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Auto plug adapter recommendations?

jcarne

Well Known Member
Patron
Hello, many of the threads on this topic appear to be old so the data may no longer be accurate.

So, what does everyone recommend for auto plug adapters? I have read a lot of negative comments on the ones supplied from Emagair. A lot of good on the Lightspeeds.

The biggest reason I ask is I’m trying to find out if anyone knows of quality adapter that have been tested and don’t cost $100!

Thanks in advance!
 
Last I checked, Klaus won't sell adapters separately from an ignition system.

I'm using long reach adapters from SDS.
 
Last I checked, Klaus won't sell adapters separately from an ignition system.

I'm using long reach adapters from SDS.

Oh I forgot about SDS, thanks for the recommendation. I’ll look into them.
 
I bought mine from flyefii. Much nicer than the ones that came with the p-mags. No experience with the SDS adapters, but I'm confident that they would be top notch as well.
 
It’s the nature of online forums that all you hear are negative reports on things...so I’ll just say that I have four airplanes with dual P-Mags, and that makes a total of...uh...32 of theirs adapters. Never had a problem with any of them!

Paul
 
It’s the nature of online forums that all you hear are negative reports on things...so I’ll just say that I have four airplanes with dual P-Mags, and that makes a total of...uh...32 of theirs adapters. Never had a problem with any of them!

Paul

Aww c’mon Paul, that’s strictly anecdotal. It’ll never hold up in court! ;)

I have almost 1800 hrs on my Pmag adapters; think I’ve replaced two over the years, but no real failures...
 
Read the manual's

Note that Klaus/Lightspeed specifies installing the adapter in the engine then the sparkplug in the adapter. This means the copper gasket between the adapter and the engine does not need to be replaced when the plugs are changed/removed. My engine came with a Plasma III and I've continued to use the adapters after changing to a PMAG. From the Lightspeed ignition manual:

• Install adaptors in cylinder head using the supplied copper washer.Torque to 35 - 45 ft-lbs using anti-seize compound.
• Install automotive style spark plugs with their washer. Torque to 20 ft-lbs usinganti-seize compound.

Regards,
 
I bought the adapters from an outfit in the UK. Bought them via ebay. quality and price were good but needed a little touch up on the lathe. Have held up well.
 
Thanks for the replies so far everyone. I fully understand that only a couple of negative reviews on the forums can speak loudly but $98 bucks for a couple of very simple brass pieces? I’m not okay with that. Yes, $98 bucks over the course of a build is small potatoes but tell yourself that 20-30 times and tell me what happens.
 
Read ALL the manual’s....

Note that Klaus/Lightspeed specifies installing the adapter in the engine then the sparkplug in the adapter. This means the copper gasket between the adapter and the engine does not need to be replaced when the plugs are changed/removed. My engine came with a Plasma III and I've continued to use the adapters after changing to a PMAG. From the Lightspeed ignition manual:

• Install adaptors in cylinder head using the supplied copper washer.Torque to 35 - 45 ft-lbs using anti-seize compound.
• Install automotive style spark plugs with their washer. Torque to 20 ft-lbs usinganti-seize compound.

Regards,

I agree that reading the manuals is a good idea - and in this case, the PMag manual suggests exactly the opposite of what Klaus writes - never torque the adapters to the heads without a plug installed in them. The thrust can be that you collapse the adapter. Perhaps this is the reason that some have reported problems with damaged adapters....

I can see nothing wrong with the PMag method, except that you have to find the right socket that will grab the adapter while fitting over the installed spark plug - my Champion plug socket works fine.

Theoretically, with the torque on the adapter higher than that on the plug, the plugs should always come out and leave the adapter in the cylinder after the first time you install it. I find that sometimes the adapters still come out.

Paul
 
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Another option is to use a plug that doesn't require the adapter. A couple of examples would be:

Autolite 386
NGK AB6

I am presently testing the NGK and so far I am pleased with it.
 
