Mag inspection on J models?

[nels]

I've noticed some J models advertised with a note that the 500 hr inspection has been done on the mags. From what I can tell, unlike earlier models, all J's have a single shaft that runs two mags, is this the case? I assume there must be or has been an AD on the mags? If so was there ever a permanent fix?

[Guest]

The IO360A3B6D engine had the Bendix D3000 dual drive magneto.  The IO360A3B6 engine has been "upgraded" to two independent Unison/Slick/Champion magnetos, thereby doubling your chances of failure.  A properly maintained D3000 is as reliable as a modern Champion magneto.

Clarence

[rgpilot]

We had a total mag failure in a 1980 J caused by a grounding problem. I believe there was a service bulletin or AD that addressed the need for an additional ground so that both halves of the mag were grounded. Serviced the mag every 500 hrs and never had any further problems. 

[nels]

10 hours ago, M20Doc said:

The IO360A3B6D engine had the Bendix D3000 dual drive magneto.  The IO360A3B6 engine has been "upgraded" to two independent Unison/Slick/Champion magnetos, thereby doubling your chances of failure.  A properly maintained D3000 is as reliable as a modern Champion magneto.

Clarence

Does the Bendix unit require a 500 hr inspection and the upgraded Champion unit has no particular inspection time table? What is the failure mode with the Bendix unit?

also, not sure what you mean by "doubling your chances of failure".

[1524J]

I'm guessing Clarence meant doubling the chances of not failing since the mags would be independent of one another.

[Guest]

13 minutes ago, nels said:

Does the Bendix unit require a 500 hr inspection and the upgraded Champion unit has no particular inspection time table? What is the failure mode with the Bendix unit?

also, not sure what you mean by "doubling your chances of failure".

Both magnetos are subject to recurring 500 hour checks.  A well maintained Bendix is at least as reliable as the current crop of Champion magnetos.  Doubling your chances of failure tongue and cheek for poor quality from Champion.  

Clarence

[nels]

1 minute ago, 1524J said:

I'm guessing Clarence meant doubling the chances of not failing since the mags would be independent of one another.

Ok, that makes more sense.

Can I assume while looking for a J model that the Champion upgrade is desirable but not a deal killer?

[1524J]

It wouldn't kill the deal for me since I bought a Mooney with the dual mag.....I'm fairly confident others might disagree.

[N201MKTurbo]

The dual mag is really two mags in one case. the only thing common between them is the center shaft with a drive gear and the point cam. The major failure that takes them both out is if the whole mag falls off the engine. Which is not unheard of.

[jetdriven]

13 hours ago, M20Doc said:

The IO360A3B6D engine had the Bendix D3000 dual drive magneto.  The IO360A3B6 engine has been "upgraded" to two independent Unison/Slick/Champion magnetos, thereby doubling your chances of failure.  A properly maintained D3000 is as reliable as a modern Champion magneto.

Clarence

Better still is two independent Bendix 1200 series mags, in place of those Slicks.  

[PTK]

Unfortunately Lycoming doesn't give us the choice to select mags. They ship Slicks.

[nels]

This site sure has a lot of information available in its member network!

[jetdriven]

55 minutes ago, PTK said:

Unfortunately Lycoming doesn't give us the choice to select mags. They ship Slicks.

The two Bendix mags with harness were around 1500$, but I got 1000$ for the two slicks off VAF, so I paid 500$ plus labor for a much more reliable setup.  

[Guest]

1 hour ago, jetdriven said:

Better still is two independent Bendix 1200 series mags, in place of those Slicks.  

I have a pair of those with 8 wires each.  Some Piper 180 Arrows had 1200 series mags as well.

Clarence

[jetdriven]

Yes, but no Mooneys from the factory or from Lycoming come with those. . Sometimes you gotta build your own '78 camaro with a 4-barrel and a 350.  After the first failure at 7 hours (kelly overhauls) its been great for the last 400 hours.

Next up, carbon fiber lower gear doors. I love LASAR but their chopped-strand mat and polyester resin plastic gear doors don't belong on a child's pedal car, much less a 200 MPH airplane where they pull open at speed.

 

Edited April 13, 2016 by jetdriven

[bradp]

I have the A3B6 and dealt with slick mag fiasco.  Ask any remotely busy mechanic what their experience has been like with the quality of champion / slick mags and they will mostly agree they are like 9v smoke detector batteries super glued to a toy merry go round in terms of quality.  I spent many months troubleshooting poor starting problems that were traced to an overhaul with "new" slick parts.  I still have the slicks but have cursed them a number of times and have changed to fine wire plugs, which somewhat helps the problem.  My L mag wouldn't start until I sent it back to the overhaul shop and said I'm done with this POS.   They sent me a circa 1996 mag that had been sitting on their shelf and it works.  

Based on byrons experience I've considered swapping to 1200's   They have a strong spark.  A very strong spark.  

Although slicks are not optimal they are passable.  Don't send to Kelly and be careful about how they are bench tested.  Heating seems to be their enemy.... I.e. Mag gets hot in the back of the accessory case and the spark gets weak.  Poor quality secondary coils expand and breaks in the fine wire wrap have been hypothesized as a cause.  A good shop will bench test slick mags after baking in the over to appx 200F. 

