Little by little. That's the name of the game these days. I've spent the last few weeks working on cars, so not much time left for the plane. This past week I chipped away at the lower cowl fit. It's a bit tougher to deal with by myself than the top cowl has been - gravity always seems to win and makes getting it set into place hard. It's a lot bigger than it looks in pictures! I got it set against the fuselage and used the same method for trimming as I did the top. I drew a line 2" aft of the firewall and then transferred that to the cowl.
The instructions say to just do the bottom portion for starters, but stop before going up the sides. The idea is to make it match up with the bottom firewall first so you can then always get it into a predictable position before cutting the sides. I trimmed the bottom, but was definitely conservative. I'm going to have to do the off and on thing a hundred times to get it right, just like the top. Given how hard that is, I'll probably wait until I have some help.
Shifting gears - I finally received a couple of things I've been waiting on for a long time - the extension kit for the backup alternator and the firewall penetration steel grommets for the throttle/mixture cables. I bought the grommets because the routing I decided to use for the cables makes them take a big turn through the firewall and the grommets help support them (the grommets are basically a split steel ball that clamps around the cable and can hold them in position). I pulled the forward top skin off the fuselage so I could get at the aft side of the firewall for drilling. This would have been nice to do eons ago before the engine was even on, but not knowing where everything would end up going, I didn't want to drill a bunch of holes in the wrong places.
You can see the holes I started below the top firewall stiffener. I am putting the passthroughs in the angled portion of the inset of the firewall. Drilling through thin stainless steel is always loads of fun! I got the screw holes drilled, but my unibit isn't large enough for the center hole. Guess I need another tool!
This is what I have to show for the next 6 hours of work. Not much! Figuring out the exact cable routing took a lot of head scratching. The cables I got are beautifully made (McFarlane), but as is the norm these days, they won't fit without making some modifications. The routing for the mixture is going to take it right into the vertical exhaust support. I decided the best plan of attack was to swap the exhaust support to the other side of the cable bracket (the big, gold bracket). I moved it from the inside to the outside. In doing so, I had to make a longer steel tube and a longer rubber hose because now the support has to attach to a different sump bolt. It's not ideal, because it changes the angle of the support so it's less vertical than it was before, but there's not much else I can do. I think it should still keep the exhaust from moving vertically.
The cable bracket has to be modified a little, so I pulled it and the throttle body off and did some surgery on it. I'm sure after another 6 hours I'll have a single bolt in.
I thought I was going to get the alternator put in, but surprise surprise, I ran into an issue with the studs. I had been told I could use normal 1/4-20 bolts cut off to make studs, so I bought some and went that route. Nope. They thread in with finger pressure alone. Not exactly what they should be doing! It turns out the standard Lycoming studs are indeed 1/4-20, but the threads on the end that go into the case are a slightly different shape, even though the pitch and diameter are the same. That slight difference makes them fit much, much tighter. So in the end, I really need the Lycoming studs to get a good fit. Back to the waiting game!
