Van's Air Force
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Auto plug guidance
- Thread starter s24789
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ChiefPilot
Well Known Member
The NGK BR8ES as recommended by Brad @ Emagair have worked great for me. I'm using them on both pmags without any issues at all. At $2.49 each, a complete set is less than a single aviation plug!
PN #3961
Agree on the BR8ES, but buy them by PN 3961 and you will get the solid top model, which may save you some of the high altitude miss grief like I had. Took me a while to discover the silicon grease in one plug boot had turned black, then I learned about the importance of getting the solid top.
BTW, gap with .032 safety wire, works well.
Tim
Agree on the BR8ES, but buy them by PN 3961 and you will get the solid top model, which may save you some of the high altitude miss grief like I had. Took me a while to discover the silicon grease in one plug boot had turned black, then I learned about the importance of getting the solid top.
BTW, gap with .032 safety wire, works well.
Tim
I also use NGK plugs in heat range 8 but they're 18mm plugs and require no adapter. Part number AB-8. IO-360 and dual PMags.
N941WR
Legacy Member
BR8ES's here too.
I replace them every condition inspection, cost for a set of eight is around $16.48.
Read their installation instructions and don't do anything different!
That includes grounding each P-mag to an independent case bolt close by. DO NOT bring them to a firewall mounted forest of tabs! I can't stress this enough.
When you are ready to time them, tie the MAP tubes together and time them at the same time with the same blow in the tube. (We have had clients who do them independently and have had different TDC marks set.)
For new engines or recently overhauled engines I recommend you install the "jumper" to force them to the "A" curve and plug the MAP lines (golf tee's work good for this.) so they don't advance. This will force them to act like a standard magneto. After 10 +/- hours, reinstall the MAP lines and fly it for about 50 hours before optionally removing the jumper.
Having debugged a number of installations due to our EICommander, you can only imagine how many different and unique installations people have come up with.
I replace them every condition inspection, cost for a set of eight is around $16.48.
Read their installation instructions and don't do anything different!
That includes grounding each P-mag to an independent case bolt close by. DO NOT bring them to a firewall mounted forest of tabs! I can't stress this enough.
When you are ready to time them, tie the MAP tubes together and time them at the same time with the same blow in the tube. (We have had clients who do them independently and have had different TDC marks set.)
For new engines or recently overhauled engines I recommend you install the "jumper" to force them to the "A" curve and plug the MAP lines (golf tee's work good for this.) so they don't advance. This will force them to act like a standard magneto. After 10 +/- hours, reinstall the MAP lines and fly it for about 50 hours before optionally removing the jumper.
Having debugged a number of installations due to our EICommander, you can only imagine how many different and unique installations people have come up with.
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N941WR
Legacy Member
I used that to slide the caps on the wires, that's it. I did use dielectric grease on the connectors though.
Don't get silicone on any surface that is to be painted. It is very difficult to remove and will keep paint from sticking.
Can you elaborate? If the case ground wire is connected to a forest of tabs on the firewall, what would be the issues with grounding each each P-mag at the forest of tabs? I've got 200 incident free hours with this configuration. Due to the criticality of an Ei system I have been thinking about adding a second ground strap between the case and the firewall.
Tks,
Mike
N941WR
Legacy Member
Simple, you are relying on only one ground path back to both of your ignitions, the grounding strap. While it does work and we have seen a number of people do this, the BEST practice is to ground them independently to a nearby case bolt as described in the P-mag manual.
Should that single ground strap fail or your forest of tabs fail (unbolt?), you could loose both ignitions. The idea is to have two completely redundant ignitions and ground paths.
In talking to Brad at E-mag Ignitions about this configuration, he did say that the P-mags may ground through their anodized case to the engine block but it is still best to ground them locally and to different bolts.
In the entire scheme of things, 200 hours isn't very long. You want a configuration that will hold up for thousands of hours.
Adding a second ground path between your engine and the firewall is a good idea but the truth is, you have it in your braided stainless steel fuel and oil pressure lines. Even with that in mind, you really want to ground your P-mags independently and to the engine case. After all, you are trying to keep your engine running, not your firewall.
