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Dual P-MAG Reliability in 2017

RhinoDrvr

Well Known Member
Hello all,

So the RV-8 I just purchased has the LASAR ignition system, and unfortunately the slick mags it uses are just about to the point where they need to be overhauled. Instead of paying to overhaul the one off mags, I?m debating replacing the LASAR system. I?ve priced out 3 options.

2 Slick Mags - $2500
2 P-MAG?s - $3200
G3I Ignition - $4600

The airplane currently has an auxiliary battery, but I like an ignition that isn?t reliant on ships power, so those are my 3 options.

I like the idea of the P-MAG?s the best, but have been unable to on find any data on reliability of the new, v40 firmware, latest version of the hardware P-MAG?s. I also think the P-MAG would be the most straightforward install given the LASAR setup I would be removing already has a Manifold Pressure Line etc.

What are your thoughts?
 
We went through this same thing here a couple of weeks ago. As usual, a long thread.... search for Pmag.
 
I had two PMAGs in my RV7A and I was running v40 which ran flawlessly for the 150 hours that I had installed the PMAGs. The installation and timing of PMAG is super easy. I saw about a gallon of fuel saving (for the same speed) up high and about .8 of a gallon of saving when I had only one PMAG.

I definitely recommend it.
 
Pmags

Been running dual p-mags since first flight in 2008, flawless performance, would definately do the same again.
 
We went through this same thing here a couple of weeks ago. As usual, a long thread.... search for Pmag.

I did a search, but wasn't able to find a good quantity of data from 2017. Most posts are with issues that folks were having in 2012-2015. My main curiosity is if all the teething issues with the P-MAG's have been fixed and if the system is reliable enough to use without a backup system in place other than an auxiliary battery.
 
Like any thing else, a few units will suffer infant mortality, but for the most part, they are bullet proof.

Just make sure to install them per the manual.

Depending on the engine you are running, you may have to tune them to match the manufacturer's recommended timing. This is fairly easy to do.

Check your email.
 
You have a second battery already?

No contest: SDS CPI

This sounds really dumb, but....

The control panel is hideous and I don't want it on my panel. If it could be integrated into a panel that looked more like something that belonged in an airplane I would be more interested.

The airplane currently has a really neat, well laid out steam gauge IFR panel, and I don't want to ruin that with the incredible hulk of engine monitors.
 
Indeed the current gen CPI brains are "unsightly", but there is no need to have them in the panel. They can be hidden once programmed.
 
...They can be hidden once programmed.

And that is one of the issues with this system, it has to be programmed, and my experience with helping with probably 100+ P-mags installations, I have come to realize that most builders don't understand ignition timing.

With the P-mags, they can be installed, and run. No need for battery backups, multiple components, etc. Once installed, they just work. They can be tuned for specific installations, if needed.

Now back to the OP's question about P-mag reliability...
 
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... and my experience with helping with probably 100+ P-mags installations, I have come to realize that most builders don't understand ignition timing...

...and many of us have come to realize that P-mag (the company) doesnt understand ignition timing either.

But unlike the company, builders have the capability to learn. After all, we trust mere pilots with a mixture knob, right?
 
...and many of us have come to realize that P-mag (the company) doesnt understand ignition timing either.

But unlike the company, builders have the capability to learn. After all, we trust mere pilots with a mixture knob, right?

I read the chart that compares different ignition system and have failed to see the advantages of the CPI over PMAG, perhaps other than programmability. This maybe simply due to my lack of knowledge on the subject matter and it is not based on prejudice

One difference that has been noted, is the ability to custom program the timing on the CPI which to some degree is possible with PMAG. Is this the main advantage of the CPI system as I am looking at choices and advantages of different system for my new plane. Also realistically, how many people program the timing wildly different. I had installed a EICommander in my old plane and end up with the standard curve A which seemed to be the best suited.
 
...and many of us have come to realize that P-mag (the company) doesnt understand ignition timing either. SNIP

A bold statement not supported by the hundreds of pMags now flying - nor my personal experience. If you are referring to recent articles on the subject, any timing curve and be optimized for whatever conditions you want. Most of us want overall performance.

If you want timing to just run flat out full power, stay with a mag and fixed timing. If you want efficient cruise with years of demonstrated performace, get pMags. If you must fiddle with timing while flying, then go another path.

Carl
 
A bold statement not supported by the hundreds of pMags now flying - nor my personal experience. If you are referring to recent articles on the subject, any timing curve and be optimized for whatever conditions you want...

I was a satisfied P-mag driver for many years, and then I tried CPI. Does your personal experience include flight test, or even ownership experience of the two ignitions? If not, then all I can say is you dont know what you dont know.

P-mags are good... CPI is GREAT!


...If you want timing to just run flat out full power, stay with a mag and fixed timing...

Nope. Not true either, based on actual flight test experience.
 
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Dual P-Mags on a Lycoming O360-A4M since 2013 (over 300hrs) and love them. Taking into account all variables , I would not use any other ignition system. My 2 cents.

:cool:
 
I read the chart that compares different ignition system and have failed to see the advantages of the CPI over PMAG, perhaps other than programmability. This maybe simply due to my lack of knowledge on the subject matter and it is not based on prejudice

One difference that has been noted, is the ability to custom program the timing on the CPI which to some degree is possible with PMAG. Is this the main advantage of the CPI system as I am looking at choices and advantages of different system for my new plane. Also realistically, how many people program the timing wildly different. I had installed a EICommander in my old plane and end up with the standard curve A which seemed to be the best suited.

Hard to find an advantage from that chart. Its just data. About the only thing that really stands out as data is the price advantage to CPI.

