Timing the Mags

With finally having all of the right tools in place, I was able to time the mags this afternoon. I started with the right. When I got to the left, I found that I didn’t really have enough adjustment. I could get the light on the timing box to change only when I was right at the edge of the adjustment, and only when I applied a little bit of force beyond there. I called Bob for advice, and he said that the gear on the front of the mag is designed to be installed in one of two ways, just for this purpose. Here’s what it looks like.

Left Mag and Impulse Coupling

Left Mag and Impulse Coupling


While this picture is blurry, you can see that it is the left mag because it has the impulse coupling, there between the gear and the mag. Note how the gear has a slot in the back where it mounts to the impulse coupling. Now check out the next two pictures.
Slot aligned with slot

Slot aligned with slot


Slot aligned with tooth

Slot aligned with tooth


Notice that on the first picture, the slot on the back of the gear is aligned with a slot between gear teeth. In the second picture, the slot is aligned with a tooth. Since there are 13 teeth and 13 is an odd number, it works out that the gear is not symmetrical. I removed the cotter pin and castle nut, then removed the gear. I reinstalled it 180 degrees different in rotation, torqued the nut, and reinstalled a new cotter pin. Upon reinstalling the mag, I found that the timing light changed right in the middle of the adjustment range. I finished timing the left mag, and both are set right to 25 degrees btdc. With that work right next to the mags done, I installed the battery. This allowed me to test the wingtip lights, which I had been waiting to do before I installed the tips. I didn’t want to have to take the tips back off if the lights weren’t working! I mounted the lights onto the tips, and then installed the tips. Tabitha came out for a few minutes and we verified the calibration of the oil temperature sensor and the CHT sensors by dipping them into ice water and near-boiling water. In the case of the oil temp sensor we had to dip the sensor for a while, then wipe it off and stick it back in the hole so that it would ground in the right spot. All of the sensors were very close, certainly as close as they need to be. While she was there to keep an eye on things, I cranked the engine over with the spark plugs removed to prime the oil system. After about 45 seconds the oil pressure was up to 60 psi. I reinstalled the top spark plugs and torqued all of the plugs to 35 foot pounds. Then I spent a few minutes going through the menus on the Dynon units setting up the limits, color ranges, and other things like that.