EMag plug adapters

Currently I use two EMags and EMag plug adapters. I follow the EMag instructions literally and torgue the plug only. The end result of this procedure is that the adapters will sometimes be removed with the plug. From some of the comments in this thread it appears like others are torqueing the adapters to a higher reading after the plug and adapter are torqued. Is this common practice. If so, what torque value is used. Thanks

Paul
 
I'm confused

Paul (Dye),

I was trying to point out that there are different direction from different suppliers and it seemed following the specific directions from the supplier was best. I always guessed the different installation directions were because of something different in the adapters. I don't really know. I'm confused by your description. I have the utmost respect for you and Ross.

My reading of the PMAG manual does not include directly torqueing the adapter.

The PMAG manual says:
"First, install adapters with the supplied gasket on the spark plugs finger tight. Then, insert the combined assembly (plug with adapter) in the engine and tighten to 18 ft/lb (standard auto plug torque) through the spark plug ONLY. Do not torque the adapter itself.

Note 1: If you install and torque the adapters separately, stresses will be focused at the adapter neck and can cause it to fail during installation."

When I've torqued through the spark plug, I then usually end up with the adapter coming out when I remove the plug. The PMAG directions don't seem clear to me about how to proceed if the plug comes out and the adapter does not. I have interpreted the PMAG method to mean always remove the adapter when removing the spark plug and follow the quoted instructions for re-installation.

Regards,
 
Anyone know of an adapter I can now use on my compression tester so I don't have to pull the autoplug adapters out each conditional?
 
Just need two hose adapters

I have both 14 and 18mm quick connect hose adapters, because usually some 14mm plugs bring the adapter out with them, some don't.
 
Paul (Dye),

I was trying to point out that there are different direction from different suppliers and it seemed following the specific directions from the supplier was best. I always guessed the different installation directions were because of something different in the adapters. I don't really know. I'm confused by your description. I have the utmost respect for you and Ross.

My reading of the PMAG manual does not include directly torqueing the adapter.

The PMAG manual says:
"First, install adapters with the supplied gasket on the spark plugs finger tight. Then, insert the combined assembly (plug with adapter) in the engine and tighten to 18 ft/lb (standard auto plug torque) through the spark plug ONLY. Do not torque the adapter itself.

Note 1: If you install and torque the adapters separately, stresses will be focused at the adapter neck and can cause it to fail during installation."

When I've torqued through the spark plug, I then usually end up with the adapter coming out when I remove the plug. The PMAG directions don't seem clear to me about how to proceed if the plug comes out and the adapter does not. I have interpreted the PMAG method to mean always remove the adapter when removing the spark plug and follow the quoted instructions for re-installation.

Regards,

You’re right - their current recommendation is to torque just the plug, and to be honest, I have done it both ways. My understanding of the mechanics is that the adapter can’t “collapse” if there is a plug in it, no matter how hard you torque on it (within reason, of course), and the design of the aircraft-plug-to-cylinder seal is such that aircraft plug torque is appropriate for the standard copper gasket - so following that idea, you do the dual torquing, so both “joints” get their design torque.

I can’t see anything wrong with that logic from an engineering or mechanical standpoint, but I have no religious convictions about it - as long as you don’t have a spark plug back out in flight, and you don’t damage anything on installation, you should be good.

Paul
 
You’re right - their current recommendation is to torque just the plug, and to be honest, I have done it both ways. My understanding of the mechanics is that the adapter can’t “collapse” if there is a plug in it, no matter how hard you torque on it (within reason, of course), and the design of the aircraft-plug-to-cylinder seal is such that aircraft plug torque is appropriate for the standard copper gasket - so following that idea, you do the dual torquing, so both “joints” get their design torque.

I can’t see anything wrong with that logic from an engineering or mechanical standpoint, but I have no religious convictions about it - as long as you don’t have a spark plug back out in flight, and you don’t damage anything on installation, you should be good.

Paul

I'd torque the plug and adapter combo to 18, then get the bigger socket and torque the adapter to its torque spec.................
 
Will the standard harness fit on these plugs?

Another option is to use a plug that doesn't require the adapter. A couple of examples would be:

Autolite 386
NGK AB6

I am presently testing the NGK and so far I am pleased with it.
 
