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Slick Magneto major failure

Bill.Peyton

Well Known Member
In the process of my annual I noticed the timing of my left and only magneto had drifted 5+ degrees. This magneto was purchased from a VAF'r and had been removed from a new engine with only a few hours on it. It now has accumulated around 240 hours total hours. It should be noted that the mag drop was becoming a bit more than usual, around 150 rpm. The other ignition is an electroair, which has little if any drop when the mag is switched off. The Slick 6383 magneto is a retard breaker mag, with a slick start module. The plug wires were replaced with the mag as were the plugs replaced with fine wire REM38S. This is a IO540 D4A5. Below are the photos. I also attached a photo of the a cap and rotor from a 1000 hour mag for comparison. As you can see, the coil has overheated evidenced by the bubbling of the exterior. The rotor actually has a hole eroded completely through.



The only thing I can come up with for this type of damage, it that the slick start module is continuously running due to a key switch failure. I have not tested the switch yet to confirm.


Any thoughts on the failure mode
 

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I've opened up mags and found them more destroyed that this due to carbon dust arcing. Not saying this is the case here but I would test all of your leads with lead tester.
 
The only thing I can come up with for this type of damage, it that the slick start module is continuously running due to a key switch failure. I have not tested the switch yet to confirm.

Any thoughts on the failure mode

On my RV-10 Slick Start installation (driving a Bendix mag, so maybe there are differences from your installation) the Slick Start Vin line is connected to the starter relay output. So Slick Start is not powered except when the starter relay is activated. My Slick Start installation documentation has bold text saying "SlickSTART should only receive power when the starter is engaged."

Attached are my notes from my installation in about 2009.
 

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You don't need the slick start or the retard points in the mag if you start on the Electroair.
 
I just looked at my installation and see that you are correct, in that the slick start module derives it’s power from the starter terminal on the start solenoid. So that is not the issue. Bob, I figure the module is there, so why not use it during starting? I use both the electroair and the slick start during starts and it has worked great for 1000 plus hours. Hot starts are a non issue.
My guess is a totally shorted plug caused the arcing. I’m going to test them all today. Also going to test the new plug wires. The plugs looked clean when I pulled them yesterday, so no smoking gun yet.
Champion aerospace no longer answers their phones. You have to fill, out a form online to get them to respond. Maybe time to replace mag with something else!
 
I would suggest that possibly there is too much resistance in the wires or plugs, causing difficulty for the spark to jump the gap in the cap/rotor. Slick has also had some quality control issues with the rotor and wonder if that is the cause here. Definitely not normal. I just did IRANs on two 6 cyl slicks with 500 hours and the cap/rotor looked nothing like this.

Larry
 
Larry The cap sitting in the photo next to the destroyed cap, has 1000 hours on it. It's the same mag P/N and was removed from service to install this new one, which I purchased from someone who removed it from a factory engine (for a good price.) It was cheaper than purchasing the 500 hour kit!


An open plug wire would cause arcing everywhere, with no where for the energy to go. Slick did have an issue with the rotor attachment, while it does not appear to be loose, its one of those things I am going to check today.
 
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