The ability to custom program the CPI flies right over the heads of many potential customers because they "trust" that all of these manufacturers have done their homework and come up with an optimal curve. As we have seen time and time again, this is not the case. Are the existing curves melting down engines? Nope, but are they right? Nope. P-mags have been in the spotlight lately and since you and I are both users of P-mags, I can tell you that their curve is generally too aggressive at high power and may not be enough at the high LOP area. Sure you can shift the curve up or down with the EIC or Bill's product, but you can't fix the basic flaw in the slope of the curve. What this means to the customer is that if you want the right timing at high power for detonation margin, and the right timing for LOP cruise you have to get CPI. P-mag simply does not have the breadth to be optimized for your whole profile. It may be "good enough" for some, but so are 172's.

And do people radically alter ther timing from application to application? Not my experience. The high compression guys shift the whole curve down a few notches, but the basic programming is a no brainer. The curve that I developed last year has been passed around to a bunch of people and it works great as a baseline.

Another thing not apparent on the chart: P-mags require regular inspection including removal from the engine. Is it hard? No, but certainly more than the ZERO maintenance CPI requires. Once CPI is installed you dont ever have to touch it again.
 
1200+ hours with two Pmags

I like them. I started with traditional mags, switched to one Pmag after 300 hours, then swapped the second out after another 100. Now, with over 1600 hours, I have quite a bit of time evaluating them.

The early issues that were uncovered as the number in the field increased have been addressed with minor modifications and a few program updates. Rather than adding timing features they have chosen to keep the product stable with reliability focused updates. I use the windows EICAD program with a laptop to adjust the parameters but it would be nice to have more options for managing the advance.

One of my old units had started to give an occasional 'magnet out of range error' that prompted my need to get a replacement in hand in a bit of a scramble right before Reno...

Comparing the new one to the old ones... most notably, both of the old units have developed quite a bit of shaft play. I look forward to seeing what the serviced unit looks like when it makes its way back shortly.

I have had an an occasional (perhaps four times) boot up failure that is reportedly addressed with v40+ firmware. Each time it was resolved by shutting down and re-timing.

One coil pack developed a dead post... I received a replacement.

Much later, one coil pack, on two posts, started arcing a bit with the plug wires... this eventually led to an intermittent spark. I suspect that the root issue was a combination of a lack of dielectric paste and a loose attachment. After replacing the plugs, wires, and cleaning the posts it all worked fine. I use dielectric grease now and ensure that the plug end is firmly attaching to the post.

I have spent quite a bit of time with the advance in search of any top end speed... my advance is set at -4.2
 
I don't understand why someone asks for data from actual users of a product has his thread filled with sales pitches and testimonials for a different product which is "better"? Can't we limit that to A vs. B threads? I am thinking of going with 2 P-Mags and would love to see more actual responses about P-Mags.
 
I don't understand why someone asks for data from actual users of a product has his thread filled with sales pitches and testimonials for a different product which is "better"? Can't we limit that to A vs. B threads? I am thinking of going with 2 P-Mags and would love to see more actual responses about P-Mags.

Chris, this forum is about information good and bad. If your mind is made up, then why are you looking at this thread? Are you seeking further justification for your choice?

I've flown behind P-mags for 600+ hours with zero reliability issues. Is that all you want to hear? Should the limitations of a product be avoided just to avoid hurting someones feelings?
 
My experience

My RV7a flew in April 2007 with dual PMAGs and on our flight up to NE last week we turned over 1600 hours on those dual PMAGs. I have had all the updates made during those years and have never been stranded anywhere. I would use them again if I were making the decision again this year.
 
I don't understand why someone asks for data from actual users of a product has his thread filled with sales pitches and testimonials for a different product which is "better"? Can't we limit that to A vs. B threads? I am thinking of going with 2 P-Mags and would love to see more actual responses about P-Mags.


I have to agree with this post.

The anti P-mag posts have gotten to the point where I am reluctant to reply to any P-mag thread.

The OP asked about P-mag reliability and we get multiple posts about how product X is better and verbal attacks on P-mag users.

The P-mags are great ignitions and way ahead of magnetos. Do they extract maximum performance out of an engine, no; however, neither does the ignition in your car or truck.

What they are is easy to install, improve engine performance, and have developed into a reliable ignition.

For that you trade in the ability to custom tune them for every MAP/RPM setting available and fewer parts and connections, which are prone to fail.

Because of the recent attacks on proponents of P-mag ignitions, this long time VAF contributor has simply stopped contributing.
 
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You are a perfect candidate for one of our EIC's. It would have picked up the shaft bearing issues and allowed you to test different configurations.

-4.2 degree shift is what I typically recommend for a "stock" angle valve engine. Did you also reduce your max advance by the same amount?


I like them. I started with traditional mags, switched to one Pmag after 300 hours, then swapped the second out after another 100. Now, with over 1600 hours, I have quite a bit of time evaluating them.

The early issues that were uncovered as the number in the field increased have been addressed with minor modifications and a few program updates. Rather than adding timing features they have chosen to keep the product stable with reliability focused updates. I use the windows EICAD program with a laptop to adjust the parameters but it would be nice to have more options for managing the advance.

One of my old units had started to give an occasional 'magnet out of range error' that prompted my need to get a replacement in hand in a bit of a scramble right before Reno...

Comparing the new one to the old ones... most notably, both of the old units have developed quite a bit of shaft play. I look forward to seeing what the serviced unit looks like when it makes its way back shortly.

I have had an an occasional (perhaps four times) boot up failure that is reportedly addressed with v40+ firmware. Each time it was resolved by shutting down and re-timing.

One coil pack developed a dead post... I received a replacement.

Much later, one coil pack, on two posts, started arcing a bit with the plug wires... this eventually led to an intermittent spark. I suspect that the root issue was a combination of a lack of dielectric paste and a loose attachment. After replacing the plugs, wires, and cleaning the posts it all worked fine. I use dielectric grease now and ensure that the plug end is firmly attaching to the post.

