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Magneto Maintenance

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Magneto Maintenance

So I've pulled the mags on the Bearhawk as they are past due for a 500 hour inspection. My initial thought is to IRAN them with a local A&P looking over my shoulder and put them back into service. They are Bendix S200 SOS mags (S6RN-200 and S6LN-204). Estimated cost if they only need points is about $200 in parts and another $100 or so in labor if I do the work and that is the total for both mags. I'm comfortable doing the work myself with A&P guidance.

However, if we get into this and find more, I'm wondering if it is better to send them out for repair or do an exchange on them? Or is it worth just having them overhauled for longevity to begin with?

Aircraft Magneto Service estimates overhaul costs of $525 per mag plus shipping both ways.

Airmark Overhaul is saying $537 per mag less $150 core charge for $387 per mag total plus shipping both ways.

What do the A&P's on here recommend? I'm after the best overall value and total price is secondary.

Thanks,
Mike
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Re: Magneto Maintenance

Mine are turning into P-mags when overhaul time comes...
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Re: Magneto Maintenance

CamTom12 wrote:Mine are turning into P-mags when overhaul time comes...



That is a great option and I would love to do the same. I've had high hopes for about 7 years that they would finally produce a 6-cyl version but after being told it is only a few months away for the last so many years, I've resigned myself to continued use of ancient technology :(.
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Re: Magneto Maintenance

blackrock wrote:
CamTom12 wrote:Mine are turning into P-mags when overhaul time comes...



That is a great option and I would love to do the same. I've had high hopes for about 7 years that they would finally produce a 6-cyl version but after being told it is only a few months away for the last so many years, I've resigned myself to continued use of ancient technology :(.


Shoot, I forgot they didn't do 6-cyls... That stinks.

Unfortunately I don't have any advice for the mag work, I've never opened one.
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Re: Magneto Maintenance

Mike,

Send em out to Aircraft Magneto Service. They are really good and worth the extra dough.
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Re: Magneto Maintenance

If you've got the tools (timing plate, pullers, etc.) and reference material (current manuals, SB's, AD's) go for it. It's not rocket science, but without the tools, you're spinning your wheels to get it done right. We always did ours when I was younger and working in a repair station, but anymore, unless it's my own, I send them out.
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Re: Magneto Maintenance

An A&P is sort of a jack of all trades, but a mag shop just does mags.
I would be inclined to go with the specialist. Cliff at Aircraft Magneto Service really knows his stuff, I'd recommend him in a heartbeat.

They were on the field at KBFI for a long time, then moved the shop to Cliff's home on Bainbridge Island a number of years ago. That eventually got too populated for him, so last year they moved the whole kit and caboodle to Montana. Not too long before they moved, I carried my mags down there for a "500 hour inspection"-- actually more like a 1200 hour inspection. Cost me more than I'd planned on, $1250 with tax, but now I know they're good to go for a good long time.

The way Cliff explained it to me, when they do an "inspection" they replace whatever needs replacing. But an "overhaul" must be done per the mfr's overhaul manual which specifies a lot of stuff to be replaced, which may or may not need replacing. So an inspection is just a cost-effective version of an overhaul. 500 hours seems to me to be pretty low time for an inspection, but then again the longer you wait the more parts will probably need replacing.
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Re: Magneto Maintenance

I am not an A&P. However, I agree Aircraft Magneto Service is the way to go especially if you do not know the full history/service of the mags. They also check my harness at no charge!! Once done they test the mags in a heated cell to ensure you/they won't have problems when sent back.
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Re: Magneto Maintenance

I recently listened to Mike Busch's webinar on mags. Basically his advice is to only overhaul mags at engine overhaul. At each 500hr inspection send them to a mag shop for an IRAN.
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Re: Magneto Maintenance

I see a lot of operators trade them for new Slicks. I always liked the Bendix with Slick harness.
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Re: Magneto Maintenance

I'd say do them yourself. It's not rocket science. Find a manual and go to town. I think you'll find they are so stupid simple that you'll be glad you took it on yourself.
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Re: Magneto Maintenance

gbflyer wrote:I see a lot of operators trade them for new Slicks. I always liked the Bendix with Slick harness.


