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Old 01-12-2012, 03:37 PM
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Ironflight Ironflight is offline
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Location: Dayton, NV
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Default Out with the Old, In with the New ? Upgrading to P-Mags

Seven or eight years ago, when I was buying equipment for my RV-8 project, I was intrigued by the (then) new E-mag electronic ignition. Intended as a nearly “drop in” replacement for regular magnetos, I sure liked the clean design that did not require a separate “brain box”, crankshaft sensor, or extensive wiring. It seemed to me to be a great design concept – but I’ll be honest, I was a little nervous about anything that absolutely MUST work (to keep the airplane in the air) being that new. I decided to equip the airplane with tried and true Slick mags, and keep an eye on the E-mags. I watched as numerous people went with one, then two of the units, as well as the even newer P-Mag – an E-mag that had its own internal alternator so that once it was going, it was independent of ships power to keep the engine running. This really upped the interest, since it was pretty much as electrically independent as a traditional mag (except for starting – and take-offs are almost always optional).

After some early teething problems with temperatures and mechanical components, it appeared that folks who I have a lot of respect for were piling up hours on their P-Mag installations. Reports of difficulties became few and far between, and reports of improved customer service on the part of Emagair went up. I saw both of these as positive signs, so when it came time to have an engine built for our new RV-3, we pulled the trigger and went dual P-Mags to get the maximum benefit of EI all the time.

With 1430 hours on the RV-8’s engine, we suffered our first real Slick mag issue (I have had great luck with Slicks on a number of airplanes) when the left mag died on a long cross-country. Most likely a coil issue, we were able to borrow a mag from a friendly mechanic to get home, and then I started shopping for a pair of new Slicks. The price of coils and overhaul parts are such that it really makes about as much sense to buy a new one as it does to fix one that is malfunctioning, so I was looking at about $1600 for a set. P-Mags would cost more, but if I was ever going to make the switch, now was the time – and since I was committed (and happy) on the RV-3, I figured why not go ahead and bring the Valkyrie’s engine up to the same standard.

At the same time, it would allow me to see (and share) first-hand what was involved in making the swap. It turned out to be very straightforward and simple, with the greatest time spent in adding a couple of circuit breakers and determining where I wanted to run the wiring to supply ship’s power to the P-Mags. As always, making the installation look pretty takes a little extra time as well, but overall, this was a weekend project (if you don’t count the days I spent waiting on a couple of special parts and tools for my unique installation.

Find an Album of Pictures (with captions) here:

I have been really impressed with the quick and easy starting on our RV-3, but I had nothing to compare it to - it came with P-Mags - so it has always started quickly. With the -8, I could get a direct comparison to the old Slicks – and it was like night and day. First off, I have always considered this to be a very nice-starting engine. Now, I was surprised at just how quick it lit off – like the proverbial one or two blades. Second, I have always had pilot passengers remark on how smooth the engine runs – with Mags. I was SHOCKED at how smooth it now started and idled with P-Mags, right out of the box. The ignition is obviously hotter and more powerful, and doesn’t misfire a single cylinder. After a little running on the ground, I cowled it back up and took it for a quick flight around the pattern. Leaning was incredible – even with a carburetor, you can lean it way, way down into the LOP region without misfiring – and I mean down to where the power is dropping off dramatically (but smoothly). It is going to be possible to run quite a bit leaner than before, and I was always able to run 50 LOP without a problem

Easy installation, a reasonable cost (when compared to a full-up Slick system), and few reported problems in the latest installations – I am sold. I fly lots of cross-countries, and cover lots of ground where I’d rather not land – but I am comfortable now that these have reached a level of maturity that I can trust. True – if I find myself with a dead P-Mag, I probably won’t find one on the field to get me home (like I might with an old Slick), but Fed Ex can reach us just about anywhere these days, and I won’t stuck for very long. Everything is a compromise, and you might find yourself stuck with a dead mag (and no replacement) at some out of the way refueling stop as well. But the past few years of demonstrated reliability, plus the smooth starts and potential for efficiency finally tipped the scales for us. We still have one Slick-equipped airplane, and when it needs ignition work, we’ll see what makes the most sense – but the P-Mags seem to be an easy and sensible direct replacement if you are looking at buying two new mags anyway.