[d0tnet]

The dual mag is really two mags in one case. the only thing common between them is the center shaft with a drive gear and the point cam. The major failure that takes them both out is if the whole mag falls off the engine. Which is not unheard of.

Ive been the told this was due to improper tightening of the mag clamps and should be a non issue if properly torqued etc since there is a nylon lock nut being used. Even still, I constantly check the security of the clamps.

Has anyone used replacement hardware with crush washers and/or safety wired the nuts?

[PTK]

1 hour ago, d0tnet said:

Ive been the told this was due to improper tightening of the mag clamps and should be a non issue if properly torqued etc since there is a nylon lock nut being used. Even still, I constantly check the security of the clamps.

Has anyone used replacement hardware with crush washers and/or safety wired the nuts?

http://www.lycoming.com/Portals/0/techpublications/serviceinstructions/SI%201508C%20(02-10-2011)/Dual%20Magneto%20Attachment.pdf

[d0tnet]

1 hour ago, d0tnet said: Ive been the told this was due to improper tightening of the mag clamps and should be a non issue if properly torqued etc since there is a nylon lock nut being used. Even still, I constantly check the security of the clamps.

Has anyone used replacement hardware with crush washers and/or safety wired the nuts?

http://www.lycoming.com/Portals/0/techpublications/serviceinstructions/SI%201508C%20(02-10-2011)/Dual%20Magneto%20Attachment.pdf

Thanks for sharing!

Sent from my XT1254 using Tapatalk

[jetdriven]

2 hours ago, d0tnet said:

Ive been the told this was due to improper tightening of the mag clamps and should be a non issue if properly torqued etc since there is a nylon lock nut being used. Even still, I constantly check the security of the clamps.

Has anyone used replacement hardware with crush washers and/or safety wired the nuts?

Nylock nuts are not the proper hardware.  Neither are crush washers. 

Follow the Lycoming service bulletin to the letter and it will be fine.

[jetdriven]

8 hours ago, bradp said:

I have the A3B6 and dealt with slick mag fiasco.  Ask any remotely busy mechanic what their experience has been like with the quality of champion / slick mags and they will mostly agree they are like 9v smoke detector batteries super glued to a toy merry go round in terms of quality.  I spent many months troubleshooting poor starting problems that were traced to an overhaul with "new" slick parts.  I still have the slicks but have cursed them a number of times and have changed to fine wire plugs, which somewhat helps the problem.  My L mag wouldn't start until I sent it back to the overhaul shop and said I'm done with this POS.   They sent me a circa 1996 mag that had been sitting on their shelf and it works.  

Based on byrons experience I've considered swapping to 1200's   They have a strong spark.  A very strong spark.  

Although slicks are not optimal they are passable.  Don't send to Kelly and be careful about how they are bench tested.  Heating seems to be their enemy.... I.e. Mag gets hot in the back of the accessory case and the spark gets weak.  Poor quality secondary coils expand and breaks in the fine wire wrap have been hypothesized as a cause.  A good shop will bench test slick mags after baking in the over to appx 200F. 

The coils break down and quit working. The rotor melts and the metal part of it falls off. The breaker point cam, made of plastic, melts. 900$ plus labor you are good for another 200 hours.

Sure the Bendix mags were more expensive but I never spent any shop time diagnosing a starting or running problem, nor incurred a breakdown away from home.   These boards are full of pilots who spent thousands trying lots of things only to find out the Slick mags were bad.  A friend of mine actually spent weeks disgnosing , and finally overhauled his engine because the #4 cht couldn't be kept below 450 and come to find out it was a new slick mag installed a few hours before, that was the cause.  

[mike_elliott]

12 hours ago, M20Doc said:

I have a pair of those with 8 wires each.  Some Piper 180 Arrows had 1200 series mags as well.

Clarence

Good heaven's Clarence....Just how many Labatts' blues does it take to change all the plugs in that Commanche?

[1524J]

9 hours ago, d0tnet said:

Ive been the told this was due to improper tightening of the mag clamps and should be a non issue if properly torqued etc since there is a nylon lock nut being used. Even still, I constantly check the security of the clamps.

Has anyone used replacement hardware with crush washers and/or safety wired the nuts?

My mag is at Select aircraft services now. I bought new clamps, lock washers, nuts and gasket. When I pulled the mag I had the correct clamps installed already so I guess I've got an extra set of clamps if someone needs them.I'll also add these as a backup per the suggestion of a wise Mooney Space contributor. 

https://www.aircraftspruce.com/catalog/hapages/ms27151palnuts.php?clickkey=1371953

[nels]

What exactly is checked or what is the maintenance done during a 500 hr inspection of the Original Bendix style mags? Is there a typical wear item of which I should be aware?

[MB65E]

Usually, points, coils, for sure. Bearings and gears if needed. Internals cleaned and lubed. 

At 250hrs on turbo applications I can notice Slick mags start falling off with their performance. 

I like the Bendix I have on my E.

However, I  have not had too many issues with slicks that are properly overhauled. New out of the box Slicks?....many problems. Maybe close to 50% out of the box failures. With properly overhauled probably close to 99% realibility. This is out of 75-100 mag changes...

-Matt