Slick Mags, a tutorial

[TangoWhiskey]

Parts of a TCM mag are reasonable in price and the mag can be rebuilt cheaper than the slick TCM price list:

http://www.chiefaircraft.com/aircraft/ignition-system-mags-plugs/tcm-bendix-magneto-parts.html

Slick price list.
http://www.chiefaircraft.com/aircraft/ignition-system-mags-plugs/slick-magneto-parts.html

Wow, that was telling!!

 

[flyingriki]

I took the forum with Joe Logi from Champion at Oshkosh. He runs the magneto service department there, write the bulletins and runs the website. Probably, after Mike Busch, the most informative talk I ever heard. And a really nice guy. He encourages anyone with issues to contact him at: slicksupport@championaerospace.com

Also spent 45 minutes with him at the booth and he opened up a used mag I had purchased to use as a demo. Turns out it was in great shape, all the minor checks he does were good, E-gap good and points good. Replaced the center brush anyway. Gave me a couple little tools and told me which others to pick up so I can do my own inspections now. Cost practically nothing for parts, 20 minutes including explanations and anecdotes and good to go another 500 hours. Really great guy and sold me on sticking with his products with his terrific customer service attitude.

Now, with a thorough understanding of the inside of a Slick and the inspection process/ technique it's interesting to hear folk without this knowledge diss the product....

 

[Tom-D]

I took the forum with Joe Logi from Champion at Oshkosh. He runs the magneto service department there, write the bulletins and runs the website. Probably, after Mike Busch, the most informative talk I ever heard. And a really nice guy. He encourages anyone with issues to contact him at: slicksupport@championaerospace.com

Also spent 45 minutes with him at the booth and he opened up a used mag I had purchased to use as a demo. Turns out it was in great shape, all the minor checks he does were good, E-gap good and points good. Replaced the center brush anyway. Gave me a couple little tools and told me which others to pick up so I can do my own inspections now. Cost practically nothing for parts, 20 minutes including explanations and anecdotes and good to go another 500 hours. Really great guy and sold me on sticking with his products with his terrific customer service attitude.

Now, with a thorough understanding of the inside of a Slick and the inspection process/ technique it's interesting to hear folk without this knowledge diss the product....

When there is nothing wrong or worn out, any thing is cheap to fix.

When a slick has a need for a distributor block and rotor plus points and cam. it is cost prohibited to overhaul it your self.

I hope you are an A&P.

 

[flyingriki]

When there is nothing wrong or worn out, any thing is cheap to fix.

When a slick has a need for a distributor block and rotor plus points and cam. it is cost prohibited to overhaul it your self.

I hope you are an A&P.

It had over 1200 hours on it. I think any mag in that shape, with those hours, is doing pretty good. I may be wrong.

Of course if everything is wrong and worn out the overhaul will get expensive.......duh!

And I should be an A&P exactly why....

 

[Tom-D]

To ask that question you must be an EXP operator.... ?

 

[Tom-D]

The Fix:

I read out the Mag Switch, it read a high restance short to ground on all positions, I removed it and cleaned it tested it and replaced, that helped but we still had a large mag drop.
I read out the "P" leads and found an intermittent open in the off position or when I disconnected both ends they would open the continuity when they were bent. I built a new set and replaced, that helped but we still had a high mag drop.
I removed and cleaned all 8 iridium plugs, that helped too but we still had a high mag drop on the left.
I removed the high tension ignition harness and meggered the leads and found 2 bad leads, and replaced them, that helped too, but we still had a high mag drop on the left mag, I removed it and opened it up and showed you the pictures.
We ordered a mag conversion kit and received two mags and harness, and 8 new plugs ( champion REM40E) and replaced the whole ignition system.

$1825 for the kit, $500 labor, 30 for other parts.

we now have a 100/100 smooth mag drop

the plugs and left mag were at TBO for the engine. they did what they were designed to do.

 

[flyingriki]

"This message is hidden because Tom-D is on your ignore list."

I find this works great on certain folks that seem to know everything......

 

[alaskaflyer]

"This message is hidden because Tom-D is on your ignore list."

I find this works great on certain folks that seem to know everything......

Real classy. Wouldn't it be easier to simply exit a discussion that HE started if you don't like the way it's going?

 

[nepprimmer]

when looking at the rotor and distributor... what is considered normal wear.. does anybody have pics of yes these are ok to fly... no toss these too far worn

 

[NineThreeKilo]

Real classy. Wouldn't it be easier to simply exit a discussion that HE started if you don't like the way it's going?

Right!

Seems some people are very sensitive here, if they mentally can't handle to even look at a users post on some website.

Same great minds that "bleep"'out words on the radio and TV.

If one is that timid perhaps interaction with the outside world should just be completely avoided?

 

[flyingmoose]

Tom, what parts needed replaced that were more expensive than just replacing the mag. From your pics looks like points, cam follower, button? Did you go through that before just ordering new ones? Just curious.

