RV-14 Build

The last few evenings I’ve been working on finalizing the wiring runs in the engine compartment. I looked at a few other aircraft blogs to get a few ideas, and ordered a few supplies. I started by working on the ignition leads and the EGT and CHT probe wiring. I switched out some of the adel clamps I had been using and went with -6 size clamps for all the ignition leads. The leads are slightly loose in this size clamp, but the -5 size is too tight. I wanted to be able to run zip ties through some of the clamps, and it’s helpful to have a little bit of play. The silicone cover on the leads sticks very well to the cushion clamps, so the -6 size seems to work well.

I also used some short (1/4 inch) lengths of rubber tube to create stand-off spacers for the wiring. Running zip ties around the wire bundles and through the tube keeps the wiring together but separated by 1/4 or 1/2 inch or so. Apparently it’s a good idea to have some spacing between the ignition wires and the other wiring runs to minimize interference.

Installing adel clamps is a pain, even with the clamping tool and using safety wire to hold the clamps shut. It’s just slow going.

It’s also slow going trying to visualize the wiring runs, and trying to figure out what wiring will go where. I had to redo work a couple of times, and can already tell I’ll be redoing things in the future. It feels like an iterative process to get everything worked out and squared away.

I’m using a fireproof abrasion protection sleeve on almost all of the wiring. This helps keep the wiring neat and tidy and I hope it will keep it cleaner. The sleeve can be slipped on around the wiring which makes it much easier to install and remove.

Tonight I tackled a few small jobs that had been on the to-do list. I switched out the manifold pressure fluid fitting for one with a restrictor inside, I took some adel clamps off and reinstalled for better wire routing, I safety wired the oil dipstick mount, and I plugged the e-mag ignition cables into the spark plugs.

The manifold pressure fitting I had installed was the Vans component I had originally installed. I later bought the Aircraft Specialty emag install kit, which comes with a 45 degree fitting with a flow restrictor inside. The flow restrictor dampens the fluctuations of air pressure when the engine is running, making for a more accurate manifold pressure reading.

To replace the fitting I first took off the air line, and tried to access the fitting. The baffling makes access a little difficult, so I decided to disconnect the oil return line so I could move that out of the way to gain access. I was then able to access the fitting and remove it. I cleaned up the threads, and then installed the new 45 degree fitting (used loctite 567). Unfortunately I could rotate the 45 degree fitting due to interference with the fluid fitting for the oil return line. I ended up removing that fitting too, installing the MP fitting, cleaning the threads, and then reinstalling the oil return fitting and then the line itself. It was a bit more work than I hoped, but it turned out well and the new setup is much better. The 45 degree fitting also allowed me to reroute the MP line to a more convenient location, out of the way of the oil cooler scat hose.

Safety wiring the oil dipstick mount was hard to reach, but not too bad once I had figured out how to get my hands into the small gap.

I plugged in the ignition lines, and started working on changes to the clamp setup to hold the lines.