And the installation? Piece of cake!
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)

Last edited by Ironflight : 01-12-2012 at 07:55 PM.
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Old 01-12-2012, 03:40 PM
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Ironflight Ironflight is offline
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Default Notes

So here are a few notes to outline the project – one that even a non-builder should have no trouble following!

1) Pulling the old ignition was a piece of cake – the only things that are remarkable is that the hold-down studs for the left mag will most likely be too long for the P-Mags, since that mag usually has an impulse coupler, which requires a spacer – which requires longer studs. You’ll remove the spacer to install the P-Mag, and will probably want the shorter studs. Pulling the longer studs was easy with a special (expensive) Snap-On tool:

2) The P-Mags (like other mags) do not come with drive gears – they are engine parts. You can remove and re-use the one from the right mag, but the impulse-coupled mag has a different gear. Emagair was able to supply me with the correct gear (it was marked “used”, but looked great!) and that (to me) was an easy way to go.

3) The automotive ignition wires used by P-Mag are slightly larger in diameter than the aviation harness wire, so you’ll need some larger Adel clamps as replacements. Aside from that, everything is in the box with the P-mags – including a bag of microwave popcorn to keep you occupied while reading the manual.

4) Although I originally wanted aviation plugs just because I was comfortable with them, Brad (at Emagair) convinced me that not only were the automotive plug wires a much better fit (they are – the aviation caps are sort of Mickey Mouse, and he admits that), but the ignition was really designed to use auto plugs.

5) Installing the P-mags themselves took no time – and it was really nice to be able to orient them the way I wanted – with the side for the wiring harness plug facing outboard on the engine – this makes hooking things up and doing maintenance down the road SO much easier!

6) Attaching the power and control wires is pretty simple. If you decide to pick off the tach signal, you’ll have four wires to a P-Mag – Power, ground, the ignition switch “P-Lead”, and a Tach wire. While some have complained about the type of connector used on the P-Mag, I found that they were fairly simple to use, and look robust IF you follow instructions and use the supplied Adel clamp to restrain the wire bundle properly.

7) I supplied power to the two mags through separate 3 Amp circuit breakers that I added to the cockpit, and powered from my essential bus. Since the P-Mags will generate their own power once the engine is running more than 800 RPM, I was satisfied with a single power feed to each – considering that I have two different batteries and two alternators as a way to feed the essential bus. And if the airplane is really “dead-dead” when I go to start, I probably need to fix that before I go flying anyways.

8) You’ll have to look up the recommended connections for your particular tach (or EFIS) to see what it is expecting. In my case, I am using a Grand Rapids Technologies EIS – 4000 to collect the tach signal and feed it to my GRT EFIS. To hook it up to the old Slicks, it needed an inline resistor to work properly. Fortunately, I had planned ahead for a day like this, and put the resistor in with spade connectors – so it was a simple matter of pulling that out, and substituting a short wire with the appropriate lugs in it’s place. This took almost no time – but since I had an older EIS, I also had to go in to the box (using an excellent instruction sheet supplied by GRT) and clip two components – (a resistor and a capacitor) off of a circuit board. This took about ten minutes.

9) One other quick task was the addition of some cooling blast tubes – I have never used them for Mags (although many do – and if you do, then that job is done). P-Mag instructions specify blast tubes to cool the round “neck” portion of the units, and since they had early problems with temperatures, I think it is very wise to follow their instructions here.

10) The last thing I needed to do to hook things up was to add a manifold-pressure line to the two P-mags. The easiest way to do this is to route the two lines from the P-mags to a static-line Quick Disconnect “Y”-fitting. From there, a single line can be routed to a transducer manifold, or to a “T” in your manifold pressure sense line. Because of the way I had routed the lines on my RV-8, it was easier to add a “T” in the line going to the manifold pressure sensor, and secure the “T” to the engine mount. I really like having the QD in the sense line, because you set the timing with a blow into the hose – and you can pop it off quickly to accomplish this.