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One ground only!
You want only one ground path from the engine to the airframe. If you were to use a ground from your PMAG to the firewall, there may(will?) come a day when that becomes a handy alternate path for your starter to ground. Smoke/fire....and there goes your PMAG ground path...or worse.
Tim
You want only one ground path from the engine to the airframe. If you were to use a ground from your PMAG to the firewall, there may(will?) come a day when that becomes a handy alternate path for your starter to ground. Smoke/fire....and there goes your PMAG ground path...or worse.
Tim
N941WR
Legacy Member
And there is that. Good explanation Tim!
ChiefPilot
Well Known Member
These aren't resistor plugs and therefore emit more RF than a resistor plug would. I considered these but decided against it but I am interested in hearing if you've encountered any RF issues?
A secondary factor was they were more expensive locally at $4.79 each but not dealing with the plug adapter might be worthwhile.
You didn't state what engine you have, and the compression ratio. High Compression Engines need a cooler heat range spark plug.
If you have a low compression engine (7:1) like an O-320 150 HP, you may like to try Autolite 386 plugs. These are resistor plugs, 18mm, so they don't use adapters, and several posters here on this site use them. They can be purchased for under $2 per plug.
I have 7:1 compression and use them with a Pmag. I don't have a lot of time on them yet, but for me, so far so good.
One poster (Doug Rosendahl?) reported power loss after take off with these plugs, and observed a burned plug tip. He stated his engine has 9.5:1 compression.
If you have a low compression engine (7:1) like an O-320 150 HP, you may like to try Autolite 386 plugs. These are resistor plugs, 18mm, so they don't use adapters, and several posters here on this site use them. They can be purchased for under $2 per plug.
I have 7:1 compression and use them with a Pmag. I don't have a lot of time on them yet, but for me, so far so good.
One poster (Doug Rosendahl?) reported power loss after take off with these plugs, and observed a burned plug tip. He stated his engine has 9.5:1 compression.
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Bill, Tim, much thanks for your input. Good reasoning and it simplifies wiring. I now have another Saturday morning project!
I cannot measure it but I have not observed any RF issues. I don't have any low-frequency equipment (e.g. ADF, HF, MB) or even VHF nav, only VHF comm. I'm uncertain whether the PMag supplied spark plug leads are resistive or not.
Yes, I spend about $40 for a set of plugs which is pretty much in the noise level for my aviation expenses (pun intended). I would be willing to pay a lot more not to deal with those adapters.
--
Joe
N941WR
Legacy Member
I don't get this? Those adapters are no big deal. Simply torque the sparkplugs down and the adaptors get torqued. When you remove the plugs, if the adapters come out with them, a second socket wrench removes them from the plug in two seconds.
There is the option of ordering jugs from ECi with the smaller holes so you never have to worry about adapters again.
rocketbob
Well Known Member
Pretty simple...why spend $150 for plug adapters if you don't need to.
deek
Well Known Member
I've gone through 3 sets of plug adaptors from LSE over the last 2,500 hours. I HATED to remove the top plugs/adaptors because something unpleasant invariably occurred. Klaus has changed configuration and/or materials several times but twice I've had the helicoil come out the head
I now use the same Denso L-14U (against Klaus' advice) with no issues.
N941WR
Legacy Member
You got me there!
The only problem I have ever had with the adapters was when I followed the advice of someone with a Light Speed Ignition who told me to install the adapters and torque them down and then install the spark plug, like Klaus recommends. I crushed the adapter and had to order a new one from Emag. Installing them on the plug, using anti-seize on both the plug & adapter, and then torqueing the plug, as Emag recommends has worked fine.I've gone through 3 sets of plug adaptors from LSE over the last 2,500 hours. I HATED to remove the top plugs/adaptors because something unpleasant invariably occurred. Klaus has changed configuration and/or materials several times but twice I've had the helicoil come out the head
I now use the same Denso L-14U (against Klaus' advice) with no issues.
N941WR
Legacy Member
Do NOT do this with inserts / adapters from Emag!!!
