Slick Mag Installation Problem

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gobrien
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Joined: Sun May 19, 2019 11:36 am

Slick Mag Installation Problem

Post by gobrien »

Hi All,

Having sent my Bendix mags for inspection, it turned out that they needed complete overhaul. The harnesses were shabby too, so I decided to bite the bullet and order the Slick Kit for the O-300: K6327R-40

I have successfully installed the gear onto the magnetos. The mags insert into the accessory case and the gears engage. However, I was unable to get the clamps to seat. As you'll see in the attached image the radius on the clamp perfectly matches the magneto housing but the hole position in the clamp does not appear to match the studs. It looks to need about 1mm (40 thou) of additional clearance to make this work.
image1118.png
image1118.png (206.14 KiB) Viewed 2545 times
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Click image to Zoom!

I could drill out the holes or hand file them to become slots and make it work. However, as this is a kit specifically for this engine I want to get advice first and make sure I'm not missing something.

Has anyone installing Slick Mags seen this before?

Is it normal to have to modify these clamps or are there special clamps for the O-300?

Thanks,

Gareth.
1948 170 Project (N4180V) now EI-AEN SN:18513 - Dublin, Ireland
https://www.taildragger.eu/
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n2582d
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Re: Slick Mag Installation Problem

Post by n2582d »

Gareth,
It looks like you have the lower clamp past the top lip of the magneto. Will the top clamp not fit if you pull the mag out slightly, position the clamp over the base flange, and then onto the stud?

Aircraft Spuce has this link to Champion’s L-1318H Consolidated Application Data guide. There, in the Appendix page A-5, is the following listing for your K6327R magneto kit:
Click to enlarge
Click to enlarge
The M3520 clamp kit is a stamped and bent clamp as seen here. Aircraft Spruce’s Q&A conflicts with this as they write:
Click to enlarge
Click to enlarge
Aircraft Spruce’s p/n 08-03712 crosses to Champion p/n K3328, also a stamped part as seen here:
4C9EDD75-782F-4033-8642-648D06D68B76.jpeg
Available for $10 here. As your clamps are either cast or machined they look more like M3784/K3784 clamps - the only such clamps Aircraft Spruce shows of that style. But they have chamfered corners which yours don’t appear to have.
CEA9AB6C-81B4-4309-936D-278A7C250F33.jpeg
Gary
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gobrien
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Re: Slick Mag Installation Problem

Post by gobrien »

Thanks Gary!

That's some excellent dot joining. I sent a support request to Champion Aero (Slick) yesterday and now to Aircraft Spruce as I've not heard anything from Slick. I'm adding this info to both and I may go ahead and order the $10 ones from eBay in the hopes of getting things moving!

I also tried the mount and wiggle approach... No bueno. It's jammed in the photo.

Gareth.
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1948 170 Project (N4180V) now EI-AEN SN:18513 - Dublin, Ireland
https://www.taildragger.eu/
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Bruce Fenstermacher
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Re: Slick Mag Installation Problem

Post by Bruce Fenstermacher »

Gareth, I would double check that you have the correct cotter and it is installed correctly. The nut your using also looks unusual. How you have the cotter installed is incorrect on most Slick mag installations. The correct cotter has one short leg which is placed at the top and a single cotter leg is bent down. No leg is bent up over the shaft. Like I said, this may be correct for your installation but seeing it raises hair on the back of my neck.

And no, it is not usual to have to modify the clamps. I've never had to. However if a little file work would make it work, and you find no other reason it wouldn't fit, I might be inclined to "finish" the hole to work for you.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
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gobrien
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Re: Slick Mag Installation Problem

Post by gobrien »

Thanks Bruce,

I put the cotter pin on wrapped over the way they were on the Bendix; there is nothing behind that they could foul on. However, I'll replace them the other way for the sake of your neck hair! :D The posh flangey nut came with the kit!

I have a support call into spruce, so we'll see how that goes. I would have to file a good 30 thou off each clamp hole them to make them work, which just doesn't seem right!
1948 170 Project (N4180V) now EI-AEN SN:18513 - Dublin, Ireland
https://www.taildragger.eu/
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gobrien
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Re: Slick Mag Installation Problem

Post by gobrien »

For reference, in case anyone else runs into this.

In consultation with Champion I drilled and reamed the holes in the clamps out to 10mm. This gave adequate clearance to install the mags. It turns out the slots in the Bendix mags are 9.7mm wide for a 5/16" stud allowing about +/- .9mm tolerance. The K3520 clamps are very nice machined parts, but the hole is about 8mm leaving almost zero clearance. The stamped clamps that Gary mentioned may also be used and they have more tolerance than the machined ones in the kit. I suspect more than one A&P has solved this by one of these methods in the past!

I did reinstall the cotter pins that Bruce noted didn't look like he's seen previously - however with the flanged castle nut that Champion supplies there is no way to bend the pin down, so although I changed out to using the pin in the kit, I still had to bend it up and over as seen in the previous post. I don't like the fancy flanged arrangement as one of the shafts was not drilled in the right position and it was a major drama to get enough torque on the nut while still lining up the cotter pin hole with the castellation. I would prefer a suitably sized plain washer and "normal" castellated nut which would be easier to adjust for alignment.

Cheers,

Gareth.
1948 170 Project (N4180V) now EI-AEN SN:18513 - Dublin, Ireland
https://www.taildragger.eu/
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