I have spent quite a bit of time with the advance in search of any top end speed... my advance is set at -4.2
 
Before first flight, my mid time engine was modified with for fuel injection and dual pmags. 150+ hrs now troublefree. I like the performance, ease of install and maintenance, less weight, and customer support. I've called the factory twice in two years. On the first call, the owner gave me almost an hour of his time on the phone as I had install questions and he gave copious amounts of background for the design and evolution. I thought this was very nice and unexpected. The second call was the result of a fault code which he suggested sending both in for the V40 upgrade and checkup. This was a no cost to me including return shipping despite being out of warranty as I bought the p-mags from another builder. I love my P-mags.

Bevan.
 
I don't understand why someone asks for data from actual users of a product has his thread filled with sales pitches and testimonials for a different product which is "better"? Can't we limit that to A vs. B threads? I am thinking of going with 2 P-Mags and would love to see more actual responses about P-Mags.

I'm sorry but the above statement is inappropriate . The OP in fact was asking for information by which he could evaluate several systems. He was not asking solely for P-MAG reviews. Therefore a comparison between other systems is entirely appropriate in this thread. I refer to his post:

I’ve priced out 3 options.

2 Slick Mags - $2500
2 P-MAG’s - $3200
G3I Ignition - $4600
 
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I'm sorry but the above statement is inappropriate . The OP in fact was asking for information by which he could evaluate several systems...

Absolutely. Any search of this forum would show that I'm a long time P-mag user and supporter. The company is great and I couldnt be happier with thier customer service. BUT, times change and so does customer expectation. P-mag has been great to me but the fact is there is now a better product out there. After all, Dynon does not soldier on with the D-100 line in the face of Garmins onslaught, right? P-mag was a great ignition once but that stagnation has simply been overtaken by SDS. Not my fault that P-mag is resting on their laurals... Its their choice. If Ross decides to kick back and coast on his existing product then he will eventually be eclipsed... Simple fact of life. If someone is searching for an ignition, I'm going to point them in the "best" direction.

I've burned a lot of avgas testing P-mags and CPI and if the P-mag comes out second, thats not "P-mag bashing" thats just reporting the facts. If someone doesnt like my reporting, they are certainly free to produce contradicting evidence or ignore my posts. No skin off my back, I know the truth.
 
For CPI to fit the OP's bill, you would have to add a redundant power source, and I don't mean a back up battery.
A B&C vacuum pad alternator would 'almost' fit the bill, but it is a single power source, so it's still a little short of the 'self powered' spec for dual ignitions.
CPI single unit ($1170) dual unit ($2275?)
B&C SD-8 with PMR1C-14 and 504-1 (14v) ($545.00)
Total: Single: $1715 dual: $2850
Still in the ball park price-wise, The Dual CPI option is a better price, but if it's a 'one casing device' might lack the redundancy the OP desires.
I run a Pmag and a Bendix mag on my RV-8 and my T-18, a noticeable improvement over 2 mags.
I'm also slowly accumulating parts for a Ford EDIS (possibly with MegaJolt) system. I would probably add the B&C SD8, because I also use dual automotive electric fuel pumps to AFP mechanical fuel injection. I probably have added risk with a single battery system.
An interesting discussion.
 
Ignition choices and P Mag reliability

Mags...... Whe you have run on mags and have the ability to use EI they are chalk and cheese. My original set up was one mag and a Lightspeedaviation. On the mag the engine was very rough compared with the LS. Less power more fuel consumption poorer starting.

When my LS started playing up I initially ran one Pmag and a mag, I was back to where I was before, smooth on th Pmag drop in power when just on the mag, no drop in power or performance when just on the p mag,

I then went to two PMags and set up the most advanced curve. I now had an engine that was smooth on both ignitions if run independently and was happy.

I then added Bills EI commander and on his recommendation moved to the less aggressive curve. There was a noticeable increase in power, EGT and CHT were slightly better, not that they were bad before. Reliability is spot on!

Why did I not go for the crank sensor type of ignition again, well in my view the failure of a single crank sensor could leave you struggling to make it home to the airfield. The failure of a single p mag would still have the engine running smoothly till you got home.

Is the P mag curve totally optimum, probably not but its light years ahead of mags. Do I want to be able to fine tune it myself, well I can because of the EIC but would I want to in flight...like most pilots the answer is no.

To be frank what Michael is doing is well beyond the capability and interest of most pilots, all they want is a good reliably ignition and P Mags are exactly that.
 
Since I did not start this thread, I apologize to Evan for stirring up some people's feathers. I made the assumption that since the title of the thread is "Dual P-MAG Reliability in 2017" that he wanted info specifically about P-Mags since the comparison thread entitled " SDS CDI vs Pmag" would have seen to cover that topic specifically but I stand corrected. As far as being called out by name by one individual questioning my motives, so be it.
 
Mags...... Whe you have run on mags and have the ability to use EI they are chalk and cheese. My original set up was one mag and a Lightspeedaviation. On the mag the engine was very rough compared with the LS. Less power more fuel consumption poorer starting.

When my LS started playing up I initially ran one Pmag and a mag, I was back to where I was before, smooth on th Pmag drop in power when just on the mag, no drop in power or performance when just on the p mag,

I then went to two PMags and set up the most advanced curve. I now had an engine that was smooth on both ignitions if run independently and was happy.

I then added Bills EI commander and on his recommendation moved to the less aggressive curve. There was a noticeable increase in power, EGT and CHT were slightly better, not that they were bad before. Reliability is spot on!

Why did I not go for the crank sensor type of ignition again, well in my view the failure of a single crank sensor could leave you struggling to make it home to the airfield. The failure of a single p mag would still have the engine running smoothly till you got home.