Anti-seize

Are guys putting anti-seize on BOTH the spark plug threads AND the external threads of the adapters? I have dual P-Mags and I agree, the manual leaves it up to interpretation here.
 
Has anyone heard of an adapter (torqued or not) to back out while the engine was running?

Bevan
 
NGK recommends dry

Yes, I anti-seize both.

NGK recommends installing dry:

https://ngksparkplugs.com/en/resources/5-things-you-should-know-about-spark-plugs

5 THINGS YOU SHOULD KNOW ABOUT SPARK PLUGS

1. Anti-seize

NGK spark plugs feature trivalent plating. This silver or chrome-colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal. NGK spark plugs are installed at the factory dry, without lubrication or anti-seize.

Anti-seize can act as a lubricant, altering torque values up to 20 percent, increasing the risk of spark plug thread breakage and/or metal shell stretch. Thread breakage can sometimes involve removing the cylinder head for repair. Metal shell stretch changes the heat rating of the spark plug and can result in serious engine damage caused by pre-ignition. Do not use anti-seize or lubricant on NGK spark plugs. It is completely unnecessary and can be detrimental.

2. Corona stain

Corona stain is a light brown or tan discoloration on the outside of the ceramic insulator above the metal shell/hex. Corona stain is created by the high voltage traveling thru the plug that attracts the dirt or oil particles surrounding the exposed ceramic insulator between the wire/coil boot and spark plug metal shell. Corona stain is completely normal and should not be mistaken for exhaust gas blow-by or a broken seal inside the spark plug.

3. Gapping fine-wire spark plugs

While most NGK spark plugs are pre-gapped, there are occasions when the gap requires adjustment. Care must be taken to avoid bending or breaking off the fine-wire electrodes. NGK recommends a round wire-style or pin gauge gap tool to measure the gap. If the gap must be adjusted, use a tool that only moves the ground electrode and does not pry between or against the electrodes. NGK also recommends adjusting the gap no more than +/- 0.008” from the factory preset gap.

4. Torque

Torque is crucial in the ability of the plug to dissipate heat and perform properly. Always follow the manufacturer recommended torque specification. An under-torqued spark plug can lead to excessive vibration and improper heat dissipation, causing spark plug and/or engine damage. Over torquing may cause any of the following: thread damage/breakage, compromised internal seals leading to gas leakage, metal shell stretch leading to poor heat dissipation and pre-ignition.

5.“Copper spark plugs”

“Copper spark plugs” is a term often used to describe a standard material spark plug. However, this terminology is incorrect, as standard material plugs do not have electrodes made from copper. Copper is soft with a low melting point and cannot be used for electrodes, as they would wear very quickly. A standard material spark plug uses a nickel-alloy that may include a small copper core. The copper core has nothing to do with the electrical performance of the spark plug. A copper core is used to increase heat dissipation and durability by lowering the electrode temperatures. Nearly all NGK spark plugs, including precious metal iridium and platinum plugs, have a copper core to increase the electrode durability. Special nickel alloys, platinum, and iridium electrodes, along with copper cores are all used to enhance durability – durability meaning how long a spark plug will last before it needs to be replaced.
 
Aircraft Spruce sells both LSE and Emag supplied adapters. I have begun replacing the adapters (LSE) at around 1000 hours, as they erode somewhat. Specifically, it is difficult to get the adapter threads started in the cylinder.

Interestingly, the torque values that were recommended when I installed the LSE system in 2007 or so were 25/15 ft-lbs, for the adapters and plugs, respectively. I've never had one come loose, and don't recall learning the recommended values had been increased.

Someone mentioned they are brass - the LSE ones show aluminum bronze alloy in Spruce's catalog.
 
I installed 4 adapters from here,
https://www.sparkplugadapters.com/products-1

These adapters are steel. $6.00 each.

Best to avoid steel adapters. Conducted heat transfer from plug body to cylinder head is a big deal. The vendors rarely identify which steel they are using. All steels have a low coefficient of thermal conductivity as compared to (for example) aluminum bronze, some being much, much lower.

Doesn't mean a steel adapter cannot be used, but a colder plug might be needed to do it safely.
 