If you do, you will crush them. Just ask me how I know. (See my post at the top of this page.)
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N941WR
Legacy Member
It seams that Lightspeed and Emag get their inserts from different vendors.
When I tried to install my Emag adapters per Lightspeed's recommendation I crushed the first one and part of it almost fell into the cylinder.
This delayed some flying and almost forced me to pull a cylinder.
Since then, I have been installing per the P-mag Installation Manual and have not had any issues.
It is best to follow the manufacturer's recommendation, even when using parts that look to be very similar.
Toobuilder
Well Known Member
I had some bizarre PMag behavior last year (documented on this site) and finally traced it directly to the use of non resistor plugs. The non resistors would partially shut down the PMags in short order. Switching back to the recommended plug fixed the ignition immediately. It did this on four, count them, FOUR separate ignitions.
Non resistor plugs and PMags are bad juju. Period, dot!
Of course it was only AFTER I found this all out that I discovered the NGK warning about non resistor plugs and their potential to screw up electronic ignitions.
RV6_OKLA
Well Known Member
NKG Spark Plugs
Here is some interesting information on NGK plugs.
http://www.ngksparkplugs.com/tech_support/spark_plugs/index.asp?mode=nml
Provides a good understanding of how the spark plug choice affects the engine(plug fowling, overheating, compression, altitude, etc.). Of course this is regarding earth bound vehicles, but I can see the relationship with aircraft engines too.
I have dual P-mags on my 0-320 and use NGK BRE8ES plugs. They are so cheap that I replace them at conditional inspection even though they are in great condition.
Here is some interesting information on NGK plugs.
http://www.ngksparkplugs.com/tech_support/spark_plugs/index.asp?mode=nml
Provides a good understanding of how the spark plug choice affects the engine(plug fowling, overheating, compression, altitude, etc.). Of course this is regarding earth bound vehicles, but I can see the relationship with aircraft engines too.
I have dual P-mags on my 0-320 and use NGK BRE8ES plugs. They are so cheap that I replace them at conditional inspection even though they are in great condition.
Bob;
Thanks for the pic. Could you fill us in on the engine details, so we can objectively compare that spark plug?
What is your engine's displacement, compression ratio, and what cylinder head temp do you usually run? Do you tend to run near full power (I do) or idle around to save gas?
These would be the most important factors I can think of.
If you have 8.5:1 and run cylinder temps of 380F, a 7:1 engine that runs 320F Cylinder temps might be fine with the plug you show.
I am trying Autolite 386 plugs (on a P-mag), as Smokeyray had been using. That's an 18mm resistor plug. I have an O-290 with 7:1 compression and run cylinder temps of 320F most of the time (in my T-18). Perhaps any O-320, O-360 or O-540 with 7:1 pistons could use these 'hotter' Denso L14-U or Autolite 386 plugs.
The higher compression engines would need a colder plug than the one you show, and that's tough to find in an automotive 18mm resistor plug. These might require the cooler NGK BRE8ES, or other 14mm plugs and the adapters.
Thanks for the pic. Could you fill us in on the engine details, so we can objectively compare that spark plug?
What is your engine's displacement, compression ratio, and what cylinder head temp do you usually run? Do you tend to run near full power (I do
) or idle around to save gas?These would be the most important factors I can think of.
If you have 8.5:1 and run cylinder temps of 380F, a 7:1 engine that runs 320F Cylinder temps might be fine with the plug you show.
I am trying Autolite 386 plugs (on a P-mag), as Smokeyray had been using. That's an 18mm resistor plug. I have an O-290 with 7:1 compression and run cylinder temps of 320F most of the time (in my T-18). Perhaps any O-320, O-360 or O-540 with 7:1 pistons could use these 'hotter' Denso L14-U or Autolite 386 plugs.
The higher compression engines would need a colder plug than the one you show, and that's tough to find in an automotive 18mm resistor plug. These might require the cooler NGK BRE8ES, or other 14mm plugs and the adapters.
walkman
Well Known Member
As far as adapters go, they are the bees knees.
rcpaisley
Well Known Member
bronze vs brass
Aluminum bronze is a more brittle alloy. Naval brass has more malleability - better toughness.