Is the P mag curve totally optimum, probably not but its light years ahead of mags. Do I want to be able to fine tune it myself, well I can because of the EIC but would I want to in flight...like most pilots the answer is no.

To be frank what Michael is doing is well beyond the capability and interest of most pilots, all they want is a good reliably ignition and P Mags are exactly that.

This post captures my desires for an ignition the best. Highest amount of redundancy, and I?m willing to sacrifice extreme top end performance for reliability and redundancy. Still leaning towards dual P-MAG?s. The SDS-CPI, besides the box asthetics, would require a second alternator, which P-MAG?s do not. The P-MAG installation has 5 backups. Alternator, Left PMG, Right PMG, Battery 1 and Battery 2 before the engine stops turning does CPI offer that?
 
Since I did not start this thread, I apologize to Evan for stirring up some people's feathers. I made the assumption that since the title of the thread is "Dual P-MAG Reliability in 2017" that he wanted info specifically about P-Mags since the comparison thread entitled " SDS CDI vs Pmag" would have seen to cover that topic specifically but I stand corrected. As far as being called out by name by one individual questioning my motives, so be it.

I am looking for P-MAG experiences and reliability data as that was the only thing holding me back. I looked at SDS-CPI, Lightspeed, etc...I like multiple layers of redundant systems and I think P-MAG does that. Also it seems like the new shaft retainers, and v40 firmware have turned P-MAG into a very durable system. I think I?m sold.
 
Not redundant enough?

For my own level of comfort, self powered ignitions are not required. Making sure that they receive the necessary electrons to keep running can be handled by good system design and by resource management.

I think the OP already has a backup battery. I don't know how big it is, but it is a form of redundancy. I have 2 PC 680s for my 2 Plasma IIIs. I've done the calcs and can run out my gas without sweat after an alternator failure. I'd have to shut down my second EFIS to be able to run out completely full tanks, but the point is I would have lots of time, hours of it, to find a good place to land and troubleshoot. I considered adding the 8amp alternator and decided that I don't need it and the extra weight for the level of redundancy that I require. I could go with an EarthX to replace one of my 680s and save enough weight for the 2nd alternator, but I still don't think I need it.

I'm not bashing P-mags. I just don't think that they necessarily add redundancy that you can't design for with a different ignition system. If I were choosing today, I'd go with CPI and a wiring design similar to what I have.

Ed Holyoke


For CPI to fit the OP's bill, you would have to add a redundant power source, and I don't mean a back up battery.
A B&C vacuum pad alternator would 'almost' fit the bill, but it is a single power source, so it's still a little short of the 'self powered' spec for dual ignitions.
CPI single unit ($1170) dual unit ($2275?)
B&C SD-8 with PMR1C-14 and 504-1 (14v) ($545.00)
Total: Single: $1715 dual: $2850
Still in the ball park price-wise, The Dual CPI option is a better price, but if it's a 'one casing device' might lack the redundancy the OP desires.
I run a Pmag and a Bendix mag on my RV-8 and my T-18, a noticeable improvement over 2 mags.
I'm also slowly accumulating parts for a Ford EDIS (possibly with MegaJolt) system. I would probably add the B&C SD8, because I also use dual automotive electric fuel pumps to AFP mechanical fuel injection. I probably have added risk with a single battery system.
An interesting discussion.
 
This post captures my desires for an ignition the best. Highest amount of redundancy, and I’m willing to sacrifice extreme top end performance for reliability and redundancy. Still leaning towards dual P-MAG’s. The SDS-CPI, besides the box asthetics, would require a second alternator, which P-MAG’s do not. The P-MAG installation has 5 backups. Alternator, Left PMG, Right PMG, Battery 1 and Battery 2 before the engine stops turning does CPI offer that?

Since it seems some people on this thread are still evaluating choices, I'll respond to this post.

You're still flying a single engined aircraft with several single points of failure. Most commercial airliners don't have even quadruple backups, let alone quintuple redundancy.

On a typical CPI setup you'd have a main battery, single or dual alternators and a backup battery, possibly for other electronics. With the new CPI2, we'll have an option for a additional dedicated backup battery with monitoring system. That's quadruple or quintuple redundant power sources. Enough for a single engined aircraft? Most people would probably think so.

Remember one CPI only draws about 1 amp on a 4 banger at 2400 rpm. An 18 AH backup battery would run one CPI for around 16 hours, 2 CPIs for 8 hours- far more time than you have fuel for. If you want a battery backup, you can do that for about $40 as I've done in my -6A. You don't need a massive battery for backup power with such low current draws.

As Mike said, no inspections outside of annual spark plug checks. P Mag recommends 100 hour inspection intervals requiring removal. I suspect few people actually do these however. CPI requires no blast tubes, there are no moisture concerns and the crank flange mounted sensor system is more reliable than a series of gears and bearings which several people have noted failures on.

The CPI2 will address concerns with appearance, panel space and backup power as well as introduce some new features.

Nothing can beat a P Mag for ease of installation but as always, I invite people considering EIs to look at each potential system available and weigh the pros and cons. No one system is the best for every customer.

Last week, I sent a client who phoned us for a CPI over to P Mag as he had too many things to change to install a CPI in my view. Surprisingly, he'd never even heard of P Mag. In the end, I think he'd be better served with their product given his wants and circumstances.
 
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For my own level of comfort, self powered ignitions are not required. Making sure that they receive the necessary electrons to keep running can be handled by good system design and by resource management.

I think the OP already has a backup battery. I don't know how big it is, but it is a form of redundancy. I have 2 PC 680s for my 2 Plasma IIIs. I've done the calcs and can run out my gas without sweat after an alternator failure. I'd have to shut down my second EFIS to be able to run out completely full tanks, but the point is I would have lots of time, hours of it, to find a good place to land and troubleshoot. I considered adding the 8amp alternator and decided that I don't need it and the extra weight for the level of redundancy that I require. I could go with an EarthX to replace one of my 680s and save enough weight for the 2nd alternator, but I still don't think I need it.