11) Timing was the easiest part. Set the prop at TDC (NOT 25 before TDC!!) – any cylinder, just line up the TDC mark on the starter alignment hole, or the seam case (which ever you have easy access to). Once there, power up the P-Mags with the ignition switch “off”. See the red lights? Blow in the tube until the lights blink, then blow again to confirm – and the lights turn green. BLOW HARD – it takes a little bit of pressure! Reconnect the line, and you’re done. An inspection mirror helps to see the LED’s – one will be easy, one will be tougher to get to.
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)

Last edited by Ironflight : 01-12-2012 at 08:02 PM. Reason: Typos!
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Old 01-12-2012, 04:24 PM
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islandmonkey islandmonkey is offline
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Excellent report. I have book marked this one and it should go into the "Tips" section IMHO.
Anthony Johnston
Brit working in Zurich, Switzerland.
1500 hour pilot and ex instructor and examiner.
RV-4 s/n 4572 Emp Kit.
RV-3B s/n 11460 Emp Kit. (In storage).
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Old 01-12-2012, 07:00 PM
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panhandler1956 panhandler1956 is offline
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Location: Ohio
Posts: 1,686
Default Nice write up

Great to see the -8 isn't suffering from the 'new-kid-on-the-block' syndrome! I too have been curious about P-mags and my budget didn't allow it first go around, but a set of these is definitely on my wish list...
Thanks for sharing your experience both on the installation and operation!
Brent Owens
EAA Chapter 9 Tech Counselor/Flight Advisor
Columbus, OH
RV-8 'Contrary Mary' flying
N784DE S/N #82614
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Old 01-12-2012, 08:28 PM
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CharlieWaffles CharlieWaffles is offline
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Location: West Linn, Oregon
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Love the popcorn bag included. Its the small things sometimes that really makes it easy to connect with a company. Now they just need to get their 6-cylinder product to market!
CharlieWaffles - But you can call me "Mark"
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Old 01-12-2012, 08:31 PM
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DanBaier DanBaier is offline
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Location: Rochester NY
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Paul -

Anything noticeable (or even imaginable) in the power department?

RV7A (N7101) - Flying 10/2008
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Old 01-12-2012, 08:41 PM
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frankh frankh is offline
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Location: Corvallis Oregon
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Default This can be tough

Originally Posted by Ironflight View Post
So here are a few notes to outline the project ? one that even a non-builder should have no trouble following!

Pulling the longer studs was easy with a special (expensive) Snap-On tool:

The old standby of two locking nuts was not sufficient to overcome the incredibly sticky stuff that holds the studs in.

When the nuts started moving I picked up the mig welder and welded the top nut to the stud..then used a standard 6 sided socket.

I have used this trick many times and it works when other methods fail.

You have to have a mig welder handy of course.

Other folks have got them out sing vice grips..incredibly slow though.

A very nice write up Paul.

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Old 01-12-2012, 09:41 PM
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logansc logansc is offline
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Posts: 571

In your conversations with Emagair, did they happen to mention which year they would come out with their 6-cylinder system? Us Rocket guys have been waiting a long time. One more annual---and I'm going for another brand!

Thanks for the info on your swapout...

Lee Logan
Ridgeland, SC (3J1)
F1 Rocket #160 flying
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Old 01-12-2012, 09:45 PM
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rv6rick rv6rick is offline
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Location: Chesapeake Bay
Posts: 747

Hi Paul,

I've never been a fan of the P mags...but time has gone by. Thank you for taking the time to share your experence. After reading your post I vow to consider this set up next time around. Well done and thanks again.
Rick Gray on the Chesapeake Bay - Builder Assist Center - 50+ Awards & counting


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Old 01-12-2012, 10:57 PM
paul330 paul330 is offline
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Originally Posted by logansc View Post
In your conversations with Emagair, did they happen to mention which year they would come out with their 6-cylinder system?
My IO540 is on delivery from AeroSport. I had hoped to have it shipped with the P200 but STILL not available. According to Aerosport, it is in Beta testing and should be out this month. Having said that, it was going to be last spring, summer, fall.........

Sorry, Paul - bit off subject. Nice job and excellent write up!
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