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PMags

mc607

Well Known Member
I will be ordering my new engine to avoid price increase. Can’t decide on Pmags. Can anyone tell me their experience. Pros and cons. What is minimum rpm to generate their own power? I’ll be going with the standard io390 210 h.p.
Fuel savings? Reliability?
Thanks
 
There are dozens (hundreds?) of threads on this with as many opinions.

Suffice to say that at this point any EI is a worthwhile upgrade from traditional mags and there are a lot of RVs with PMags.

Per the manual:

" ... the internal alternator will be unable to support the ignition somewhere below 900 rpm"

Reliable: Yes
Fuel Savings: Some
Easy: Yes
Worth It: Definitely

I started out with traditional mags and at 150 hours upgraded to dual PMags and have been very happy with them, easy starts and a smooth idle. Fair to say, there are other systems out there, each with their own pros and cons.

Note that unless something has changed, Lycoming will only ship with a single PMag and one traditional mag.

Edit: Regardless of how you order you can sell the traditional mag(s) (or the PMag if you want to use another system), they will move pretty quick if priced reasonably.
 
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Thanks for the reply. Have you tested yours to see what the rpm actually is when they stop producing power? What is your rpm setting on final?
 
Thanks for the reply. Have you tested yours to see what the rpm actually is when they stop producing power? What is your rpm setting on final?

Not scientifically, however, I understand that they can vary, 900 is the official safe spot. It's just not an issue, they don't draw much, so idling around the airport isn't really a factor or problem.

You aren't going to get below 900 rpm on final, even if you try.

While my power setting on final is "whatever it needs based on all the factors" I'm typically at 18 on downwind and 13 after I turn final then idle over the threshold (shooting for 70-75kts), but even at idle on final the wind through the prop still turns it north of 1000rpm, so the PMag generators are still running.
 
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Not scientifically, but mine is around 850, however, I understand that they can vary, 900 is the safe spot. It's just not an issue, they don't draw much, so idling around the airport isn't really a factor or problem.

You aren't going to get below 900 rpm on final, even if you try.

While my power setting on final is "whatever it needs based on all the factors" I'm typically at 18 on downwind and 13 after I turn final then idle over the threshold (shooting for 70-75kts), but even at idle on final the wind through the prop still turns it north of 1000rpm, so the PMag generators are still running.

Thanks. An EI that produces its own power, makes the most sense.
 
Thanks. An EI that produces its own power, makes the most sense.

I think the PMags are popular because they are the most "plug and play" install/retrofit with good general settings that suite most people.

However, if you want the ability to tweak and tune, there are lots of options.

Edit: When researching, note the dates of the threads. Some have formed (understandable) opinions on some of these systems based on problems that are ancient history.
 
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Personally not a fan of pmags on the angle valve engines, which includes the 390, due to the aggressive advance.
 
Personally not a fan of pmags on the angle valve engines, which includes the 390, due to the aggressive advance.

I do not agree. For either the parallel or angle head engines I recommend a maximum of 9 degrees advance. For the parallel valve engine this is 25 - 34 degree BTDC, for the angle head engines this is 20-29 degrees BTDC.

I installed dual pMags on an RV-14A with the IO-390 a few years ago. It is performing well.

Carl
 
I will be ordering my new engine to avoid price increase. Can’t decide on Pmags. Can anyone tell me their experience. Pros and cons. What is minimum rpm to generate their own power? I’ll be going with the standard io390 210 h.p.
Fuel savings? Reliability?
Thanks

Min RPM, ~900 rpm, tough to do in flight and ship’s power is the backup anyway.
Fuel savings? yes. I typically burn 7.3gph at 60-65% = 160KTAS cruise (RV7A 180hp parallel valve).
Reliability? Excellent. Two sources of independantly controlled ignition, each with two sources of electrical power, and only one moving part each. If you take the time to understand their operation, including how to properly setup, test, control, and identify their failure modes, there’s nothing better in my opinion except for turbine power. I fly over Coastal and Rocky Mountains ranges and large bodies of water. I would be more concerned with magnetos but that’s just me.
Customer service? Excellent!