I'm not bashing P-mags. I just don't think that they necessarily add redundancy that you can't design for with a different ignition system. If I were choosing today, I'd go with CPI and a wiring design similar to what I have.

Ed Holyoke

In my opinion, self-powered EI are going to be best method for the masses because they are the closest thing to what they are replacing, the self-contained magneto. For those who want EI and don't want to fiddle with maps, curves, backup batteries, remote boxes and significant wiring changes, and want the engine to keep running if the master switch gets turned off, Pmag is he clear choice.

I don't recall any threads about wanting to adjust timing curves with magnetos.

The Pmag concept is correct. At first there was some concern that the design was not going to be as reliable as a standard mag (all it needs to be in my book) but I think we're at the point now that one can say the Pmags are reliable enough, understood, still installed in redundant pairs as usual, and well supported by the factory. They just work.

Bevan.
 
In my opinion, self-powered EI are going to be best method for the masses because they are the closest thing to what they are replacing, the self-contained magneto. For those who want EI and don't want to fiddle with maps, curves, backup batteries, remote boxes and significant wiring changes, and want the engine to keep running if the master switch gets turned off, Pmag is he clear choice.

I don't recall any threads about wanting to adjust timing curves with magnetos.

The Pmag concept is correct. At first there was some concern that the design was not going to be as reliable as a standard mag (all it needs to be in my book) but I think we're at the point now that one can say the Pmags are reliable enough, understood, still installed in redundant pairs as usual, and well supported by the factory. They just work.

Bevan.


The above is fine given the context that the idea to emulate a magneto is a "marketing decision". Unitized construction is a means to differentiate their product, and no doubt it has appeal with some. But the decision to go down that path was certainly challenging, as the reliability reports from the past will clearly attest. But unitized construction is far from the "correct" choice from an engineering standpoint, as evidenced by the near complete abandonment of that concept decades ago by virtually every other vehicle manufacturer. Billions of miles of operation show that the distributed system like CPI also "...just work..." to paraphrase the above. Plenty of ways to skin a cat.

Now, the OP's requirement has become clear that he wants a very, very high level of redundancy and complete isolation from ships power. Thats his right and clearly if he sticks with that requirement, all battery ignitions are off the table. Pretty much limits the options available. And if the discussion turns to probability of failure of ships power, that is a WHOLE different can of worms.

Sounds like the OP is pointed in the direction that makes him comfortable. Thats a good thing. Its also a good thing that we can share information in a civilized manner, even if the information is not what we want to hear. We need to remember this is largely a data driven excercise, not politics or religion.
 
The Pmag concept is correct. At first there was some concern that the design was not going to be as reliable as a standard mag (all it needs to be in my book) but I think we're at the point now that one can say the Pmags are reliable enough, understood, still installed in redundant pairs as usual, and well supported by the factory. They just work.

Bevan.

The misconception about PMAGs is that if you have two of them you automatically have redundancy. But that has not always proven to be the case. Their specific weakness is that they have been susceptible to losing their timing. And if one of the PMAGs loses its timing to a very advanced position it can cause the engine to quit, regardless of the type of ignition system on the other side. In other words one faulty PMAG can take out a second PMAG, or it can take out a Lightspeed EI, or it can take out a conventional magneto.

This type of failure, whereby the failure of one ignition renders the second ignition useless, is a characteristic of PMAGs. I have never heard of a single case, ever, of such a thing happening with dual magnetos.

It may well be that bolting all of the solid state components for the PMAG system directly to the engine in such a hot, vibrating environment will always be problematic. I'm not sure about that.

A number of aircraft with dual PMAGs have had complete engine failures after the timing was lost on just one PMAG. There are other incidences of serious engine damage being caused by the same problem. At this very moment there is another thread on VansAirforce dealing with exactly that scenario whereby the owner had to have his whole top end overhauled because he lost timing on his single PMAG which rendered his second conventional magneto useless. See here:

http://www.vansairforce.com/community/showthread.php?t=144336

It seems to me that the PMAG is always one revision, one recall, one software update from being the genuine article.

My personal opinion is that ALL of the EI systems for Lycomings have their own serious limitations. I have a conventional magneto on one side and a Lightspeed EI on the other. The limitations of the Lightspeed system is that it is dependent on external electrons and it has a lot of exposed wiring and connectors that can fail or be damaged. But it seems to be relatively immune to loss of timing. Would I use two Lightspeed ignitions....no way Jose....too much downside and virtually no additional gain.

I find that having EI on one side greatly improves engine performance and I am prepared to put up with the increased risks of the system for that advantage. But I am not kidding myself that my system is as safe and reliable as two conventional magnetos. And neither should you.
 
Since it seems some people on this thread are still evaluating choices, I'll respond to this post.

You're still flying a single engined aircraft with several single points of failure. Most commercial airliners don't have even quadruple backups, let alone quintuple redundancy.

On a typical CPI setup you'd have a main battery, single or dual alternators and a backup battery, possibly for other electronics. With the new CPI2, we'll have an option for a additional dedicated backup battery with monitoring system. That's quadruple or quintuple redundant power sources. Enough for a single engined aircraft? Most people would probably think so.

Remember one CPI only draws about 1 amp on a 4 banger at 2400 rpm. An 18 AH backup battery would run one CPI for around 16 hours, 2 CPIs for 8 hours- far more time than you have fuel for. If you want a battery backup, you can do that for about $40 as I've done in my -6A. You don't need a massive battery for backup power with such low current draws.