 

[Silvaire]

Of course they are all owned by different companies now, TCM owns Bendix and I think Champion owns Slick but back about 30 years ago (and this is maybe the main reason many old mechanics don't like Slick mags) they had a marketing strategy that involved you getting a pretty good deal on two new Slick mags and harness providing you turned in your Bendix mags which they would destroy.

Personally I prefer the Bendix mags, they're better built and ultimately more rebuildable. Slicks use that little plastic breaker cam with very light weight points and don't have the internal safety feature that grounds them when the p-leads are disconnected like the Bendix. Overall they are just less stoutly built but this is not to say that Slicks are "junk" - they aren't, they're good mags and you can use them with confidence.

Both use the plastic looking distributor gears which can and do break, causing in flight magneto failure. They are one of the more critical parts and you can normally tell by the color how old they are. New gears have a greenish tint to them and the more yellowish/brown the gear looks the closer it is to coming apart. I believe all new gears are now date etched (at least TCM ones are) so the fact that you went 2400 hours without a problem does not tell you how close you may have been to having a failure.

 

[Dan Thomas]

Both use the plastic looking distributor gears which can and do break, causing in flight magneto failure. They are one of the more critical parts and you can normally tell by the color how old they are. New gears have a greenish tint to them and the more yellowish/brown the gear looks the closer it is to coming apart. I believe all new gears are now date etched (at least TCM ones are) so the fact that you went 2400 hours without a problem does not tell you how close you may have been to having a failure.

We regularly ran Slicks to 2400 hours, but in that period there was usually a bunch of work sometime after 1000 hours. Points and cam, at a minimum, and sometimes a distributor block and rotor and a new rotor drive gear. Never had any gears fail on the ones that went all the way to TBO, but did have plenty of quality-control problems, including one gearset that was chewing itself to pieces because the assembler at the factory hadn't pushed the drive gear onto the shaft all the way. Plastic dust everywhere. It would probably have failed if that dust hadn't fouled the points and alerted us to a problem.

Dan

 

[bnt83]

Coils die without warning in both bendix and slicks.


Don't forget the soft carbon brush ordeal that can lead to shorting and melting of the plastic parts of the distributor etc.

IMHO, 500 services just ensure that the mag makes TBO preventing a bad brush or excessive buildup of conductive materials from shorting the mag out and destroying the plastic stuff. Also, the e-gap setting will drift with cam wear etc. Rusty impulse springs don't fly either.


Bendix on the onther hand, I feel the bearings need to be greased at 500 hrs or 5 years, maybe more often than 5 years.

 

[Silvaire]

We regularly ran Slicks to 2400 hours, but in that period there was usually a bunch of work sometime after 1000 hours. Points and cam, at a minimum, and sometimes a distributor block and rotor and a new rotor drive gear. Never had any gears fail on the ones that went all the way to TBO, but did have plenty of quality-control problems, including one gearset that was chewing itself to pieces because the assembler at the factory hadn't pushed the drive gear onto the shaft all the way. Plastic dust everywhere. It would probably have failed if that dust hadn't fouled the points and alerted us to a problem.

Dan

Over the past five years or so the problems I've seen have all been with Slicks. The last one was on a fairly new Cessna Corvalis, the distributor gear lost a bunch of teeth for some reason. As I eluded to earlier, the color was yellowish brown despite not being that old. Someone suggested it was due to elevated ozone levels in the mag case due to the high altitudes this guy was normally flying at which I guess degrades the ventilation but these were pressurized so not sure if that's true. Another fellow with a 206 has had some chronic problems with his Slicks - almost like bad karma

I've got four Bendix S20's so I'm probably biased. I've recently gone through all of them and other than the seals I didn't have to replace anything. The cams and points, even the distributor block and gear were all acceptable. They are overall a more robustly built magneto.

 

[Dan Thomas]

Over the past five years or so the problems I've seen have all been with Slicks. The last one was on a fairly new Cessna Corvalis, the distributor gear lost a bunch of teeth for some reason. As I eluded to earlier, the color was yellowish brown despite not being that old. Someone suggested it was due to elevated ozone levels in the mag case due to the high altitudes this guy was normally flying at which I guess degrades the ventilation but these were pressurized so not sure if that's true. Another fellow with a 206 has had some chronic problems with his Slicks - almost like bad karma

I've got four Bendix S20's so I'm probably biased. I've recently gone through all of them and other than the seals I didn't have to replace anything. The cams and points, even the distributor block and gear were all acceptable. They are overall a more robustly built magneto.

The Bendix is a better mag, for sure.

High altitude causes problems. Most magnetos flying at those levels are pressurized off the turbo system. Air is a dielectric, and as it thins the distributor spark gaps can do some funny stuff, with flashover or something, and the engine can run poorly.

http://www.aviationpros.com/article/10388584/magnetos-under-pressure

Dan

 

[moonshine]

$800 for plugs? just curious, are there any less expensive options

Tempest fine wires. General opinion on the Diamond board - better results for less money ($65 or so a piece vs $95 for Champion)