Bendix Mag Service
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Bendix Mag Service
N888A's Bendix Mags have attained the 500 hour mark since the last inspection and the AD now requires them to be checked for the impulse coupling "pin" wear. My AI has suggested I take them to a local shop and have that checked as well as having the mags gone through to check for any other wear related items and to be properly lubercated. We have a trusted shop in the area who has advised his charge to go through each mag is $250.00, which presumably includes coils, points, condensers, etc., excluding gears and other items that might be worn to a point of needing replacement. Does this price seem in line with what others have paid for similiar mag work?
OLE POKEY
170C
Director:
2012-2018
170C
Director:
2012-2018
I just did it.
If your pins are look good you still have to revisit the AD every 100 hr.
If you replace just the AD parts for both mags I think it was $300 and that gets you to inspect every the pins 500 hr, that what I did. But in hindsight I should have gone for the new Mags Make sure that you understand your Options
If your pins are look good you still have to revisit the AD every 100 hr.
If you replace just the AD parts for both mags I think it was $300 and that gets you to inspect every the pins 500 hr, that what I did. But in hindsight I should have gone for the new Mags Make sure that you understand your Options
Re: Bendix Mag Service
I'll have the dig the bill/work order out to get an exact figure, but170C wrote:N888A's Bendix Mags have attained the 500 hour mark since the last inspection and the AD now requires them to be checked for the impulse coupling "pin" wear. My AI has suggested I take them to a local shop and have that checked as well as having the mags gone through to check for any other wear related items and to be properly lubercated. We have a trusted shop in the area who has advised his charge to go through each mag is $250.00, which presumably includes coils, points, condensers, etc., excluding gears and other items that might be worn to a point of needing replacement. Does this price seem in line with what others have paid for similiar mag work?
last summer I paid in the low $300 range for the AD inspection
and IRAN of both Bendix mags. This was through AvStar Aviation
in Puyallup, Washington State.
Bela P. Havasreti
'54 C-180
'54 C-180
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Bruce Fenstermacher
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What AD are you talking about? AD 96-12-07 has been superceded by AD 2005-12-06. 2005-12-06 does does not apply to our aircraft. UNLESS of course you have an IO540 installed. 
Of course it you haven't looked at and inspected and maintained any magneto regardless of its make and model for 500 hours it's probably time to do so.
Of course it you haven't looked at and inspected and maintained any magneto regardless of its make and model for 500 hours it's probably time to do so.
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
For anyone contemplating changing out from Bendix mags to Slicks, I did this at OH a few years ago & now kinda wish I hadn't. I think the Slick doesn't oput out as hot a spark as the Bendix. I had to replace the plugs (Champions) a few years ago after only about 450 hours cuz the resistors had built up too much... resistance. They looked great, just woildn't fire. The Slick mags were checked & met specs. Now with about 425 hours on some Autolite plugs, I'm getting that hard to start sympton going on again, and suspect that I'll be spending a few hundred bucks on new plugs again real soon. BTW the plugs (both now & last time) looked great, almost zero erosion. My prior set of Champions worked fine with my old Bendix mags, even after who knows how many hours on boith plugs & mags.The center electrodes on the plugs were eroded down to where they were football shaped.
Eric
Eric
Thanks for posting this Bruce. I was 3/4 of the way through anN9149A wrote:What AD are you talking about? AD 96-12-07 has been superceded by AD 2005-12-06. 2005-12-06 does does not apply to our aircraft. UNLESS of course you have an IO540 installed.
Of course it you haven't looked at and inspected and maintained any magneto regardless of its make and model for 500 hours it's probably time to do so.
annual and didn't know this AD had been superceded (no
doubt my IA would have caught it during the paperwork / logbook
entry phase of the annual).
In any event, I had just complied with the AD last spring (a little
over 125 hours ago) so there was at least 2.5 or so year's worth
of flying to go before the next (previsouly required) inspection.
I agree it might not be a bad idea to have any set of mags looked
over by the Mark I eyeball every 500 or so hours.
That being said, Mike @ AvStar in Puyallup told me most of the Bendix
mags currently in service already have the latest/improved parts
in them, and the situation that created the original AD in the first
place is generally not an issue for most of the regularly flown/mainted
fleet out there.
Kudos goes to the feds (did I say that?) for using real world metrics
to supercede the AD based (I assume) upon the lack of issues in the
fleet (with the exception of IO540-powered aircraft).
Which drives me to the next question:
The feds are pretty good about sending notifications out for
ADs that affect whatever aircraft we have recorded /
registered with them. Wouldn't it be nice if we got a notice
when an AD was no longer applicable for said registered aircraft?
Or did we get such a notice and I missed it? (I did move within the
last year).
