Fuel valve, electrical tray, subpanel

Another busy day at the hangar.

Fuel valve

The stock fuel valve is a pretty weak operating/looking unit. It does not have a firm or positive operation, and without labels you cannot tell if the thing is on or off. For something like the fuel system, I will pay a premium to have quality components. So, I had to take off the old one (more negative progress). It's pretty straightforward to loosen the fuel lines, but to get the thing out it's a pain because of the location - it sits sort of between the seat pans and in front of the spar, so it's hard to access from outside the plane. 

No pictures of the new valve yet, but I'm going to order it soon and here's a link to the product. Much more impressive - can't wait to get it.

Electrical tray

Looking at other blogs and a local friends, it seemed like a good idea to put the electrical fuses on a drop down panel. I fabricated a drop down tray that attaches from the subpanel to the instrument panel. Of course, nothing is simple and there is  a section of the subpanel that has some overlap. To compensate, I added a small trim piece so it would sit flush. 

You can also see I had to drill out a rivet on the subpanel sections. It was bent over, and sure enough the hole was rounded out. I started looking around and noticed the subpanel was in pretty sorry shape. It had all sorts of holes in it and crappy edges. Here is what I'm talking about:

Anyway, it was clear this was not up to my standards and I was going to rebuild this section with new parts. I'll order them with my new fuel valve. Since this whole structure was coming out, might as well only temporarily fit up the drop down panel. It will be riveted when the new subpanel is installed.

Here it is temporarily installed

Bendix fuel injection servo pain

So I've tried a bunch of combinations for fitting the mechanical and cable linkage to the fuel servo. The good news is that in these separate configurations, the cowling will fit. The bad news is, the control cable does not have enough force to operate the mixture arm through the full travel.

This is pretty frustrating. Van's can't figure every combination of equipment, but you would think that a vertical induction fuel injector servo - which is pretty similar in size to the standard carburetors - would fit. The thing that troubles me is how much the cowl is off center; the passenger side has a 2 inch gap and the pilot side has less than 1/8"...WTF!

Well, the news got worse. I took the servo off to see about just remaking the ram air filter box, when I saw this:

The little white dots you see are corrosion (or "rust") on the inside of the throttle body. To give some perspective here, they are like someone took an ice pick and went to town, or maybe a really small drill bit randomly scattered on the inside of the throttle body. This was the first time I had this apart, because when I purchased the project it was already mounted to the engine. This particular part came off of a twin engine Piper Comanche and was rebuilt/refurbished just before it was installed. So, naturally I was wondering why the hell it would have been corroded. At first I couldn't tell if it was mechanical damage or corrosion, eventually discovered it was corrosion. But, a bit of good news... the shop that rebuilt it confirmed that the corrosion damage was there BEFORE it was sent it. His best guess is someone discharged a dry fire extinguisher into the throttle body and the corrosive stuff that puts out the fire pitted the inside. Also, it won't get worse or mess with the operation of the unit! Not bad, considering I was about to start shopping for a new servo - about $2000. Part of me wanted to get a new one that had the proper linkage orientations, but this is a much more affordable alternative.

So, the servo is OK but I need to figure out how to get the mixture linkage to work.