Surefly Excessive Mag Drop Trouble Shooting Procedure

[MisfitSELF]

Back in the Spring (2022) I had a Surefly installed but have only been struggling with excessive mag drops since my annual last month.  I noticed that Surefly now (not sure how old this is) troubleshooting guide for this.  Link below:

This seems like it would do the trick, but I question that you'd just adjust the standard mag timing to get it meet the POH criteria for mag checks.  How would anything but setting your standard mag to 20deg or 25deg (depending on your engine) be acceptable or legal?  I don't mean to restart the whole 20 vs 25 deg TDC debate but this procedure from Surefly seems a like a head scratcher to me.  Anyone know if Lycoming blesses this process?  (I guess I'll message them and see and report back).

https://www.surefly.aero/_files/ugd/f0684a_b1912ac854234753a1e424fc07665db5.pdf

 

[N201MKTurbo]

It doesn't sound crazy. When I time mags I set one very carefully and make the other one match. That is what they are doing. It would be better if they would flash an LED so you could match it with the mag timer.

[MisfitSELF]

On 10/26/2022 at 6:28 AM, N201MKTurbo said:

It doesn't sound crazy. When I time mags I set one very carefully and make the other one match. That is what they are doing. It would be better if they would flash an LED so you could match it with the mag timer.

So how far from the engine spec of 20degree advance of TDC are you allowed to go in order to match the SureFly?

[N201MKTurbo]

4 minutes ago, MisfitSELF said:

So how far from the engine spec of 20degree advance of TDC are you allowed to go in order to match the SureFly?

Well, from their instructions +-1 degree.

[MisfitSELF]

13 hours ago, N201MKTurbo said:

Well, from their instructions +-1 degree.

Continue reading to step 30.  You're to keep adjusting by 1 degree increments until to you reach the POH limits.  Ironically, my A&P got to 25deg TDC on the right mag when the mag drops were within POH limits.

[N201MKTurbo]

9 minutes ago, MisfitSELF said:

Continue reading to step 30.  You're to keep adjusting by 1 degree increments until to you reach the POH limits.  Ironically, my A&P got to 25deg TDC on the right mag when the mag drops were within POH limits.

So, what is the SureFly doing at runup RPM? Is it 20 or 25 BTDC? Maybe you have the wrong Surefly.

[PT20J]

SureFly is timed to engine at TDC. Advance is set by DIP switches. Sounds like maybe it was mis-set for 25 deg.

Skip

[Ragsf15e]

Exactly what I was thinking.  Check where you’ve got the SF set.  It should have the proper dip switch settings for 20deg, but the light goes on at tdc.  It can be confusing.  During runup it will be on fixed timing, but at whatever you've set it up to do…

[MisfitSELF]

5 hours ago, PT20J said:

SureFly is timed to engine at TDC. Advance is set by DIP switches. Sounds like maybe it was mis-set for 25 deg.

Skip

Checked, double checked, triple checked.  It's not set to 25deg at least by the DIP switches or light codes.

 

Edited October 28, 2022 by MisfitSELF

[PT20J]

2 hours ago, MisfitSELF said:

Checked, double checked, triple checked.  It's not set to 25deg at least by the DIP switches or light codes.

 

Then, I would consider sending the mag out for service. I had a Slick mag with only about 200 hrs since new that was dropping about 250 rpm during a mag check. Timing checked twice and was correct. Drops less than 100 after I sent it to Aircraft Magneto Service for IRAN. 

Skip

[MisfitSELF]

On 10/28/2022 at 4:15 PM, PT20J said:

Then, I would consider sending the mag out for service. I had a Slick mag with only about 200 hrs since new that was dropping about 250 rpm during a mag check. Timing checked twice and was correct. Drops less than 100 after I sent it to Aircraft Magneto Service for IRAN. 

Skip

My right mag was just overhauled and tested as part of this ordeal.