Air Vents and EGT wiring

Time: 5 hours

I purchase a pair of 2″ AIrKit anodized aluminum vents from Aircraft Spruce. These things aren’t cheap, they’re around $160 each, but seem to be well made and are a good size for what I need to do. I also have AitKit cabin lights so everything kind of looks similar. I made up some fillers out of anodized aluminum (for the front) ¬†and fiber glass sheet (for the back) with a 3 1/8″ hole saw. I then cut a 2″ hole in the middle using another hole saw. The cuts came out well enough. I had to modify the fiber glass ring a bit to get it to sit a bit flatter. The thread on the vents seemed to be long enough, but it was a pain getting the back to screw on. I epoxied the fiber glass ring to the rear of the dash and the front is just held in place by the pressure of the backing nut. I’m happy with the way these came out. They look a lot nicer then the plastic vents and they will seal off much better as well.

I also finally was able to finish up the wiring of the 2 EGT sensors. I had order some K Type ¬†thermo coupler wire which appeared to be exactly what I needed at a reasonable price, but after running the wire and starting to wire it up I found that they had sent the incorrect wire (knew it was too good to be true). They said they will send the correct wire, but it’s back ordered (of course) and they weren’t sure when it would ship out. I decided to go back to my original place called Omega to purchase the wire. Their wire is really high quality but it’s pretty expensive. I purchase 25ft of armored K-Type thermo coupler wire for around $80. It arrived a few days ago and wow, it’s nice stuff. The wire I used (GG-K-20S-SB-25) is a 20 gauge glass insulated 2 core wire with an other glass insulator and then a stainless steel outer sheath. There are other sheathing you can get, but I wanted to use the braided stainless steel. The connection to the EGTs is made by 2 ring connectors, Unfortunately I could only find spade type connectors that are usable with the K-type wire. The spade connectors are made from Alumel and Chromel which is the same material as the K-type wire so the temperature characteristics will be the same. The yellow wire is Chromel so you use the Chromel spade connector on it and the red wire is Alumel so the Alumel connector is used on that. I used a standard open barrel crimper to crimp them on. Working with the K-type wire is a bit of a pain because the wire insulation is like a cloth material and doesn’t cut well with wire stripers. After the wires are bolted together a final length of heat shrink is put over it.

Lastly I roughed in the CEET tubing for the air vents. Because I’m using 2″ air vents I had to find a 3″ to 2″ reducer to tie into the NACA duct. I found some on Amazon for around $6 each and they look like they will work. The NACA duct is a little smaller than 3″ so hopefully it will seal up OK. I’m waiting on my hose brackets to be able to actually connect everything together. The one issue I ran into is that the bar that I’m going to install to hold the avionics shelf gets in the way of the tubing run.

Finer glass backing rung epoxied in.

Vent mounted in the 3 1/8″ anodized aluminum ring. It’s all just held in place with the pressure of the backing nut. The vent moves fairly easy so I don’t think it will be an issue with it coming loose. The fiberglass ring also creates some tension on the nut so it holds very tight and won’t spin loose at all.

EGT wire connection. I could only find spade connectors in Alumel and Chromel, but this all get wrapped in heat shrink so that will keep everything together and offer some strain relief.

Big piece of heat shrink covers up the join.

This 3″ to 2″ reducer looks like it will work. I may cut down the flange a bit to give more room. I need to use 3″ CEET to join it to the NACA duct and then 2″ out to the air vent.

Test fit of the CEET tubing for the air vents.The tight bend may cut down on air flow, but not much I can do about it. I don’t want to put the bar on the other side of the tubing because it may interfere with the fuel selector.

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EGT Sensors and Fuel Lines

Time: 1.5 hrs

The new EGT sensors came a few days ago and today I had some time to fit them. I think the new sensors will work better. These have a shorter lead so I purchased some K Type wire to extend them. they are also a bit easier to remove since the bolt holding them in is separate from the sensor body so you don’t have to turn the whole sensor (including the leads) to get it out. The only thing I don’t like as much is that the sensor has a 90 degree bend and so I can’t route the wire the same way I had routed it with the old sensor. I think they may work better on the front mounting holes, but from what I read the rear holes have a bit more accurate reading so I want to keep them in the back. I think the way I mounted them should work OK. I don’t want to take too much of the bend out of them in fear that I’ll break it.

NOTE: I thought I had a photo of the installed EGT, but I guess not. I’ll take one tomorrow and upload it.

The other thing that came were the fuel lines. Wow these are excellent quality fuel lines. Steve even used the blue fire sleeve that I wanted. They usually use the orange type of sleeve. I think all the lines will fit fine, the only ones still in question are the ones that screw to the fuel pumps since I don’t have those built up yet, but it seems like they will all work. I’ll come up with a more detailed install of the fuel lines when I actually do the install.

The new EGT sensors have an adapter that screws into the M8 thread and then the sensor bolt screws onto the adapter. I used some high temperature anti-seize (copper color) on the threads so that they don’t rust up and are hard to remove. I don’t know what the torquing on these should be so I just got them reasonably tight.

The new EGT has a much shorter lead so it will be easier to replace it if I have to. These are made by MicroFlight (Micro-1000)

The EGT has a 90 degree bend and I didn’t want to take the bend out. Think this will still work fine running the wire up between the cylinder heads.

A short of the fuel lines running between the firewall and the gascolator and fuel pump location. These will need to be torqued and secured.

All the fuel lines in and out of the FT-60 seem to work as well. I need to make a proper bracket for the FT-60.

A few photos of the -4AN line running from the tee (connected to the fuel regulator) into the fuel flow sensor. You can also see (in the upper photo) the short connector hose that feeds the tee from from the fuel regulator.

The -6AN return run has a special banjo fitting that Steve made. You can’t buy a stainless steel 10mm Banjo to -6AN fitting anywhere, you can get aluminum one, but not stainless steel. I’ll need to get a photo of it when I do the install of the fuel lines.