P-Mag Operating Temperatures

[Toobuilder]

Originally Posted by FasGlas

This may take a little work to compile and post pics and data. The forum only allows a few pics to be linked to a post. I have many pics of my EI Commander showing all the anomalies of my pmags.

Do those anomolies correspond with engine performance problems? In other words, if you did not have the EI Commander, would you notice any problems? Is this simply a matter of having "too much" information to study, similar to the fantastic amount of data supplied by current engine monitors - and the recent focus on exact EGT, CHT, and related perameters that in past decades we would blissfully ignore?

As one more data point, I have several summers worth of desert flying (including a take off on a 121 degree day) with no issues on my 113 series Pmags. Just a simple 5/8 inch blast tube aimed at the neck of the alternator.

[GalinHdz]

FWIW I have 180hrs, and counting, on dual P-mags with no problems whatsoever. I also have a simple 5/8" blast tube aimed at the P-mag necks.

[N941WR]

Originally Posted by Toobuilder

Do those anomolies correspond with engine performance problems? In other words, if you did not have the EI Commander, would you notice any problems?...

I'll answer this for Randy.

For the most part you are correct; however, Randy purchased a used set of 114 P-mags which were never "right" from the factory.

He recently replaced the board on one P-mag board and that solved most of his issues.

One thing the EICommander can do is tell you if the ignitions are firing at the same time. When we designed the EIC, we ran into issues when the RPM dropped below 500 RPM, so thinking no one would run below ~650 RPM +/- the Timing alarms are somewhat unpredictable down below 500 and because of the airplane he is flying, he has his RPM set in the high 300 RPM range. (I had no idea a Lycoming could turn that slow.) This low RPM, coupled with the averaging routine in the EIC makes it look like he has a timing issue; however, when he powers up for flight, the ECI report correctly and his timing divergence alarms go away.


The following are some general comments regarding P-mag operations and configuration, not necessarily related to Randy's issue(s):
The EICommander is a very sensitive instrument and we have done our best to eliminate false alarms, thus there is a pretty sophisticated averaging routine in our code and it will not alarm until we know there is an issue.

Here is a short list of things we have found that can impact the P-mags but you would never know, unless you have an EIC:
1. Setting the timing in one P-mag and then the other. (Solution: blow in the tube and set both TDC marks with the same breath. Don't ask me why, but it has been an issue.)
2. Ground the P-mags to the engine case bolt, not the forest of tabs and run a second wire from the P-mag directly to the EIC, not a forest of tabs. The EIC can pick up odd signals from other electronics on the ground bus.
3. Run the tach wires from the P-mag to the EIC and a second set of wires from the P-mags to your EFIS. Although they connect at the P-mag, separate wires seem to be important.
4. Install a good pressure stabilizer in the MAP line.
5. Make sure you have good quality mag gears installed on the P-mags. (Emag used to sell gears that were not properly case hardened and have been know to wear prematurely.)

The list goes on but most things are fairly simple to do and are good building practices.

Even with #5, the only way the pilot knew there was an issue was because of the ECI's Timing Divergence Alarm function. The coil pack data display has found a number of bad plugs, bad wires, coil packs, fouled plugs, etc.

While you do not need an EIC to fly with the P-mags, we appreciate Randy's confidence in our instrument. A number of our clients now insist that they will not fly without P-mags and the EIC. Think of it this way, most will not fly without a full EMS to display the health of their engine. The EIC is an EMS for your ignition.

If any of you have questions about your set up, feel free to contact me.

As far as known issues:
I have worked with a number of people with P-mags (with and without the EICommander) and apparently have found far fewer problems than Randy has eluded to. Granted, the early 113's had problems with trigger magnets falling off (since fixed) and software issues (since fixed). And there is the occasional hardware failure issues (Heck, we have even seen that with the EICommander and strive to improve our product and resolve customer issues quickly.), but for the most part, I believe they are proving themselves more reliable than standard magnetos.

For those of you who have not followed the issues, this thread should give you a pretty good idea of best practices with P-mags.

[Walt]

What exactly is this?

"4. Install a good pressure stabilizer in the MAP line".

I suspect most folks just tap into the MP line.

[Toobuilder]

Originally Posted by N941WR

...For the most part you are correct; however, Randy purchased a used set of 113 P-mags which were never "right" from the factory...

Please understand that I was asking a question, not making an assertion.

Anyway, The question was rooted in determining if the anomalies were "caused" by information overload, or if there was a legitimate issue with his particular configuration. I'll take anyone at their word that they have experienced problems - there were a few in the early days that could not make Pmags work despite heroic efforts by Brad and company - but when those people make a blanket statement that Pmags in general (i.e. as a product line) are "unreliable", then we need to dig deeper. Maybe it is the individual installation that is the cause? Particularly when many of us have had stellar service from our Pmags. And I do have a good friend who is one of the very early adopters of the Pmag AND EI Commander and has no issue flying his Glassair in "hard" IMC. He has not seen these issues either. The only issues I've had were self induced when I used non-resistor plugs.

So it still is a question whether these issues are a result of TMI (over analysis), highly isolated/self induced, or as posted in #23 and #27 - widespread.

[N941WR]

Originally Posted by Walt

What exactly is this?

"4. Install a good pressure stabilizer in the MAP line".

I suspect most folks just tap into the MP line.

That can be good and bad. Some modern EFIS's "smooth" the MAP indicators, even though the actual pressure is bouncing all around.

