BlackRV7

BlackRV7

Well Known Member
I had slick mags on my prior engine but have switched to Bendix on my new Barrett Precision engine. On the slicks there were two attachment points on the back of the mags, one for the p-lead (also where I hooked my tach line up from my Dynon EMS) and a ground. On these Bendix (S4LN-21 non impulse for example) where am I to hook up the lead and ground? I have done a couple
Google searches and can't find a diagram.

HELP:eek:;)

Time to start this thing up!!
 
It's internal...

BlackRV7 said:
I had slick mags on my prior engine but have switched to Bendix on my new Barrett Precision engine. On the slicks there were two attachment points on the back of the mags, one for the p-lead (also where I hooked my tach line up from my Dynon EMS) and a ground. On these Bendix (S4LN-21 non impulse for example) where am I to hook up the lead and ground? I have done a couple
Google searches and can't find a diagram.

HELP:eek:;)

Time to start this thing up!!
Click to expand...

Dana... thank the Aeronca folks -- it's an internal connection....

http://www.aeronca.com/manuals/BendixScintilla/User_operating_instructions/BS-S4RN2X-083.jpg

Full service manual here....

http://www.aeronca.com/manuals/BendixScintilla/index.asp

Google wins again....:D

PS

The Google search was "S4LN-21" in "Images"
 
Last edited:
Just a quick note as I've recently gone through re-terminating my Bendix P-leads...

(By the way, if you want to see a much clearer picture, check out the Aircraft Spruce catalog, the ground terminal kits are shown on page 260 of the 07/08 catalog.)

If your P-leads are made from MIL-C-27500 shielded wire you will likely find the individual strands of shielding are too flimsy to allow proper termination within the nut-and-ferrule arrangement. I did a fantastic job of terminating mine two years ago, but last weekend I found the shield termination had frayed and only a few of the fine shield strands were left intact as a result of engine vibration. In truth, the nut-and-ferrule shield termination was really intended for much heavier braided shield, not the fine shield of MIL-C-27500.

If your P-leads are MIL-C-27500 wire I would suggest that you terminate the shield properly with a 22awg wire, crimp a lug onto the grounding wire and then attach the lug to one of the four screws that holds the breaker cover in place. This is what I ended up doing and it works fine. BUT you also have to insert a spring between the end of the insulating sleeve and the ground wire connect washer in order to ensure the washer, with your ground wire soldered into it, is constantly being pushed up against the breaker contact. I used half of the return spring from a ballpoint pen on each P-lead and it seems to be working out very well.

The alternative is to purchase magneto filter capacitors and install them. The ones supplied by Spruce have beastly heavy shield on them and will no doubt work perfectly in the nut-and-ferrule grounding termination.
 
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