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Another option is to use a plug that doesn't require the adapter. A couple of examples would be:

Autolite 386
NGK AB6

I am presently testing the NGK and so far I am pleased with it.

Note that the AB6 is a non resistor plug. I have tried them with resistor packs in the connector and still got noise in my system. Proceed with caution, though I never tested them without the external resistor pack. I have, however used the LR4U's and got a noise free environment. These are a bit colder than the 386's I was using in the 6 and that is why I tried them. The specs say that they are non-resistor plugs, but they have operated noise free in the 6 for 100 hours and I ran them in the 10 for a couple of hours, also noise free. I believe it is a better alternative to the 386. The 386's also had either cheaper metal or coating, as corrosion was a bigger issue than on the LR4U's.

Larry
 
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Not recommended by Emagair

Another option is to use a plug that doesn't require the adapter. A couple of examples would be:

Autolite 386
NGK AB6

I am presently testing the NGK and so far I am pleased with it.

Emagair does not recommend 18mm auto plugs:

https://emagair.com/service-notes/

18MM Thread Auto Plugs: NOT RECOMMENDED. We hear of customers occasionally using auto plugs that are manufactured with 18mm thread (avoiding the need for spark plug adapters), we have at least two reports from customers who tried 18mm thread plugs – with very poor (near disastrous) results. We recognize there may be a great many plugs that will perform perfectly well in this environment, but we also recognize that some do not. We recommend that most customers stay with plugs that have a known service record. IF you choose to experiment with other plugs (not recommended), do so with caution.
 
Since the use of non resistor plugs use has come up, I'm once again compelled to provide the first hand account that this should be undertaken only with extreme caution. This is not a "noise" issue in the respect that you will hear a crackle in the headsets - it is in fact a significant EMI issue that will literally scramble the brains of some EI systems to the point of being a legitimate safety of flight issue. The ONLY issue I ever had with my long history with Pmag use was a direct and absolutely confirmed use of non resistor NGK plugs I purchased by accident. Long story short, the non resistor NGK's literally scrambled the brains of the Pmags and rendered the ignition system "unflyable" - popping through the pipes, high EGT, screwed up timing, etc. installation of the specified BR8ES plugs INSTANTLY resolved the problem.

DO NOT use non resistor plugs without a legitimate flight test program.
 
Ya as awesome as an 18mm plug sounds there isn’t enough of a positive and supported record for my tastes. I think at this point I’ll go with either flyefii or light speed if I can score them. Thanks for the recommendations everyone!
 
Since the use of non resistor plugs use has come up, I'm once again compelled to provide the first hand account that this should be undertaken only with extreme caution. This is not a "noise" issue in the respect that you will hear a crackle in the headsets - it is in fact a significant EMI issue that will literally scramble the brains of some EI systems to the point of being a legitimate safety of flight issue. The ONLY issue I ever had with my long history with Pmag use was a direct and absolutely confirmed use of non resistor NGK plugs I purchased by accident. Long story short, the non resistor NGK's literally scrambled the brains of the Pmags and rendered the ignition system "unflyable" - popping through the pipes, high EGT, screwed up timing, etc. installation of the specified BR8ES plugs INSTANTLY resolved the problem.

DO NOT use non resistor plugs without a legitimate flight test program.

Mike makes a very important point here. With SDS CPI, CPI-2 or EM-5 systems, ALWAYS use resistor plugs and suppression wires.

I've seen even OEM auto ECUs scrambled by using non-resistor plugs and recently had a SDS customer who'd been flying SDS for a over a decade with zero problems suddenly have the engine barely run. Some work had been done on the engine mechanically so that was the suspect, went over the whole engine, injectors, regulator, fuel pressure, finally sent him a new ECU to try, same thing and we found no ECU issues when we tested his old one.

We collectively scratched our heads for several weeks as the symptoms were not consistent. I finally asked if he'd changed the plugs or wires recently. The plugs had been changed a couple month back during the other work.