As Mike said, no inspections outside of annual spark plug checks. P Mag recommends 100 hour inspection intervals requiring removal. I suspect few people actually do these however. CPI requires no blast tubes, there are no moisture concerns and the crank flange mounted sensor system is more reliable than a series of gears and bearings which several people have noted failures on.

The CPI2 will address concerns with appearance, panel space and backup power as well as introduce some new features.

Nothing can beat a P Mag for ease of installation but as always, I invite people considering EIs to look at each potential system available and weigh the pros and cons. No one system is the best for every customer.

Last week, I sent a client who phoned us for a CPI over to P Mag as he had too many things to change to install a CPI in my view. Surprisingly, he'd never even heard of P Mag. In the end, I think he'd be better served with their product given his wants and circumstances.

Is this really the only advantage of CPI over PMAG, 100 hour inspection vs. no inspection? BTW, my understanding has been that PMAG asks to inspect at each annual which is relatively a minor inspection.

With CPI, do we ever need to inspect the crank sensor position/mount or is that not required at all?
 
The misconception about PMAGs is that if you have two of them you automatically have redundancy. But that has not always proven to be the case. Their specific weakness is that they have been susceptible to losing their timing. And if one of the PMAGs loses its timing to a very advanced position it can cause the engine to quit, regardless of the type of ignition system on the other side. In other words one faulty PMAG can take out a second PMAG, or it can take out a Lightspeed EI, or it can take out a conventional magneto.

This type of failure, whereby the failure of one ignition renders the second ignition useless, is a characteristic of PMAGs. I have never heard of a single case, ever, of such a thing happening with dual magnetos.

This comment carries some weight with me, however I believe in fairness to the folks at EMagAir the comment should be qualified. I watch ignition discussions reasonably closely on this forum and don't believe I've seen any significant complaints of a PMag losing it's timing if running Version 40 firmware.

If one has their PMag updated to V40 it would appear the loss of timing events may well be a thing of the past. As a V40 user I certainly hope that's the case.
 
Problem solved!

This comment carries some weight with me, however I believe in fairness to the folks at EMagAir the comment should be qualified. I watch ignition discussions reasonably closely on this forum and don't believe I've seen any significant complaints of a PMag losing it's timing if running Version 40 firmware.

If one has their PMag updated to V40 it would appear the loss of timing events may well be a thing of the past. As a V40 user I certainly hope that's the case.

This is the problem with this kind of thread. The OP was asking about V40 P mags against mags and one other ignition system. V40 solved the loss of timing issue but someone brings it into the debate, why?
 
V40 solved the loss of timing issue but someone brings it into the debate, why?

I refer again to the concurrent thread 'PMAG Problem' on VansAirforce. The OP of that thread, Loal Wood, required a top end job done on his Lycoming after his sole PMAG lost timing. This is what Loal Wood had to say on his thread following a discussion with Brad at Emag about the incident:

I talked to Brad at Emagair about the evaluation of my Pmag. This is what I learned.

The inspection of my Pmag did not reveal any damage or discrepancies.

My Pmag did not have the V40 update installed.

As stated on the Emag website V40 is not a mandatory update.

He said there is no reason to believe that the V40 update would have prevented my loss of timing issue anymore than the V37 that was installed at the time of the event.

Brad said they do not have enough definitive information at this point to know why this inflight timing event happened.


Now, if I'm reading this right EMAG have stated that they do not know why Loal's PMAG (V37) lost its timing and they have no reason to believe that V40 would have prevented the timing loss.
 
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I refer again to the concurrent thread 'PMAG Problem' on VansAirforce. The OP of that thread, Loal Wood, required a top end job done on his Lycoming after his sole PMAG lost timing. This is what Loal Wood had to say on his thread following a discussion with Brad at Emag about the incident:

I talked to Brad at Emagair about the evaluation of my Pmag. This is what I learned.

The inspection of my Pmag did not reveal any damage or discrepancies.

My Pmag did not have the V40 update installed.

As stated on the Emag website V40 is not a mandatory update.

He said there is no reason to believe that the V40 update would have prevented my loss of timing issue anymore than the V37 that was installed at the time of the event.

Brad said they do not have enough definitive information at this point to know why this inflight timing event happened.


Now, if I'm reading this right EMAG have stated that they do not know why Loal's PMAG (V37) lost its timing but they doubt that V40 would have prevented the timing loss.

In my opinion, there were/are too many unanswered questions in this case to draw a conclusion as to what really happened there.
 
Loss of timing

If we are talking about the incident where arcing at the alternator apparently caused this failure, my recollection was that V40 was designed to prevent this type of issue.


However that is why we have dual ignition systems, if one malfunctions you go to the other and land ASAP. When my LSE ignition started to play up I knew straight away and wen to the mag. No damage to the engine at all.

Actually I may well fit a a different type of ignition in my next lycoming, with fuel injection, but am a happy PMag customer especially with Bills EIC as you can monitor the mags and see what is going on with them.
 
Is this really the only advantage of CPI over PMAG, 100 hour inspection vs. no inspection? BTW, my understanding has been that PMAG asks to inspect at each annual which is relatively a minor inspection.

With CPI, do we ever need to inspect the crank sensor position/mount or is that not required at all?

You directed this at Ross, but I?ll be happy to add my thoughts as well (What a shock, right?).

P-mag wants you to remove the units and do an inspection. The act of removal and replacement is not horrible, but opening up the back of the engine every hundred hours is not fun and definitely increases the risk of dropping hardware into that gaping hole. But the inspection itself is compelling. You are looking to see that all that stuff is still in place. Shaft endplay, magnet alignment? All that stuff is important and let?s face it, fragile. Plenty of warnings to handle this with kid gloves in the P-mag manual. In contrast, the CPI sensor is bolted to the side of the case with a mount stout enough to lift the engine with. If you have an end play or magnet misalignment problem, the crankshaft is broken.

