P-Mag Cotter Pin

Hey - quick question. I recently pulled off my P-Mags as part of my condition inspection, and one of them had the smaller 3/32" cotter pin installed.

I ordered the recommend Slick cotter pin from ACSpruce.... and had a bear of a time getting them installed.

1. When the cotter pins are installed, you are only able to bend over one leg. The second leg just barely makes it out of the P-Mag shaft and into one of the gaps in the castle nut. Is this correct? It just seems weird to be able to bend just one of the two legs.

2. With the limited clearance in the engine, it seems to make more sense to bend the pin leg sideways, and tuck the end into one of the castle nut openings, rather then bend it over the top. Any reason not to bend the pin sideways, rather than over the top?

Thanks,
Jason

EDIT: The original post below is related to the SLICK recommendations for installing a mag drive gear cotter pin. The official documentation from EmagAir for the PMag states this:
Service Notes:
Operating Notes: Cotter Pin Inspection/Size: We recently increased the size of the cotter pin that secures the drive gear castle nut to the ignition shaft. New pins are 5/64″, and as a reminder, the ends of the pins need to be secure to help prevent movement. Earlier pins have been in service for years, but we’ve have occasional reports of pins coming loose and/or breaking. So we recommend replacing pins at your earliest convenience, but not later than your next annual inspection.

The current manual drive gear installation section:
"4. Install the drive gear on the E-MAG shaft using the woodruff
key, washer(s), castle nut, and 5/64” cotter pin provided.
Two washers are included – use one or both as needed.
Torque to 120-150 in/lbs. Make certain the cotter pin ends
are secure and lay flat. The back wall
of the accessory case will be close to
the end of the shaft."

Everything I can find related to this cotter pin states that it should be installed with one leg bent over the end of the shaft and the short end bent down next to the side of the nut.

It seems the official cotter pin is modified to shorten one leg to minimize the work needed to install it. It seems to be too short to bend down beside the nut.

I even looked at some of the other ignitions out there that use the same gear and the ones I found had the same advice...bend it over the end of the shaft.

The official SLICK marketing pictures also show the pin bent over the end of the shaft.

If someone wanted to, they could measure the clearance between the end of the shaft and the back of the engine using some clay or something similar.

First, the slick replacement pin is not the one to be used in a Pmag. As noted below, one leg is too short. The pins used by emag air are much longer, with the xtra length used to assist in pulling the pin through the shaft hole, and allowing the legs to be subsequently trimmed, removing the part damaged by your needle nose pliers but leaving enough length to bend the legs properly.

Second, per Brad at emag air it is recommended that the pins be installed so both legs are bent around the castle nut and tucked into the gaps. For clearance reasons, do not bend one leg over the top of the shaft.

Erich

You don't happen to know the part number of the cotter pin that Emag Air recommends?

Brad is in your neck of the woods. Call him.
Why go with second hand information?

erich weaver said:

Second, per Brad at emag air it is recommended that the pins be installed so both legs are bent around the castle nut and tucked into the gaps. For clearance reasons, do not bend one leg over the top of the shaft. Erich

Click to expand...

Correct - both legs are bent around the castle nut.

For the correct pin, I used an on hand 5/64" pin and trimmed the legs as needed. Remember to file the pin ends a little to make it easier to install. Even so it is hard.

Carl

When you remove your P-mags, inspect the shaft for play and smoothness.

If the shaft is difficult to turn (crunchy), return it for repair.

If the shaft can wiggle side-to-side, return it for repair.