Bela P. Havasreti
'54 C-180
'54 C-180
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russfarris
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Metal Master
- Posts: 526
- Joined: Thu Dec 02, 2004 1:52 am
[quote="N9149A"]What AD are you talking about? AD 96-12-07 has been superceded by AD 2005-12-06. 2005-12-06 does does not apply to our aircraft. UNLESS of course you have an IO540 installed.
Of course it you haven't looked at and inspected and maintained any magneto regardless of its make and model for 500 hours it's probably time to do so.
For years know I have felt that once the parts concerned in AD 96-12-07 were replaced with the snap ring impulse coupling that the AD should no longer apply but an AD is an AD. I always consoled myself as an IA that at least it caused people with these mags to open them up and look at them every 500 hours. Where with Slick mags I would occasionally get an airplane that had never had the mags looked at. Sometimes they would not have been looked at for over a 1,000 hours. People that have Slick mags have often thought that this is a benefit in that they do not have to have the mags looked at. You would not believe the things I have found wrong inside any mag’ after 500 hours. But I just recently found out this was not necessarily true.
I just had the Bendix mags for my 170 gone through. The Impulse couplings had been replaced with the latest Snap ring impulse coupling but none of the rest of the mag had had service. It had Plastic drive gears that I have never even seen in a Bendix mag before and was supposed to have been replaced years ago with a steel gear. All of the screws that were in the mag housing have lock washers, which had lost their spring tension. (These washers are trapped on the screws). It cost me just over $450 dollars in parts to do both mags. That’s at my cost no mark up on the parts and no labor. If I had had to pay to do all of this work the mag housings were stripped, alodined, and painted new bearings installed and all new hardware. Points replaced new distributor gears and distributor block the price of parts would have been $562.50 and the Labor around $360 for 6 hour labor estimated. Total $922.00 plus tax ends up being $1,003.68 cost/ $501.84 per magneto. If the mags had been regularly maintained the cost would not come to this much. I have found that if three major parts have to be replaced in any magneto. Say the coil, Distributor block and impulses coupling then you are better off getting a new magneto from a cost standpoint. But on the other hand if you have some one you trust to repair the magneto then you might be better off in the long run than getting something from Kelly Aerospace. I would recommend having the lock washers on the screws looked at it. It is a small item but the screws will back out if the lock washers are flat and lost there sprin tension.
So in the end I think that having this AD basically go away for most of us, is both a good thing and a bad thing. Perhaps the reason there have not been in failures of these mags requiring and AD any longer is more because they have been being looked at as apposed them not having been looked at.
Of course it you haven't looked at and inspected and maintained any magneto regardless of its make and model for 500 hours it's probably time to do so.
For years know I have felt that once the parts concerned in AD 96-12-07 were replaced with the snap ring impulse coupling that the AD should no longer apply but an AD is an AD. I always consoled myself as an IA that at least it caused people with these mags to open them up and look at them every 500 hours. Where with Slick mags I would occasionally get an airplane that had never had the mags looked at. Sometimes they would not have been looked at for over a 1,000 hours. People that have Slick mags have often thought that this is a benefit in that they do not have to have the mags looked at. You would not believe the things I have found wrong inside any mag’ after 500 hours. But I just recently found out this was not necessarily true.
I just had the Bendix mags for my 170 gone through. The Impulse couplings had been replaced with the latest Snap ring impulse coupling but none of the rest of the mag had had service. It had Plastic drive gears that I have never even seen in a Bendix mag before and was supposed to have been replaced years ago with a steel gear. All of the screws that were in the mag housing have lock washers, which had lost their spring tension. (These washers are trapped on the screws). It cost me just over $450 dollars in parts to do both mags. That’s at my cost no mark up on the parts and no labor. If I had had to pay to do all of this work the mag housings were stripped, alodined, and painted new bearings installed and all new hardware. Points replaced new distributor gears and distributor block the price of parts would have been $562.50 and the Labor around $360 for 6 hour labor estimated. Total $922.00 plus tax ends up being $1,003.68 cost/ $501.84 per magneto. If the mags had been regularly maintained the cost would not come to this much. I have found that if three major parts have to be replaced in any magneto. Say the coil, Distributor block and impulses coupling then you are better off getting a new magneto from a cost standpoint. But on the other hand if you have some one you trust to repair the magneto then you might be better off in the long run than getting something from Kelly Aerospace. I would recommend having the lock washers on the screws looked at it. It is a small item but the screws will back out if the lock washers are flat and lost there sprin tension.
So in the end I think that having this AD basically go away for most of us, is both a good thing and a bad thing. Perhaps the reason there have not been in failures of these mags requiring and AD any longer is more because they have been being looked at as apposed them not having been looked at.
