Ignition wiring
I wasn’t feeling well today. Don’t know if it was a bug or simply being over-tired. I had reserved a plane for 1pm to practice some landings and maneuvers. The weather was absolutely perfect, but I just didn’t feel up to it. I spent time with the family and messing around on the plane instead.
I finally came to terms with the control cable quandry. I read through the entire section in the Spruce catelog and didn’t find any information that would have prevented me from mis-ordering. I did find one helpful thing, an optional polyolefin covering for the cables. I’ll get that on the next ones.
I also decided to double (and maybe triple) check that the lengths were correct. I placed all of the various arms and adjustments to their mid-position. I mounted the panel and quadrant back in the plane and placed the levers to their mid positions. While I held the cable roughly where I wanted it to be routed, Julie measured the difference between the end of the cable and the mounting hole in the quadrant lever. Adding on 7/8″ for the clevis end, I then calculated the correct length for each cable: mixture 51″, prop 48″, throttle 50″. There’s a fair amount of adjustability at each end and in the routing, so +/- 1″ would even work OK.
The mixture cable especially has a lot of flexibility since the arm angle can be changed to any position and the end on the lever arm can be adjusted. I put everything at its mid-position and mounted the mixture arm so the lever arm doesn’t hit the bracket. Hard to describe, but you’ll understand when you get here.
I got some great responses from the Yahoo Lycoming group. The standard mag wiring is right mag to upper-right and lower-left spark plugs, left mag to upper-left and lower-right spark plugs. This is to balance out the RPM drop when doing a magneto test. Dan also suggested just wiring one side to all upper and the other to all lower just to make troubleshooting easier, which was a good idea. In the end, I decided to go with the standard wiring. EmagAir provides all the parts, a crimper, and great instructions for making the ignition harness. I put on 6 of the 8 coil ends onto the wires. It’s time consuming work, but I’m going very carefully.
I also ran down to the hardware store and picked up a couple parts for a poor-man’s prop torque extension. I wish I could claim that I thought of this, but I got it off the VAF forum. Buy a bolt and nut (and washer for good measure) that are the same size as the prop nut. In my case this was 3/4″
With my 3/4″ wrench on the prop nut, I put the bolt/nut “adapter” in the other end and then attached the torque wrench to it. I used the formula that came with the torque wrench to de-rate the torque value appropriately for the extension. Unfortunately, my good torque wrench doesn’t go high enough for the prop bolts. I’ll have to borrow one.
