Bad Mag Check

[Mconner7]

A friend has an RV-10 with slick mags. Apparently neither one is an impulse coupled mag but has start and run leads to the mag in addition to the P lead. It starts but run up shows that mag (left) to have failed. I know nothing about mags except for impulse and non impulse.

Mag related it is there a start box somewhere that may also cause this?

 

[Kyle Boatright]

If it has two mags and neither is an impulse coupled mag, the left mag is probably combined with a slickstart module.The slickstart, combined with the left mag, gives a very strong spark during the starting process.

I don't know of a failure mode of the slickstart that would result in a mag failure once the engine is running.

One thing to consider is that mags which combine with the slickstart have two sets of points - one normal set and one set that comes into play when you're starting the engine. Based on what you've said, it sounds like there may be a problem on the "normal" side of the left mag (not the starting circuit).

 

[BobTurner]

That left mag is called a ‘retard’ mag. Trace the extra wires coming out of it to find the slickstart module - typically mounted on the firewall. But, as Kyle said, it sounds like the problem is in the mag, not the slickstart.

 

[Mconner7]

Slick start to impulse.

I may just remove the slick start mag and replace it with an impulse mag? I have a couple in the shop that I pulled at 500 hours, might get him home.

 

[jrs14855]

Mag

Slickstart to impulse mag will require a spacer which in turn will probably require longer studs.
Best to repair or exchange the Slickstart.

 

[jrs14855]

Mag

Likely failure point is the "normal" breaker points.

 

[F1R]

The 6393 retard breaker mag uses a SLICK START module.

There are 2 sets of points. One for starting (that is retarded, connected to the slick start and active only when the starter is energized) The Second set of points is for running at the advance timing position.

YES the starting mag can start just fine, then the engine will run fine(on the RH mag) but the LH will show or indicate failed on a mag check, because the operating points and or related hardware have failed.

A bit tricky to understand, but the short version is exactly as jrs4855 said above "Likely failure point is the "normal" breaker points."

 

[BobTurner]

I may just remove the slick start mag and replace it with an impulse mag? I have a couple in the shop that I pulled at 500 hours, might get him home.

Be careful. There is an AD on the IO540/slick impulse mag combo requiring frequent inspections. Apparently some vibration harmonic in this engine does not get along well with the impulse mechanism. While ADs do not technically apply to EAB, I’d suggest caution.

 

[Mconner7]

Slick impulse spacer

Here is a picture of the spacer and the slick start magneto. I think the spacer looks right for the impulse mag.

 

[Mconner7]

Hopefully my spare mag will get him home. I would love any input from folks with one of the Slick Start mags.

1). Are they problematic or a good product.

2). Will I need to call my banker to have the old one overhauled?

3). Should we overhaul one of my spare impulse mags and eliminate the slick start?

 

[BobTurner]

Hopefully my spare mag will get him home. I would love any input from folks with one of the Slick Start mags.

1). Are they problematic or a good product.

2). Will I need to call my banker to have the old one overhauled?

3). Should we overhaul one of my spare impulse mags and eliminate the slick start?

1. I have the recommended Slick retard mag, and the Slick start electronic module. So far my engine has always (no sub-freezing no preheat experience) started easily, cold or hot. So I have a positive opinion. Note, if your battery is absolutely dead, you cannot hand prop this engine. The Slick start needs some power.
2. Overhaul price on the retard mag seems to be between plain mag and impulse mag price. Slick start module should never need maintenance.
3. As I previously noted I would not recommend anything other than short term emergency use of an impulse mag here. Having bits and pieces of the impulse mechanism falling into the accessory case is not a good thing.

 

[Mconner7]

Slick mag AD?

1. I have the recommended Slick retard mag, and the Slick start electronic module. So far my engine has always (no sub-freezing no preheat experience) started easily, cold or hot. So I have a positive opinion. Note, if your battery is absolutely dead, you cannot hand prop this engine. The Slick start needs some power.
2. Overhaul price on the retard mag seems to be between plain mag and impulse mag price. Slick start module should never need maintenance.
3. As I previously noted I would not recommend anything other than short term emergency use of an impulse mag here. Having bits and pieces of the impulse mechanism falling into the accessory case is not a good thing.

Bob, this was a new mag that went on my 540 10 years ago when it was first overhauled. Both mags were retarded impulse mags and I pulled them at 500 hours and replaced one with a SureFly SIM and the other with an overhauled impulse mag of the same model. That was about 300 hours ago with no issues. I looked around but don’t see any AD against slicks and 540’s. Can you reference the AD?
Thanks, Mark.

 

[BobTurner]

AD-99-04-04.
Repetitive 250 hr inspections required.

 

[Mconner7]

Slick AD

AD-99-04-04.
Repetitive 250 hr inspections required.

Ok I see why it wasn’t an issue on my motor, it’s an O-540 A4B5 out of a 1963 Aztec.

I will check with my friend on what model IO-540 he has.

 

[AZSteve053]

Per Lyc Lyc SI-1443S = The only approved Slick Mag is 6351 which IS Impulse

Download Lyc SI-1443S and lookup O-540-A4B5. That said, a lot of people have reported simple failures to catastrophic failures with Impulse coupled Mag's on the O & IO-540 series of engines due to harmonics over time. You MAY wish to discuss this with a Lycoming Tech Rep & a Champion Slick Tech Rep at some point. A lot of people utilize the 6393 Mag's which have a Retard breaker assembly to give you safe starting (no kick back) combined with a SlickStart module (acts like a "Shower of Sparks" system but newer, lighter & solid state). Make your own decision, but I would recommend making it based on the Engine & Ignition manufactures 1st hand input.

 

[Mconner7]

Thanks for the input Steve, I will talk to someone at Slick.

 

[Traash]

I have both a 6393 and a Slick start available for sale.
350hrs on both, working with no problems when removed.
$750.
PM if interested.