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Mags: IRAN Or Exchange?


AlexLev

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Looking to service my mags. Do you send them for a 500-hour IRAN?

OR

Swap them out for an overhauled exchange? Curious if anyone has recommendations for the overhaul exchange option as far as who they use?

Edited by AlexLev
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Looking to service my mags. Do you send them for a 500-hour IRAN?
OR
Swap them out for an overhauled exchange? Curious if anyone has recommendations for the overhaul exchange option as far as who they use?
I'm looking at the same decision tree...I dug into my logbooks and I discovered that the mags where overhauled at 1392 hrs total airframe time then IRAN'ed twice since then. Based on that, I'm going with new ones and while I'm at it, I'm probably going to install a SureFly "eMag" and new wiring harnesses

Sent from my Pixel 3 XL using Tapatalk

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I'm interested in this topic.  Next week my left mag is getting replaced with a surefly and my right mag will need overhaul or IRAN or swap.  My A&P is going to send my right to texas had have it overhauled I think.  I'd love to hear about what others have done.  

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My mags get IRAN'd once at 500 hours then they are gone at 1000 hours replaced with brand new. I just consider cost of maintenance. By doing this, I stopped all mag problems. O/H exchange is a crap shoot, usually craps. There is some belief out there you can O/H or IRAN these things forever which is not true. When Continental bought Bendix mags, they were appalled at the condition of the core inventory and that is why they junked them all and replaced the cores with new. 5 years ago if you bought an O/H exchange Bendix mag, it was a highly likely it was a brand new unit. There needs to be a revision on how we view magnetos. They are not capable of more than a few O/H or IRANS, then they are done. I will bet if you start doing some work with a precision optical comparator one would be truly amazed at what we reinstall back into our airplanes for ignition units.

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Don't know if it's an urban legend around the mechanic's world, but word has it that you can overhaul a Bendix magneto for ever while Slicks aren't good candidates for overhaul.

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29 minutes ago, drapo said:

Don't know if it's an urban legend around the mechanic's world, but word has it that you can overhaul a Bendix magneto for ever while Slicks aren't good candidates for overhaul.

That is true, but even then I don't keep a Bendix mag more than 1000 hours.

 

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Longevity and reliability of magnetos have a lot to do with who does the work.  This is what gets replaced by Aircraft Magneto Service in Montana, and what they look like when they’re finished with them.

Clarence

DA200B16-816B-456C-8023-095DB3D140B8.jpeg

B8D7BD42-A5A5-4DB6-BCC4-6248EDB76028.jpeg

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2 hours ago, drapo said:

Don't know if it's an urban legend around the mechanic's world, but word has it that you can overhaul a Bendix magneto for ever while Slicks aren't good candidates for overhaul.

Slick don’t make good candidates due to the cost, a few years back there were some really junk PMA’ed parts that didn’t help Slicks reputation (high failure rates). I just replaced a Slick with over 2000 hrs, it had never been in for ANY type of service, the only thing in the logs was Points & Capacitor at 1200 hrs of service 

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23 minutes ago, M20Doc said:

Longevity and reliability of magnetos have a lot to do with who does the work.  This is what gets replaced by Aircraft Magneto Service in Montana, and what they look like when they’re finished with them.

Clarence

DA200B16-816B-456C-8023-095DB3D140B8.jpeg

B8D7BD42-A5A5-4DB6-BCC4-6248EDB76028.jpeg

they replace the impulse coupler spring and fly weights every 500hr?

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Think about it. How long until the cast housing stretches? You can put all the new "guts" in, but when you are finished, you still have a cast housing that is taking a beating, from the bearing races to the seal seats, to the threads the screws turn into, not to mention the flanges which are bolted down with steel billets. Also for whatever reason, many places check the coils but do not replace the coils. Seen a lot of recently O/H mags come up with a bad coil, because they test good on the bench until you heat stress them then it all goes bad. After 1000 hours, I want a new coils and a new coils are about 400 bucks. Add in the rest of the parts and labor and you might as well buy new. Plus when it goes bad, there is no head scratching and "I'll send it back for a rework", you get a new magneto. IMHO, in a SE airplane, the gods of high tension electricity must all  be simultaneously appeased for their wrath of each is mighty. 