So yes, to answer your question ? zero maintenance for CPI.

Further, the CPI sensor is potted so it is essentially chemical proof. If you want to wash the engine down with solvent or degreaser, you?re not going to hurt the sensor. Contrast this with P-mag, where the case is open vented. You have to cover the Pmags with plastic or remove them to wash down the engine because the boards will get soaked. And yes, it happens. I had a board replaced because solvent entered the case and ate the board.

But the maintenance free aspect is not the primary advantage of CPI. That belongs to the fact that the P-mag curve ? even the most conservative one ? is too aggressive. We have known for years that P-mag equipped engines run warmer and some even exhibit ?CHT issues?. And thanks to the fairly recent flight test efforts an dissection of their curve by several members here, the cause is now clear: Too much advance at high power. In fact, the issue is so well known that even the maker of the third party programmer recommends his product should be used to adjust the problem away. That, or you can mechanically retard the timing (as I?ve done on my -8). But this doesn?t really solve the fundamental issue, it just masks it. True, people are not melting down engines and the issue is manageable by ?spoofing? the standard program, but why not get an ignition that works right out of the box?

And on the subject of ignition curves, P-mag doesn?t even offer the LOP switch function of CPI. This is a very useful feature and a compelling discriminator for those that do cross country work.

So CPI delivers a safe, cool advance curve for takeoff and climb, as well as a fuel stretching LOP setting and everything in between. The components are robust, proven with decades of use, and maintenance free.
 
You directed this at Ross, but I’ll be happy to add my thoughts as well (What a shock, right?).

P-mag wants you to remove the units and do an inspection. The act of removal and replacement is not horrible, but opening up the back of the engine every hundred hours is not fun and definitely increases the risk of dropping hardware into that gaping hole. But the inspection itself is compelling. You are looking to see that all that stuff is still in place. Shaft endplay, magnet alignment… All that stuff is important and let’s face it, fragile. Plenty of warnings to handle this with kid gloves in the P-mag manual. In contrast, the CPI sensor is bolted to the side of the case with a mount stout enough to lift the engine with. If you have an end play or magnet misalignment problem, the crankshaft is broken.

So yes, to answer your question – zero maintenance for CPI.

Further, the CPI sensor is potted so it is essentially chemical proof. If you want to wash the engine down with solvent or degreaser, you’re not going to hurt the sensor. Contrast this with P-mag, where the case is open vented. You have to cover the Pmags with plastic or remove them to wash down the engine because the boards will get soaked. And yes, it happens. I had a board replaced because solvent entered the case and ate the board.

But the maintenance free aspect is not the primary advantage of CPI. That belongs to the fact that the P-mag curve – even the most conservative one – is too aggressive. We have known for years that P-mag equipped engines run warmer and some even exhibit “CHT issues”. And thanks to the fairly recent flight test efforts an dissection of their curve by several members here, the cause is now clear: Too much advance at high power. In fact, the issue is so well known that even the maker of the third party programmer recommends his product should be used to adjust the problem away. That, or you can mechanically retard the timing (as I’ve done on my -8). But this doesn’t really solve the fundamental issue, it just masks it. True, people are not melting down engines and the issue is manageable by “spoofing” the standard program, but why not get an ignition that works right out of the box?

And on the subject of ignition curves, P-mag doesn’t even offer the LOP switch function of CPI. This is a very useful feature and a compelling discriminator for those that do cross country work.

So CPI delivers a safe, cool advance curve for takeoff and climb, as well as a fuel stretching LOP setting and everything in between. The components are robust, proven with decades of use, and maintenance free.

Thanks Michael for summing up the advantages here, things that had become the needle in the stack in the other thread.

Considering that I am somewhat familiar with the maintenance recommendation of PMAG “ the opening up the back of the engine and all that you listed” I will leave that portion out of the discussion since the complexity and risk of it seems to be a matter of opinion.

What I like to know, what advance curve is provided by CPI and how much of customization is expected for the end users/customer? Not all of us are either interested or knowledgeable in finding the best curve thru hours and hours of flight testing. With CPI, right out of the box, do I get a default timing that is an improvement over other EIS and what is involved in the switch for LOP (both in terms of installation and usage) Is it just a toggle switch?

I appreciate the info.
 
What I like to know, what advance curve is provided by CPI and how much of customization is expected for the end users/customer? Not all of us are either interested or knowledgeable in finding the best curve thru hours and hours of flight testing. With CPI, right out of the box, do I get a default timing that is an improvement over other EIS and what is involved in the switch for LOP (both in terms of installation and usage) Is it just a toggle switch?

I appreciate the info.

I see many comments on EI threads basically saying that lots of people don't care to know if the ignition curves are optimized for their engines, as long as the thing keeps sparking. This has been the case with all the older EIs without a standard, user friendly pilot interface.

So with CPI, every sale is for an individual engine and client, not a one solution fits all. We ask engine type, CR fuel octane and will enter a custom base map for you if desired, slightly conservative to be safe. No need for you to do any programming if you don't want to.

To think that an A or B curve suits every engine and mission out there is simply nonsense. No way it's optimal for all engines, where we commonly have CRs from 7.5 to 10 and even higher in some cases. Data plate timing for IO-390s is a lot less than most other Lycomings, many people run mostly on mogas, some fly low or high, some fly ROP, some LOP. Interesting how many seem to discount the science of flight testing results by Nigel, Dan and Michael here on VAF.

In short, we can enter a safe curve for YOUR engine and mission, no need for you to do much if you don't want to. Likewise you have the ability to fine tune (in logical 1 degree increments) if you wish, plus change the amount of LOP advance which is selected on/off with a small toggle switch.

