Over the last week I continued to chip away at the firewall fwd stuff. Most notably, the engine wiring. I absolutely hate looking at a car, airplane, whatever, that has a rats nest of wires running everywhere. Frankly, I don't like the way that Cessna or Beech run their EGT & CHT sensors either; They are just adel clamped along the bottom of the rocker covers with wires folded back on themselves and a bunch of wire ties holding it all together. Its pretty easy to work on, and it also goes together fast, but it just looks cobbled together.

I wanted to avoid that if I could, so I spent a while experimenting and determined that I could run all that stuff behind the intake and exhaust pipes and get a lot cleaner result. This makes the terminals a little harder to access but I don't think it's going to be overly so.

Anyway, that took a lot longer than if I had just slapped it together like a production plane, but it's sure going to make that engine pretty.

I then permanently installed the magnetos. There are a couple of positions you can rotate the mags to that make it impossible to get a torque wrench on the stud nuts, but I was able to find a clocking position for both that allowed me to get a torque wrench on all 4 stud nuts, either with a socket or a crowfoot. I torques them down to 17 '/lbs per the Lycoming torque chart

I also hooked up the magneto harnesses including the hose for manifold pressure that tells the Mags when to advance timing. The hose that comes with the Pmags is soft silicone rubber. TS flightlines makes a more robust solution, but this is one place where I didn't see the need to upgrade the oem solution.

I got some appropriate sized nylon tube from the hardware store (I believe it was 3/8" ice maker line) and a nylon Tee fitting. Then I slipped a 1" section over the silicone line anywhere I wanted to support it so that I could just zip tie it to the engine wire bundle without pinching it shut. Even so, I elected to not run it through the adel clamps that support the rest of the bundles because of the pinch concern. The two lines are tee'd behind the upper r/h engine mount and run from there to the hose barb coming off the main manifold pressure transducer mount. I also left enough extra length in the way I routed it that I can cut a couple of wire ties then have it loose enough to blow in it and time the mags without undue effort.

I also rethought how I had the engine grounded. I had two ground cables starting at the recommended IO390 ground point per the RV14 print. One on each side of the bolt through tech engine case. I reasoned that he chances of both of these going bad at same time were almost nil and that bolt certainly isn't going anywhere.

However, the P-mags need a local engine ground and after looking around for a while, I decided that a way to keep the wire run simple was just to ground them to one of the studs coming through the vacuum pad cover, which my main engine wire bundle runs right by.

Since I was in that area anyway, I elected to relocate one ground strap to that area as well. I now have a ground strap running from the engine case down by the dipstick hole to one of Vans suggested locations on the firewall, and a second ground strap running from a stud on the vacuum pad (shared by one of the Pmag grounds) to a brass bolt on the firewall that also terminates the negative battery lead. I can't get much more redundancy that his setup.

I don't remember if I already mentioned this, but I was going to do all my big wires with welding cable just because it's much easier to work with than mil-spec tefzel coated wire when you get that fat. Turns out the stuff I bought from B&C was 4AWG, not 2AWG. It would have no doubt been fine, but I had some Tefzel mil-spec 2AWG from Vans so I remade the main ship battery leads and big starter wire from that, then went to tractor supply and got about 3' of 2awg welding cable to make the engine ground straps out of.

At this point, all the engine wiring is done except plug wires, & EGT probes. I also still need a solution for the engine breather and fuel pump drain, but it's really gratifying to see this all start to come together.