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7 hours ago, alextstone said:

I'm looking at the same decision tree...I dug into my logbooks and I discovered that the mags where overhauled at 1392 hrs total airframe time then IRAN'ed twice since then. Based on that, I'm going with new ones and while I'm at it, I'm probably going to install a SureFly "eMag" and new wiring harnesses

Sent from my Pixel 3 XL using Tapatalk
 

This is my plan... Although since my mags are probably a year or two away from needing it, I am hoping that they will begin to allow both mags to be replaced with the E mags.

 

I really don't understand the logic in keeping 1 old school... I get the reason, that being "tried and true" but the thing is, they are NOT that tried and true.  They are a very important device with a mechanical means of failure and a high wear rate.  The whole POINT of having 2 is in case 1 fails.  Is the FAA that scared that an E-mag might fail that they think 2 of them may fail at the SAME TIME?

Crazy

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E-mags in the field are still soooo new.

Their actual means of failure haven’t been detailed very well yet...

MS has quite a few around the US... we are collecting experience by the day....

It will be interesting to see how well they do with the Heats from very hot to verrrrry cold....

They have the opportunity to really blow away the ancient competition...

They also have the opportunity to be very disappointing too....

A failed mag won’t matter if it was electric or standard after it is dead...

PP thoughts only, not a mechanic...

Best regards,

-a-

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37 minutes ago, Austintatious said:

This is my plan... Although since my mags are probably a year or two away from needing it, I am hoping that they will begin to allow both mags to be replaced with the E mags.

 

I really don't understand the logic in keeping 1 old school... I get the reason, that being "tried and true" but the thing is, they are NOT that tried and true.  They are a very important device with a mechanical means of failure and a high wear rate.  The whole POINT of having 2 is in case 1 fails.  Is the FAA that scared that an E-mag might fail that they think 2 of them may fail at the SAME TIME?

Crazy

Neither of the current approved electronic mags supplies its own power or has a backup power source.  Too many things can go wrong in your electrical system to count on it.  If the emags ever get certified with their own power, then maybe but they’ve been trying for a long time.  They sound like BK at this point.

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2 hours ago, Austintatious said:

This is my plan... Although since my mags are probably a year or two away from needing it, I am hoping that they will begin to allow both mags to be replaced with the E mags.

 

I really don't understand the logic in keeping 1 old school... I get the reason, that being "tried and true" but the thing is, they are NOT that tried and true.  They are a very important device with a mechanical means of failure and a high wear rate.  The whole POINT of having 2 is in case 1 fails.  Is the FAA that scared that an E-mag might fail that they think 2 of them may fail at the SAME TIME?

Crazy

As a career EE I'm not so sure it is as 'crazy' as you think.  Beyond the dependence upon EXTERNAL electrical power, I have seen enough ESD caused electronic component failures to be VERY nervous with both mags being electronic.  Nearby lightning strike comes to mind.  Further, beyond easy starts (and, one E-mag will do that) I'm not convinced they provide much, if any, benefit for a stationary engine such as those in our aircraft.

I'm happy to keep my tractor mags:D

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10 hours ago, GeeBee said:

Think about it. How long until the cast housing stretches? You can put all the new "guts" in, but when you are finished, you still have a cast housing that is taking a beating, from the bearing races to the seal seats, to the threads the screws turn into, not to mention the flanges which are bolted down with steel billets. Also for whatever reason, many places check the coils but do not replace the coils. Seen a lot of recently O/H mags come up with a bad coil, because they test good on the bench until you heat stress them then it all goes bad. After 1000 hours, I want a new coils and a new coils are about 400 bucks. Add in the rest of the parts and labor and you might as well buy new. Plus when it goes bad, there is no head scratching and "I'll send it back for a rework", you get a new magneto. IMHO, in a SE airplane, the gods of high tension electricity must all  be simultaneously appeased for their wrath of each is mighty. 

I’d be far more concerned with the stresses that the rest of the engine is enduring than the magneto case which is only supporting spinning parts not reciprocating parts.

From these pages, my guess is that more mags fail to say attached to the engine because of poor installation, than mags that fail internally.

Clarence

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6 hours ago, toto said:

Interesting, thanks for that. I didn't realize that it was possible to buy new Bendix dual mags today.

That would be interesting if they do.  There  are still lots of D3000 magnetos in lots of airframes.

Clarence

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