The parts guy had handed my customer non-resistor versions of the plugs he took to the counter. Switched those out for resistor types and the problem was totally gone. There was no indication of ECU issues but the plug wires were close to the injector wires and the main symptom was serious and random flooding as though the injectors were being held open much longer than commanded by the ECU.
 
head scratching

My question is then whether dry would be recommended for installation in the brass adapters that emag provides, since that is a metal dissimilar to most cylinder heads found in automotive applications. Obviously, NGK is not manufacturing these plugs (specifically) for use in our application. Any thoughts??
My guess is that there is a lot of head scratching going on. I know when I read that NGK does not recommend any kind of anti-seize on the threads, I was pretty surprised. I had already installed with Champion spark plug anti-seize. I have not used it on the spark plugs after, and I have not cleaned off the leftover anti-seize. I guess I'll use it on the threads between the adapter and the cylinder as Champion recommends, and not between the spark plug and the adapter as NGK recommends.
 
My guess is that there is a lot of head scratching going on. I know when I read that NGK does not recommend any kind of anti-seize on the threads, I was pretty surprised. I had already installed with Champion spark plug anti-seize. I have not used it on the spark plugs after, and I have not cleaned off the leftover anti-seize. I guess I'll use it on the threads between the adapter and the cylinder as Champion recommends, and not between the spark plug and the adapter as NGK recommends.

I have used the Champion anti-seize as well. Has anyone found getting the spark plug out of the adapter difficult? Seems like it takes a lot of force and I definitely don’t over torque them when I put them in, I follow the emag directions. Also, I know they are called 14mm adapters but what is the thread on the inside of the adapter, e.g., m14 x 1.5?
 
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Just a word of caution on the adapters... i bought the eMag version from ACS. I have Lightspeed III ignition that i purchased from another builder.

They work fine. I ruined one of them and couldnt bring myself to buying another set of 4, when all i needed was one. The Lightspeed versions are sold by ACS and i ordered one.

It would not thread in properly. When i measured the eMag and Lightspeed versions, they were not the same...

I also can’t thread my differential compression tester into my engine with the adapter removed... so I’m guessing that the eMag ones have a geometry that are a little different and now the threads in my engine have changed slightly.
 
I quite often have to use a thread cleaner on the adapter and/or cyl so everything screws in by hand. If they don't go together easily somethings wrong.
 
I ended up using the Emag ones as the Pmag I ordered from Aerosport came as a kit with everything. They threaded in nicely by hand and everything seems to be working so far.
 
I’m getting ready to do an install of Pmags, do you still use copper gaskets?

Kevin
RV-10
KCXP
 
I quite often have to use a thread cleaner on the adapter and/or cyl so everything screws in by hand. If they don't go together easily somethings wrong.

Walt, what do you use to clean the threads? That’s ultimately what I’m looking to do.
 
I have used the Champion anti-seize as well. Has anyone found getting the spark plug out of the adapter difficult? Seems like it takes a lot of force and I definitely don’t over torque them when I put them in, I follow the emag directions. Also, I know they are called 14mm adapters but what is the thread on the inside of the adapter, e.g., m14 x 1.5?

I just changed plugs today and all of the adapters came out with the plugs. To get the plugs out of the adapters, I put a 7/8” deep socket with a hex on the bottom into a vice, then use a 5/8” deep socket to remove the plug. Keeps from damaging the adapters by putting them directly into the vice. :)
 
I just changed plugs today and all of the adapters came out with the plugs. To get the plugs out of the adapters, I put a 7/8” deep socket with a hex on the bottom into a vice, then use a 5/8” deep socket to remove the plug. Keeps from damaging the adapters by putting them directly into the vice. :)

I torqued the adapters to 20-25 lb-ft then put in the plugs at 15 lb-ft. Never had an adapter come out with the plug, and I have been pulling plugs annually for 18 years on 2 planes. Of course I use anti seize on both.

This is with the adapters Light Speed Engineering sells. I have heard of other makes of adapters breaking when torqued.
 
Sparkplug adapters

Fred,. these are the ones I am running.

18MM FLAT SEAT X 14MM FLAT SEAT (SHORT),

Just replace the included automotive crush spark plug washer with a copper washer.

Gary
 
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