P leads mystery
Posted: Fri Apr 25, 2025 4:42 pm
I have this solved, I think, but thought you might find this interesting. My mechanic and I have been going crazy trying to solve an intermittent mag issue. I have Bendix S6LN-21 mags, 10-51365-39.
Turns out my aircraft probably started out with the Scintilla mags. The Scintilla mags got changed out at some time to the S6LN-21's. But they kept the old Scintilla P leads in place with the exception of removing a spring. So I am told. The insulator on the Scintilla P-leads is much longer. So it was pushing the contact spring in the new mag down so far that it was at times contacting the points and grounding out regardless of the ignition switch being on both. AND there was a broken 1/2 of a contact bouncing around the points. Who knows what havoc it was or could of created. I assume it broke off due to the high stress of being pushed down so far. And when it was replaced they didn't find the broken half and just forgot about it!
I have new P-leads coming from Bogert. I can't believe those P leads are probably 75 years old. Time for new ones.
Turns out my aircraft probably started out with the Scintilla mags. The Scintilla mags got changed out at some time to the S6LN-21's. But they kept the old Scintilla P leads in place with the exception of removing a spring. So I am told. The insulator on the Scintilla P-leads is much longer. So it was pushing the contact spring in the new mag down so far that it was at times contacting the points and grounding out regardless of the ignition switch being on both. AND there was a broken 1/2 of a contact bouncing around the points. Who knows what havoc it was or could of created. I assume it broke off due to the high stress of being pushed down so far. And when it was replaced they didn't find the broken half and just forgot about it!
I have new P-leads coming from Bogert. I can't believe those P leads are probably 75 years old. Time for new ones.