Part number for stud that holds magnetos

Rick RV-4 · #1 01-10-2007, 07:36 PM

Anyone know the part number (or type of stud) used to hold the right magneto onto the accessory case on an O-360 A1D?

Long story short, I am installing Pmags on my RV-4. The case mounted studs that are used to attach the left mag (which was an impulse mag) will be too long when I use them for the Pmag. The shorter ones on the right side are the correct length. So I plan on removing the two studs on the left side and either using two bolts or two new studs.

If anyone knows the part number for these, or what exact type of bolts would work, please let me know.

Thanks,

Rick

Mel · #2 01-10-2007, 07:47 PM

The Lycoming part number for the shorter stud (5/16-18 x 1-1/2 long) is 31C-12.
The longer one (5/16-18 x 2-3/8 long) is 31C-19.

Radomir · #3 01-10-2007, 07:48 PM

I believe it's p/n 31C12 -- 5/16"-18 x 1.5"

Rick RV-4 · #4 01-10-2007, 07:51 PM

Thanks a million guys!

JimWoo50 · #5 10-20-2016, 08:34 PM

What does the p-03 stand for? There are 3 listings for the 31C-12 all with different p numbers in the ACS catalog and I would like to order the correct part to facilitate the install of my 2nd p-mag to replace my impulse mag.

chrisbryanolsen · #6 10-20-2016, 10:11 PM

The -p indicates the oversize of the stud. The stud is set by tourqe so if the value is not reached before it bottoms or is to short an oversized stud should be used.

Larco · #7 10-20-2016, 10:32 PM

cad plated steel exhaust studs for lycoming engines - 31c12
http://www.aircraftspruce.com/catalo...lycexhstud.php
These high quality exhaust studs are produced from cad plated steel in 5/16 x 18 standard thread size and are a direct replacement for the Lycoming part number 31C12 stud. These studs DO NOT feature a safety wire hole (refer to p/n 08-06780 for safety wire hole feature).
31C-12-P03 LYCOMING STUD from Aircraft Spruce
http://www.aircraftspruce.com/catalo...s_07-03182.php
31C-12-P03 LYCOMING STUD Factory New Lycoming Studs. ... CAD PLATED STEEL EXHAUST STUDS FOR LYCOMING ENGINES - 31C12. $5.35 ...

Walt · #8 10-21-2016, 05:12 AM

Quote:

Originally Posted by Rick RV-4

Anyone know the part number (or type of stud) used to hold the right magneto onto the accessory case on an O-360 A1D?

Long story short, I am installing Pmags on my RV-4. The case mounted studs that are used to attach the left mag (which was an impulse mag) will be too long when I use them for the Pmag. The shorter ones on the right side are the correct length. So I plan on removing the two studs on the left side and either using two bolts or two new studs.

If anyone knows the part number for these, or what exact type of bolts would work, please let me know.

Thanks,

Rick

FYI: P-Mag carries them for those folks that need to change to the shorter studs.