Do you own research, make informed choices and move forward.

Bevan
 
A few years ago I bought the first airplane I’ve had in 30 years that I didn’t build. The smart guy that built my current mount had previously installed dual pmags after trying a combination of light speed and Slick ignitions, which he ultimately abandoned. Being a believer in mags, I procured a set of mags, harnesses, spacers, etc. in anticipation of just knowing that these pmags were not going to cut the mustard. Long story shortened, the pmags are staying, they are excellent. Starts quick and they help my little 165 hp io 320 run like a scalded rat. Btw, I have a set of mags for sale.
 
I do not agree. For either the parallel or angle head engines I recommend a maximum of 9 degrees advance. For the parallel valve engine this is 25 - 34 degree BTDC, for the angle head engines this is 20-29 degrees BTDC.

I installed dual pMags on an RV-14A with the IO-390 a few years ago. It is performing well.

Carl

And how did you go about setting that max advance, did you use the EI commander, pmag EICAD program or just retard 5deg on install with jumper in?

PS: If anyone has questions about pmag setup our old Bill Repucci is still around and is probably the most knowledgeable guy around on Pmags but unfortunately is not allowed to participate in the forums any longer.
 
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And how did you go about setting that advance? Did you use the EI commander or pmag program?
Just the pMag.
- Jumper in for both parallel and angle head engines. This caps advance at 9 degrees.
- Timing set at 25 degrees BTDC for parallel valve engines (this is done by setting the pMag timing with the crank at TDC)
- Timing set at 20 degrees BTDC for angle head engines (this is done by setting the pMag timing with the crank at 5 degrees ATDC).

Some people time with a degree or so less advance - builders choice.

Note - the new six cylinder pMags provides more control over the range of timing advance - as in more options other than the 9 degrees jumper in, 14 degrees jumper out of the four cylinder pMag. Even so, installing the six cylinder pMag on an IO-540 I stayed with the 25-34 degree timing curve. It has been flying for months now and has demonstrated a significant gain in cruise efficiency over the stock dual mag setup.

Carl
 
And just an FYI from the PMAG IM on this topic (I know most people don't like to read manuals):

E-MAG has NOT tested the myriad of fuel, compression, and engine configurations, and cannot prescribe which setting is appropriate for all situations.

 For most engines with recommended magneto timing of 25 degrees,
operators might start with JUMPER IN, and timed at TDC.

 For engines with recommended magneto timing of 20 degrees, operators
might start with both 1) JUMPER IN, and 2) CLOCK (time) the ignition 5
degrees after TDC.

 Different fuels, compression ratios, and other conditions may require
further adjustment.

IN ALL CASES, operators are responsible for determining proper settings.
 
I tested my pmags and found they self-power down to below 800 rpm.

However, I had an intermittent failure on my power to the pmags. I discovered the hard way that my rpm can fall below the self-power level while doing stall testing.

Not scientifically, however, I understand that they can vary, 900 is the official safe spot. It's just not an issue, they don't draw much, so idling around the airport isn't really a factor or problem.

You aren't going to get below 900 rpm on final, even if you try.

While my power setting on final is "whatever it needs based on all the factors" I'm typically at 18 on downwind and 13 after I turn final then idle over the threshold (shooting for 70-75kts), but even at idle on final the wind through the prop still turns it north of 1000rpm, so the PMag generators are still running.
 
If you're going to Osh you may want to stop by the forum to catch the below presentation, basically everything you always wanted to know about PMAGS/Ignitions:

Aircraft Ignition Basics
Thu, Jul 29, 2021 - Thu, Jul 29, 2021
11:30 AM - 12:45 PM
Location: Workshop Classroom C
Presenter: William Repucci
 
Just the pMag.
- Jumper in for both parallel and angle head engines. This caps advance at 9 degrees.
- Timing set at 25 degrees BTDC for parallel valve engines (this is done by setting the pMag timing with the crank at TDC)
- Timing set at 20 degrees BTDC for angle head engines (this is done by setting the pMag timing with the crank at 5 degrees ATDC).

