Magneto gasket required

Everyone probably knew this out there but me; but just wanted to pass along my experience just the same in hopes of saving someone else some downtime and $. I was retiming my left magneto on my RV-3A (O-290G) and I didn't realize the gasket under the outer adjusting "slot" had torn away. After "stabbing" the mag and adjusting it I put on the nuts and went to torque it to spec and I heard a breaking sound, almost like china cracking. After backing off the nut I realized the outer part of the magneto had cracked, but it wasn't until I pulled it to take it in and have it swapped out for another serviceable body that I realized the gasket was gone. $155 mistake that I won't let happen again.

Doug Lomheim
RV-3A
4.2 hrs now (for me)

https://www.dropbox.com/s/sg3n95mp5rxtz3k/Magneto ear broke.jpg

You more than likely had the magneto cocked in the engine, this had nothing to do with the gasket. Its an easy mistake to make if you're not careful when you install the mag.