We make our adapters in house on our Conquest 42 lathe. That's why we can afford to make them the best they can be In fact, we make all our mechanical parts in house. This is invaluable in achieving high quality, rapid product design and evolution, and providing the best parts possible.
In fact, we're running some spark plug adapters right now (pic below)
Robert
Aluminum bronze is a more brittle alloy. Naval brass has more malleability - better toughness.
We make our adapters in house on our Conquest 42 lathe. That's why we can afford to make them the best they can be
In fact, we make all our mechanical parts in house. This is invaluable in achieving high quality, rapid product design and evolution, and providing the best parts possible.In fact, we're running some spark plug adapters right now (pic below)
Robert
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Bob,
Are those plugs really as hot as this chart would seem to imply?
Thanks,
David
I did not see a reply on this important question regarding heat range of the various auto plug options that eliminate the adapters. From the chart above it appears that the Denso 14s are several steps hotter than the NGKk 8s.
Regardless of the successful use of the adapters by a number of people, I really do not want to add an extra set of threads into my combustion chambers.
I have researched heat ranges of the various plugs but have had a hard time finding a comparison of the auto plugs with the aviation variety.
Are the Autolite 386 plugs the same basic heat range as the Denso L-14U? And are they both essentially the same heat range as the NGK BR8ES plugs?
Randall, about to order Pmags...
Ghost two-six
Member
Sit rep
Guys,
It's been a little while, how have the auto plugs been holding up ?
Any issues with these plugs fouling due to avgas ?
Guys,
It's been a little while, how have the auto plugs been holding up ?
Any issues with these plugs fouling due to avgas ?
150 hours on a split install.
2 P-Mags with Tempest on bottom and NGK BR9-EIX Iridium (part No 3981) - CHT's ran a little high, but all was well.
Plugs installed as per Brad's instructions with no problems.
After 150 hours, we changed a few things.
New lower harness, swapped the airplane plugs for more NGK's, re timed the motor and had a good seal around the plenum. I know, we changed more than one thing, however, the CHT's came down by 50f !
We now have around 300 hours on the motor
TMX IO-360, 2 P-Mags, MT 3 blade c/s prop.
All well, temps great, plugs show no fouling on avgas, we get them either at O'Reilly's or Amazon for around $6 each. Swap them twice a year.
2 P-Mags with Tempest on bottom and NGK BR9-EIX Iridium (part No 3981) - CHT's ran a little high, but all was well.
Plugs installed as per Brad's instructions with no problems.
After 150 hours, we changed a few things.
New lower harness, swapped the airplane plugs for more NGK's, re timed the motor and had a good seal around the plenum. I know, we changed more than one thing, however, the CHT's came down by 50f !
We now have around 300 hours on the motor
TMX IO-360, 2 P-Mags, MT 3 blade c/s prop.
All well, temps great, plugs show no fouling on avgas, we get them either at O'Reilly's or Amazon for around $6 each. Swap them twice a year.
jbDC9
Well Known Member
I've been running dual Pmags with NGK BR8ES plugs on my RV-8 since day one; currently at 1150 hours and have had zero problems with the plugs. I run a mix of mogas (maybe 25%) in with 100LL, but have never had a fouled plug. I usually run a set of plugs for some 150-ish hours before replacement, which sets me back a whopping 2-3 bucks each at Autozone... nice.
WingsOnWheels
Well Known Member
Has anyone considered trying 12mm plugs with adapters. It seems that would leave more material for the adapter and reduce or eliminate any of the cracking issues?
I was working on my ignition harness yesterday and had dug out some old auto plugs to use for test fitting the harness while I worked on the wire routing. While digging through plugs I had on-hand, I cam across a leftover NGK plug from one of my motorcycles. it is a 12mm plug and it just got me thinking.
I was working on my ignition harness yesterday and had dug out some old auto plugs to use for test fitting the harness while I worked on the wire routing. While digging through plugs I had on-hand, I cam across a leftover NGK plug from one of my motorcycles. it is a 12mm plug and it just got me thinking.