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Interesting that this AD was completely superceded by another new AD in 2005. I'm just now looking at my file copy of 96-12-07, at the beginning it sez it supercedes AD 78-09-07 R3. Wish they'd make up their mind!N9149A wrote:What AD are you talking about? AD 96-12-07 has been superceded by AD 2005-12-06. 2005-12-06 does does not apply to our aircraft. UNLESS of course you have an IO540 installed.
I agree with Bela, it'd be nice if they sent out a notice when an AD goes away or is superceded. I guess you'd only have gotten one in this situation if you had a 540. (but I always get an "uh-oh" feeling whenever something shows up in the mail with an FAA return address! )
Parts cost: FWIW, it seems like Slick parts cost more than Bendix parts when I've checked them out in the catalogs. Another argument for Bendix.
Eric
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Robert Eilers
- Posts: 652
- Joined: Sat May 08, 2004 12:33 am
Bendix Magneto Service
The quote of $250 is consistent with what Savage Magneto, Hayward, CA quoted me not long ago to rebuild the Isemann Mags on my Champ. That was $250 each.
used to be when they'd revise an AD it just got a revision number, like R1, R2, etc. now it often seems that it just becomes a brand new AD with each change.
maybe the amount of info changing has something to do with it, seems like no rhyme/reason sometimes.
my mags are so old that they still have phenolic (not plastic) gears in them, and although they are in great shape and everything has been done at the proper times to them, I think the next time I look in them I'll just get remans - time to move up a century
maybe the amount of info changing has something to do with it, seems like no rhyme/reason sometimes.
my mags are so old that they still have phenolic (not plastic) gears in them, and although they are in great shape and everything has been done at the proper times to them, I think the next time I look in them I'll just get remans - time to move up a century
'56 "C170 and change"
'52 Packard 200
'68 Arctic Cat P12 Panther
"He's a menace to everything in the air. Yes, birds too." - Airplane
'52 Packard 200
'68 Arctic Cat P12 Panther
"He's a menace to everything in the air. Yes, birds too." - Airplane
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David Sbur
- Posts: 43
- Joined: Sun Sep 26, 2004 10:43 pm
FWIW on my last AD for my Bendix mags regarding the impulse couplers, they were servicable but what got our attention was the drive gears to the engine being shot! Glad I pulled the mags to comply with the AD and to get nosey with them and check things out. Made me learn how to time mags and troubleshoot too, my IA appreciates that!
My mags have been serviced/maintained well over the years and AD's and service letters complied with. Still, am anxious to learn how to overhaul-fortunately have an IA with the bench test gear and proper equipment to 'replace' parts (never did understand that stuff about overhaul vs. repair/replace).
My mags have been serviced/maintained well over the years and AD's and service letters complied with. Still, am anxious to learn how to overhaul-fortunately have an IA with the bench test gear and proper equipment to 'replace' parts (never did understand that stuff about overhaul vs. repair/replace).
Repair/replacement is what most folks do. An overhaul would also require the RE-magnetizing of the magnets, and many other details specified in the overhaul manuals. It's a fun tour to see a genuine overhaul facility do their thing. Savage Magneto in Oakland, CA used to give tours, if anyone wishes to see one. (Sorta reminded me of old horror films tho', to see a magneto firing up a wall-board full of spark-gap testors. The racket was amazing.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Robert, a very knowledgable (and opinionated!) friend of mine sez that Eisman's are the best mag ever made. Hang onto them, they're keepers!
Russ, I think spark plugs *should* last 1800 hours, same as an engine-- put in new plugs at overhaul, replace them at TBO! Along with the other "accesories".
The plugs that were in this airplane when I bought it were replaced due to electrode erosion after flying behind them for over 500 hours, and they were far from new when I started. I just looked back thru the logbook, I found where 6 of the plugs had been replaced 1100 hours before I replaced all of them. Now we're talking!
This is more than I can hope for, I know, but 400-500 hours service life seems a bit short. I fly a lot, 160-170 hours a year, so we're talking about spending $200-250 for new plugs every 2-1/2 or 3 years But that's life, I guess-- if the plugs are no good, they're no good. My point being that either that first set of plugs was exceptional, or that the old bendix mags put out a hotter spark. Or both.
Eric
Russ, I think spark plugs *should* last 1800 hours, same as an engine-- put in new plugs at overhaul, replace them at TBO! Along with the other "accesories".
The plugs that were in this airplane when I bought it were replaced due to electrode erosion after flying behind them for over 500 hours, and they were far from new when I started. I just looked back thru the logbook, I found where 6 of the plugs had been replaced 1100 hours before I replaced all of them. Now we're talking!
This is more than I can hope for, I know, but 400-500 hours service life seems a bit short. I fly a lot, 160-170 hours a year, so we're talking about spending $200-250 for new plugs every 2-1/2 or 3 years But that's life, I guess-- if the plugs are no good, they're no good. My point being that either that first set of plugs was exceptional, or that the old bendix mags put out a hotter spark. Or both.
Eric