So, there is no "standard" advance curve with our products unless you don't give us any details, in which case, we'll generally enter 24 degrees of rpm timing for O-235, 290, 320, 360, 540 engines and 20 degrees on IO-390 engines with zero MAP advance or retard- pretty much standard mag timing. But, this would not be a good idea on a 10 to 1 engine running mogas.
 
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I see many comments on EI threads basically saying that lots of people don't care to know if the ignition curves are optimized for their engines, as long as the thing keeps sparking. This has been the case with all the older EIs without a standard, user friendly pilot interface.

So with CPI, every sale is for an individual engine and client, not a one solution fits all. We ask engine type, CR fuel octane and will enter a custom base map for you if desired, slightly conservative to be safe. No need for you to do any programming if you don't want to.

To think that an A or B curve suits every engine and mission out there is simply nonsense. No way it's optimal for all engines, where we commonly have CRs from 7.5 to 10 and even higher in some cases. Data plate timing for IO-390s is a lot less than most other Lycomings, many people run mostly on mogas, some fly low or high, some fly ROP, some LOP. Interesting how many seem to discount the science of flight testing results by Nigel, Dan and Michael here on VAF.

In short, we can enter a safe curve for YOUR engine and mission, no need for you to do much if you don't want to. Likewise you have the ability to fine tune (in logical 1 degree increments) if you wish, plus change the amount of LOP advance which is selected on/off with a small toggle switch.

So, there is no "standard" advance curve with our products unless you don't give us any details, in which case, we'll generally enter 24 degrees of rpm timing for O-235, 290, 320, 360, 540 engines and 20 degrees on IO-390 engines with zero MAP advance or retard- pretty much standard mag timing.

Thank you Ross for the info, I appreciate having the option and flexibility to fine tune the curve if I can but also I, unlike some, have little knowledge of fine tuning the curve.
Is there some data that compares a fined tuned curve of your system vs. the stock curve, lets say curve A of a PMAG in terms of fuel saving/additional power, etc? I am hoping to see a measureable difference (perhaps fuel burn would be a good measureable indicator).
 
... and what is involved in the switch for LOP (both in terms of installation and usage) Is it just a toggle switch?..

Last question first:

The LOP function is activated by applying system voltage to a discrete pin in the CPI connector. The physical interface for the LOP function is a toggle switch in my case. The LOP function is programmed by scrolling through the CPI windows until you get to a discrete LOP window. You simply toggle up or down to get the additional advance you want (3 degrees in my case). Once set, activation of the LOP switch simply tacks on an additional 3 degrees advance to the existing map. If you’re idling at 20 degrees, then activating the switch will give you 23 (20 + 3). If you’re at the top of climb and the normal RPM and MAP values have you at, say, 32 degrees, then the LOP switch give you 35 (32+3). It’s also noteworthy that this function is deactivated at high MP levels. So if you forget to turn off the switch and do a go around, no problem.

I'm glad Ross answered the “as delivered” program because I never used it. I went straight to building my own. A casual glance in the manual shows it to be very conservative at high power though, and testing confirms that’s exactly what is needed. In fact, my testing shows that even Lycoming’s data plate timing value is more than required for takeoff. My program pulls up to 5 degrees off the data plate value in some circumstances. And for the record, I'm stock (8.5) compression.
 
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Thank you Ross for the info, I appreciate having the option and flexibility to fine tune the curve if I can but also I, unlike some, have little knowledge of fine tuning the curve.
Is there some data that compares a fined tuned curve of your system vs. the stock curve, lets say curve A of a PMAG in terms of fuel saving/additional power, etc? I am hoping to see a measureable difference (perhaps fuel burn would be a good measureable indicator).

I've only had quick glances some time ago at what Pmag runs for timing, it doesn't really concern us. I'd look at what Nigel, Dan and Michael have posted here and at Nigel's Kitplanes article if you want to see what works best on THEIR engines. This will give you some idea of where Pmag maybe has too much or too little advance in their curves.

Too much or too little may cause power loss or CHT issues and too much can reduce detonation margins, especially on mogas with high CHTs and IATs. Too little is generally safer than too much. I think Nigel's data is the most complete and Michael's showed us the extremes of WOT/SL vs. LOP/ low MAP up high.

I think the OP was really asking if the original software, hardware problems experienced by Pmags were now licked and only interested in actual reliability in delivering sparks in the Pmag offerings of today. You'll get different answers from different people depending on their experiences. This thread has taken a new direction discussing other factors outside reliability. I'm not sure that serves the purpose of the OP's question. There have already been other threads comparing the various EIs available today.
 
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...Is there some data that compares a fined tuned curve of your system vs. the stock curve, lets say curve A of a PMAG in terms of fuel saving/additional power, etc? I am hoping to see a measureable difference (perhaps fuel burn would be a good measureable indicator).

No side by side comparison but I have enough practical experience with both to throw out an informed opinion.

This issue is the breadth of the curve. P-mags deliver very good LOP efficiency because they advance far enough to do some good up in that rarified air. Unfortunately, they start advancing so early that down low and rich they make plenty of heat and cylinder pressure, but don't do more work. Plenty of credible flight test results on this site to review for confirmation.

In short, a good hot spark can be delivered by any EI, and the engine architecture does the rest when LOP. Rich mixtures are easy to light and there's really no difference what lights it off. But timing is everything.

The compelling issue is if the EI can advance far enough to light the LOP mixture, pull it back enough for the best power mixture, and retard enough to protect the engine at the SL, 100% power mixture. Most any EI can deliver on some of these conditions, but CPI does all of them and that's where the "performance advantage" is found.

And I do agree that the OP's question has been answered long ago. Maybe the mods can split the "comparison" posts out into a more appropriate thread. My apologies for my role in the OT.
 
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