K Magneto failed at BJC

[willerjim273]

Hello all. 

I have a 1980K. Yesterday the right mag gave out. Completely. On runup it acts like a total shutdown. Mechanics are looking at mag as cause. I am thinking switch as just had avionics work done. But they told me that unless grounded, the mag will produce spark....period as a rule cannot stop it. You are saying that something has to go back to the switch first? I also noticed that my headset connector plate down near left knee was a little bent after work. Seems like any time a mechanic gets near that plane, suddenly something goes wronger-er.  2 months ago after a different shop installed an Aerospace Logic MP/FF gauge- (absolutely awesome), my intercom switches ended up reversed ( Isolate/all and mono/stereo) AND I looked down as egressing and there is a part of a wiring harness clam laying on the carpet. Also the bottom cam locks disappeared- gone. What? Not going back there. Never had any problems like these at Arapahoe Aero with Scott. But then again, I did experience less money there.........get what you........

 

Anyhow, IF WIRES NEED TO GO TO SHITCH THEN BACK TO MAG, anyone give me a clue on what to look for? Try new /diff switch. ?? 

 

thanks Much

 

btw, spent most of yesterday BJC-FNL-KXY. Ipad traffic looked like a beehive. BJC tower finally said- No new calls extend dwind". Super busy. I do not get it how busy it was. You think it is pent  up covid? Every retailer Depot, Wally, etc says they are getting slammed, ??

 

Thanks

[EricJ]

It can be easily isolated between the mag and the switch by disconnecting the p-lead at the magneto.   If it still won't run on that mag, then it's the mag.   If it does run, it's the wiring between the mag and the switch or the switch, which can also be easily isolated.

There are some Bendix mags that have to have a p-lead adapter inserted when the p-lead is removed to prevent it from grounding internally, but your mechanic should have that.

[Guest]

A few minutes with the top cowl off and a multi meter should tell you if the “P” leads are shorted to ground when the switch is “on”

I believe the TSIO-360 will have Slick magnetos.

Clarence

[bradp]

If you ever disconnect your P lead treat your prop as if it were a loaded gun.  It’s hot.  

[Pierre07]

Hi,
I have an 81 K and I had the same exact thing happen 6 months ago, 2 flights after annual.
It was dying instantly as soon as I would turn the switch to right mag during runup.
Everything perfect the flights before. After couple hours of troubleshooting, I decided to take it out and open it. Here’s what it looked like, engine had 1050hrs at the time.

So I ended up changing it, and the left one did the same thing 3 months later.


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[EricJ]

1 minute ago, Pierre07 said:

Everything perfect the flights before. After couple hours of troubleshooting, I decided to take it out and open it. Here’s what it looked like, engine had 1050hrs at the time.

Had it been inspected within the last 500 hours?

 

[Pierre07]

Yes, 2 years (100hrs) before and wasn’t showing anything.


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[carusoam]

Nylon gear in an Ozone environment...

The natural color of nylon is whitish...

The oxidized embrittlement color of nylon is beige towards brown depending on how oxidized the surface gets...

The more oxidized the surface gets, the more brittle the teeth become...

See how many hours this gear has on it... was it changed during the last OH?

PP thoughts only, not a fan of some plastics subjected to O₃.

Best regards,

-a-

 

Another mag issue with a plastic gear can be found here...

 

[EricJ]

22 hours ago, Pierre07 said:

Yes, 2 years (100hrs) before and wasn’t showing anything.

Did whoever inspected it check the color or just look for cracks, etc.?

Because...

59 minutes ago, carusoam said:

Nylon gear in an Ozone environment...

The natural color of nylon is whitish...

The oxidized embrittlement color of nylon is beige towards brown depending on how oxidized the surface gets...

The more oxidized the surface gets, the more brittle the teeth become...

See how many hours this gear has on it... was it changed during the last OH?

PP thoughts only, not a fan of some plastics subjected to O₃.

Best regards,

-a-

The one in the pic is pretty dark.   I suspect it probably should have been changed out at the last inspection and wasn't.

 

[Pierre07]

That was 2 years ago and I wasn't the owner at the time so I can't be 100% sure, I can't even tell if they really opened it or not.

the color also hit me pretty bad when I opened it.

One thing I know now is that they are both new and will be inspected correctly as I do pretty much everything myself with my A&P.