I traded in a set of good Bendix for new Slicks when I had my C170 engine OH'd about 15 years ago. Didn't know any better then, but I would never do that now. IMHO a Bendix throws a lot hotter spark than a Slick, and will fire an iffy plug when a Slick won't. I think a Bendix could get a spark out of a carrot, if you could just figure out how to attach the lead.
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Re: Magneto Maintenance

gbflyer wrote:I see a lot of operators trade them for new Slicks. I always liked the Bendix with Slick harness.


I've always done it the other way around.

Needed to do the 500hr on the slicks that came on my 185, just traded them in for a set of OHed bendix complete with new harness.

Heard some folks say they'd rather fly high time bendix compared to new slicks. I'm not sure about all that, but on my own plane decided to spend the extra $$ and swap over to bendix
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Re: Magneto Maintenance

The shop I worked part time at, which has contracts for various "Organizations", uses:

http://www.aircraftmagnetoservice.net

Aircraft Magneto Service
Test, Repair, 500 Hour Inspection, Overhaul, Exchange
8171 Mullan Road
Missoula, Montana 59808
1-844-AMS-MAGS (1-844-267-6247)
406-543-0695
206-768-3099
Accounting Office 206-842-1619
[email protected]


...Per manufacturers service data.
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Re: Magneto Maintenance

AEROPOD wrote:I'd say do them yourself. It's not rocket science. Find a manual and go to town. I think you'll find they are so stupid simple that you'll be glad you took it on yourself.



I like that idea and agree they look fairly simple to IRAN or overhaul. I've got a PDF copy of the Bendix manual. The tools are listed in Chapter 10 but the exact ones listed will be hard to come by however it looks like substitutes would work. Do you know what specialty tools would be required? At a minimum it looks like an e-gap internal timing gauge, a mag timing light, multi meter, etc. Possibly a capacitor tester and a way to measure leakage rate?

This is the actual tool list and I'd like to know which tools are mandatory vs just nice to haves:

Image
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Re: Magneto Maintenance

BR, You asked what the A&Ps on here thought which is why I didn't give you my opinion. I think you should do it yourself under the watchful eye of someone you trust. I will be overhauling the mags for my plane myself. I can't imagine they are all that much different than tractor mags.
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Re: Magneto Maintenance

In the Part 135 and .gov operations unless our shop has an approved SOP, tools, test equipment (that is similar) to the approved manufacture's procedures, we send the accessories out to a shop that does. No choice. The FSDO will pretty much enforce it on our ramp. For Part 91 I am not sure how far an owner and A&P together can go. Personally, I have the manuals available, no big deal but, the tools and test equipment no.
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Re: Magneto Maintenance

Thanks for all the input everyone. For now, I've put the mags back on after opening them up and checking points, shaft end play, wiring, cases for cracks, etc. In the short to medium term, I'd like them to be gone through more thoroughly and the points replaced. Doing it myself has the most appeal, and I'm willing to buy the tools and work with an A&P/IA to get it done, but like has been said on here several times, most just send them out. They did it in A&P school and maybe a few times afterwards, but I don't know any one who has the tools.

Still might wind up sending them out if I cant get the needed tools. I've found a few on line, but certainly not all the ones listed. I already have the timing light and multimeter.

whee wrote:BR, You asked what the A&Ps on here thought which is why I didn't give you my opinion. I think you should do it yourself under the watchful eye of someone you trust. I will be overhauling the mags for my plane myself. I can't imagine they are all that much different than tractor mags.


Thanks Whee,

What model are your mags? I'd be glad to loan any special tools I've acquired when your ready to do yours.
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Re: Magneto Maintenance

Thanks BR. My mags are Bendix S6LN-25.
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Re: Magneto Maintenance

Hey Mike, it's not rocket science. I know you have the ability!

Aircraft tool sells a tool kit but it will cost you.

http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=T100

Might not be worth it only to use once in a while though???
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