck of a long reply. I'll try to address it but might miss something. On the cellphone telephone right now.

Correct, resistance is important. And you're right, carbon has 1000 times more resistivity than copper, either pure or annealed. It is still somewhere on the order of 10^-4 or 5 ohm-meters though, so pretty low. There is a small difference (somewhere on the order of 10^-9 ohm-meters) between annealed and non annealed copper. Real small. Not anywhere near on the same order of magnitude as the effect VGs have on a wing, but I see where you're going with your analogy. But, resistance is determined by both the material and it's cross sectional area, and I'd be willing to bet that the extremely small cross sectional area of the anti seize puts it at a lower overall resistance than the copper gasket. There's a way to test this, and I might if I have the time.

I still think that the sole purpose of the copper gasket is for sealing the plug to the head. The annealing process works because the copper gasket hardens with heat cycles and won't seal well if reused without annealing, which softens the copper again and allows it to seal again.

I would imagine that the electrical path from the ground strap to the stem of the spark plug and then back through the copper gasket to the head has more resistance than from the grounding strap to the threads and the thin, non-uniform layer of anti seize to the head.

I decided I'll test it this weekend and post my methodology and the results.

But, in the end this is a silly thing to argue over. I'd much rather read more of your ag flying stories. Those are always very fun to read and I love when you share them!

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You got it wrong Cam!! Start another thread with your home "theories".

8GCBC wrote:You got it wrong Cam!! Start another thread with your home "theories".

That's really productive. I can understand the need to be rude, since this is SUCH an important subject...

Hammer wrote:

8GCBC wrote:You got it wrong Cam!! Start another thread with your home "theories".

That's really productive. I can understand the need to be rude, since this is SUCH an important subject...

Please start another thread Better wording.

My apologies for defending the factory recommended procedures.

8GCBC wrote:You got it wrong Cam!! Start another thread with your home "theories".

I did get one thing wrong.

I just pulled the lycoming service instructions and they recommend a copper based anti-seize. Not a graphite one. So A, I'll be buying a new bottle of anti-seize and two, the resistivity discussion is now not relevant.

Also, for the record, the maintenance instruction (http://www.lycoming.com/Portals/0/techp ... _17_15.pdf) does call for a new copper gasket. It does not say why. The electrical conducting thing you mentioned is not in any publication that I've found. Seems like that is the "home theory." And that is what this discussion is all about: whether your "home theory" that the copper gasket's purpose is to serve as an electrical pathway is valid or not.

That's, like, your opinion, man.

Again, the ground is the copper gasket. Sparkplug threads go through hell and the threads are filled with lead, carbon, etc. Not a good place to bet a electrical ground on. The sparkplug Hole also expands and contracts which disrupts the threads from being a good ground too.

A SERVICE INSTRCUTION is for maintenance not design specs.

Use new clean copper if you like your mags and spark to be predictable.

Cam you are invited back to this thread. I may of got a little terse. . Me acting bad.

Rob wrote:... I once watched a video of a tufted wing at the stall, and in that vid it was very interesting (to me) for quite a bit before the increasing AOA approaching the stall, how little of the wing was actually flying. In fact it was only about the front 10" or so of the wing that was even doing anything at all the rest was very obviously just there for the ride. Consequently it was apparent to my feeble mind just how important a good LE was. After watching that vid, I religiously started cleaning the LE of my work plane before every day / night, and at least to me the difference was clearly noticeable....

Guess I'm gonna have to start wiping down the leading edge after every flight now.
Thanks a lot, Rob.

Well, Iv'e been circling the pattern here for a couple days now.
Not quite sure it is safe to land just yet, so may drop a couple notes out the window and scoot.

I tend to agree with some major points of Cary, Rob, 8GCBC, and that Smiling Cork guy. Sort of a standard old yes-but reply I guess.

Several spark plug manufacturers state in their informational sections that the
SOFT copper washers' primary function is, (during the initial crushing), to provide a tight seal against gas blow-by. Or, an air-tight seal. Of course there is an inherent grounding function to go with it. Should that be ground effect Contact?

Now, Plumbago, an archaic word for graphite, one of the softer materials, (some claim the softest known material), is a crystalline allotrope of carbon. Diamond is also an allotrope of carbon. Graphite is often described as greasy to the touch which helps to make it a partial lubricant as well as a pretty good conductor.

I chased down several Material Safety Data Sheets for a few "anti-seize" Mfg.s
Surprisingly they do not all conform to a "standard" format.

LIST: Just for starters:

Mineral Oil Hydrotreated (Severe) that may be wax as in car door lube.
Dripless Base Compound Thick oil ?!? Won't drip per some asea std.
Aluminum Flake
Copper
Benzoic Acid
Ad infinitem etc

Time to duck and run.

PS: Jet-Lube has the widest operating temp. range I could find. -65 to 900 deg.F

I dunno if the sparkplugs ground through the copper gaskets, through the threads, or by Bluetooth, but when I needed some anti-seize for them I bought Champion brand. Dunno what's in it but I figger they know what's best.

My final thoughts on the topic are these:

If the threads didn't offer enough contact for an electrical pathway, I would think the spark plugs would fall out of the head. 35 ft-lbs should allow for a significant metal to metal contact throughout the entire operating envelope. The thin layer of copper anti-seize that Lycoming requires should also provide an excellent electrical pathway as it fills the gaps in the threads, since it is thinner (significantly) than the thick copper washer. The longer electrical pathway through the spark plug body back to the copper washer should also provide more resistance (in the same material, a longer pathway = more resistance). A shorter pathway, say from the grounding strap to the threads, should provide less resistance. I still may test this, but on an old/dirty plug to validate those concerns.



Anyways, this has gotten silly and I'm done discussing it. I really enjoy thorough discussions, even if I do turn out to be wrong, but they're no fun when people can't exercise intellectual humility. Going into a technical conversation without thinking that there is a chance you could be wrong brings about a natural tendency to allow ego to take over. That's no fun for anyone. It's your idea of how a process works, not your credibility that's at stake. Almost any time the phrase "I'm right" or "you're wrong" is mentioned, the argument has gone beyond the subject at hand and people start defending egos over ideas. Not to say I've never done it, but it ruins the discussion.

My 2 cents.

"Admit it grounds through the gasket or you're entering a world of pain."

Everybody calm down.

We all want a good clean spark.

Hammer put the gun down man.

CamTom12 wrote: ... no fun when people can't exercise intellectual humility. Going into a technical conversation without thinking that there is a chance you could be wrong brings about a natural tendency to allow ego to take over. That's no fun for anyone. ..........

I've noticed that here before. A couple people in particular (who will go unnamed) seem to need to be always right, and even when shown to be wrong will not admit it. Nobody, I repeat, nobody is right every single time.
(not even ME! )

hotrod180 wrote:

CamTom12 wrote: ... no fun when people can't exercise intellectual humility. Going into a technical conversation without thinking that there is a chance you could be wrong brings about a natural tendency to allow ego to take over. That's no fun for anyone. ..........

I've noticed that here before. A couple people in particular (who will go unnamed) seem to need to be always right, and even when shown to be wrong will not admit it. Nobody, I repeat, nobody is right every single time.
(not even ME! )

I'm about 75% right (most of the time) enough to pass an FAA written.

Hammer wrote:

"Admit it grounds through the gasket or you're entering a world of pain."

(Gulp)