It really takes a restrictor, up stream of the P-mag MAP line, to give good, consistent readings for the P-mags.

[FasGlas]

OK!! HOLD THE PHONE HERE!!!

I have never bought a set of 113 pmags. I bought a pair of 114 ver 36 pmags and an EI Commander from a guy that bought this all, installed them, the pmags didn't work, they were sent back to emag, returned and still didn't work. They were removed and I started to work with them. This i where I came into this story.

I installed them with the EIC. I took them out flying and the first thing I noticed was the extremely hot CHT's. I ran the timing back and got the CHT's down to a tolerable level. Next the timing on the pmags started jumping all over the place. I sent them back to emag where they sat for 5 weeks, then returned to me in the exact same shape. I was supplied with an old used replacement board (guess I'm supposed to fix them myself). I replaced the board on the left pmag and the left timing stopped jumping. Now on to the right pmag. I took it apart and cleaned out the body and sprayed down the board and connectors, reinstalled it and retimed them, at this point they both seemed to hold the timing. I put some hours on them and learned to live with the best they could do, high CHT's and not much added power.

Next I fly from SoCal to OSH. On the way there and back (18.2 hours total) the EIC would display as much as 10 + degrees timing between pmags, or XXXX's on the left pmag, or large TDA's (timing differences between the pmags) for hours at a time.

I contacted the designer of the EI Commander, we've been in contact for the last 2 years trying to solve these problems. He sends me a new EIC, and of course that wasn't the problem, never has been. So I relay all this data to Brad at Emag. He has no idea what the problems are, again. Of course I get the "check the hoses, check the wiring, check the mag gear, etc, etc." All this was done over and over.

Brad sends me an old pmag with an updated board, ver 40. I installed the ver 40 board in my left pmag, as we all agreed that the left pmag has a data problem. I retime them both and go flying. First thing I see is this huge TDA at lower RPM's. NOT 500 RPM but as high as 1600 RPM! As the engine wound up the TDA's went to normal 2.0, which is the minimum readout.

Again, Ed at EIC sent me another Commander (Best service in the biz) which I knew wasn't the problem, but we tried it anyway.. It wasn't the problem. At this point I had Ed, Bill, Brad and myself running one test after another to see if these anomalies could be traced down. Test after test showed that there was nothing causing this TDA problem other than the pmags. The only difference between the pmags at this point are the board revisions and the software versions. Brad doesn't seem to be concerned enough to help me find the problem. I've asked him to send me matching boards to eliminate the Rev and Ver differences but he doesn't want to. He told me to "Turn off the EIC".

I've been in electronics my whole life, along with being an A&P, a instrument rated pilot since 1980, building Exp aircraft for 12 years and OSH gold. One thing I've learned in all my experience is that any electronic or mechanical problem is most always the beginning of other problems, systemic, like cancer. These 2 pmags have never worked properly since the day they were built. The EIC proves this and my EMS proves this. Whether or not the pmags are firing the plugs does not prove that the pmags are working properly. The last place I want to find the next pmag problem is at 2K feet over the mountains.

I have documented all these EIC readings and EMS graphs, there is no denying these are real and continuous.

I have received PM's on this forum and other forums telling me story after story of pmag failures. As we all know, most people do not like to post on the threads but they want their story to be known. Since I've been outspoken about pmag problems I guess people what me to know what happened to them, too. I fly with other pmag owners and I've seen the same failures and timing shifts. I've installed many pmags and they run. BUT!! The difference between most of these installed pmags and my pmags is I have an EI Commander to monitor what's actually going on, not what other people tell me.

I would no sooner turn off my pmag monitor as I would turn off my engine monitor. You monitor your plane for a reason. These are Vitals. Would anyone fly if they knew number 1 cylinder was 250 degs CHT and number 3 was 500 degs CHT? Why not just turn off the engine monitor and be a mushroom. You have monitors to find small problems before there's a meltdown. If you see nothing wrong you're a happy pilot.

BILL... IF YOU'RE GOING TO TELL MY STORY PLEASE GET YOUR FACTS STRAIGHT!!

If anyone is flying with pmags and no way to monitor what they are really doing than you have no idea what's going on. Just because you're plugs are sparking doesn't tell the whole story. Just because you don't smell burnt oil doesn't mean your engine isn't about to grenade. Just because you don't see the cracks doesn't mean the tail isn't about to come off in the air. We have monitors, and preflight monitors, our eyes, to find problems.

No one using pmags, or any other EI, can tell me they work perfectly just because the engine starts and runs. How do you really know!!

[AX-O]

Originally Posted by FasGlas

This may take a little work to compile and post pics and data. The forum only allows a few pics to be linked to a post. I have many pics of my EI Commander showing all the anomalies of my pmags.

Then load the pics up in Picasa and post a link on VAF. I am also interested in knowing what all these failures are. Thank you.

[Toobuilder]

Originally Posted by FasGlas

...No one using pmags, or any other EI, can tell me they work perfectly just because the engine starts and runs. How do you really know!!

That's a perfectly valid point, but that premise applies to magnetos, alternators, vacuum pumps, autopilot servos, etc.

Information is powerful, but it needs to be tempered with an end result - does the airplane complete its mission safely and reliably?

[N941WR]

Randy,

I added a bold header to separate my comments about your issues from my general comments regarding P-mag installations. Also corrected the 113 vs. 114. When we spoke, I thought you started with 113's, my mistake.

I realized when I re-read it, it sounds like that entire post is about you and what you have found and that is not the case.