Some people time with a degree or so less advance - builders choice.

Note - the new six cylinder pMags provides more control over the range of timing advance - as in more options other than the 9 degrees jumper in, 14 degrees jumper out of the four cylinder pMag. Even so, installing the six cylinder pMag on an IO-540 I stayed with the 25-34 degree timing curve. It has been flying for months now and has demonstrated a significant gain in cruise efficiency over the stock dual mag setup.

Carl

Copied and pasted from a PMAG guru:

Just the pMag.
- Jumper in for both parallel and angle head engines. This caps advance at 9 degrees.

All the jumper does is shift the curve, it does not cap it.* It moves timing from starting at 26.6 degrees with the jumper in to 30.8 degrees without the jumper, assuming they are timed to TDC.

- Timing set at 25 degrees BTDC for parallel valve engines (this is done by setting the pMag timing with the crank at TDC)

With the jumper, the timing starts at 26.6 degrees, almost 27 degrees, when set to TDC.* Too much advance for a standard parallel valve engine and WAY too much advance for an angle valve.
*
- Timing set at 20 degrees BTDC for angle head engines (this is done by setting the pMag timing with the crank at 5 degrees ATDC).

*
Not exactly, they really need to be set at 7 degrees ATDC to get them to fire at 20 degrees.* Even then, they will advance out to 30 degrees which is way too much advance for an angle valve engine.

Want to know more, attend the seminar at Osh or contact Bill R.
 
So this choice shown below on the Van's engine page means you get one emag and one magneto installed?

o Replace plain magneto with e-mag + $1,200.00

Thanks
Chris Lucas
RV-14A
#140666
(RV-10 bought by Florence)
 
Or like I did on the last engine I ordered:
- One pMag
- The other hole covered - nothing in it - credit for the mag that was removed. Don’t forget to ask for the mag gear. They should give that to you for free as it is an engine part (they did for me). They are pricey.

Once the engine showed up and mounted, I added the second pMag.

Carl
 
Ok thanks, sounds like a plan. About to hit the SUBMIT button. That actually sounds about right... submit!
-Chris
 
P-mag

So this choice shown below on the Van's engine page means you get one emag and one magneto installed?

o Replace plain magneto with e-mag + $1,200.00

Thanks
Chris Lucas
RV-14A
#140666
(RV-10 bought by Florence)

Yes. Due to liability, they won't replace both. However, it's simple to swap them. However, new (unused) Mags have value. You might consider ordering with mags, buying two P-mags, installing then selling the two mags. I don't know the exact figures but you may be better off.
Two new P-mags are about $2800
Two new mags sell for about $2000. Maybe more. You will need a gear for the Impulse side. The Impulse gear can't be swapped to the P-mag.
The downside is swapping on a new engine may effect warranty.
I could be way off. It's been a while.
 
FWIW, when I ordered my Thunderbolt engine in early May (so glad I got in the queue before the price rise), I selected the 1 E-Mag & delete second Mag option. After the order got to Lycoming, I was contacted by them confirming paint colours and asking if I wanted the 2 E-mag option. I took this option, Van's were notified by Lycoming and I had a revised Order Acknowledgement sent showing "EA TB DUAL E MAG - Dual P Mags for Thunderbolt".
 
Hmm, I'll go ahead and put a note in the note box and ask for another emag and see what happens. That sounds encouraging because I am going Thunderbolt too.

Thanks
Chris
 
Ordered the YIO-390-EXP119 last night. Available engine configurations: dual magnetos, dual Lycoming EIS, or dual P-Mags.
 
The order form for the standard Lycoming now has the dual P-Mag option - at least for the YIO-320. Here’s a snip from my order confirmation.
 

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Dual Surefly (Lyco EIS)

I ordered as well because of the inflation hike. Chose dual Surefly. I'm so excited to get electronic ignition! If I had a nickel for every mag issue I've had over the years... Well, I wouldn't have that many nickels, but I'm still excited about electronic ignition. :D
 
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