Firewall Forward

November 12, 2012

More Parts on the Firewall, Engine Prep - 9.0 Hours

Well, we're well into November now. The elections are over, and it's been very worrisome about the future of our country. I only hope that when I finally get this project finished, I'll still have the freedom to fly it. And fuel available. All I can do is pray for the best and continue to go forward.

There hasn't been a huge amount of visible progress around here lately, but I have been busy. Busy in a pretty steep learning curve. It seems I'm spending more time reading and studying than ever, as I climb the knowledge curve about firewall forward stuff. And learning about this engine. You'll see what I mean as I detail my efforts.

First, a good friend of mine down in Ramona, California, Bruce Hill, tipped me off about a very good modification to the nose wheel strut that he learned about. He's building a very nice 9A and he's very sharp! I really respect him and his excellent work. It's a simple concept. It replaces the AN5-20A bolt that holds the strut in the socket with a tapered pin. It seems that a lot of RV's have experienced wearing of the bolt in the hole from the movement of the strut during landings and takeoffs, and the strut eventually becomes loose. This tapered pin is a press fit, and no movement can occur. It's inexpensive and makes sense, so after learning all about it I decided to go ahead. I'd rather do it now than later, because if you do it later you have to take the engine mount off of the plane! The only fly in the ointment is the price of the tapered reamer that's required for the job. It's expensive and you only use it once. I hate buying one-use tools. But Bruce was kind enough to loan me his and he sent it to me! If you'd like to read the article that convinced me, click on this link ---> RV Nose Gear Strut Tapered Pin

Here's a picture of the article I printed out, with the tapered reamer that Bruce loaned me. I'll be taking care of this little job before hanging the engine. I ordered the tapered pin and associated hardware, too. It all came to around $23. Pretty cheap for such a good upgrade!

Next, I've spent some time looking over the list of items in the Firewall Forward kit that Vans offers, along with the plans and directions, such as they are, to decide which parts to purchase next so I can keep busy and continue moving forward toward getting the engine hung. The list in the catalog shows a number of bags of hardware, but you don't know what's inside most of them. Some of them are quite pricey. So rather than just blindly order them, I called Vans and they were kind enough to email me a list of the contents of the hardware bags. I'm glad they did! I got online and priced out individual items and made a somewhat startling discovery. Some of the hardware bags cost more than the sum of their contents! Quite a bit in a couple of cases. In only one case was the opposite true. I don't need some of these items, so I wanted to pick and choose. I don't need bags of more rivets, for example. And the engine I bought has some of the hardware already on it. Anyway, if money is an issue and you'd like the list of hardware bag contents, let me know and I'll email it to you. Or call Vans and ask for it. Anyway, I put together another short list of things I wanted and could use right away, and drove over to Vans to pick them up. Then, over the last couple of weeks, I've been making some slow visible progress, mixed in with a lot of reading.

It's not obvious at first glance, but here are some subtle changes that I have accomplished recently. The two red arrows at the top point to some one-lug platenuts that I installed. These two will hold the oil pressure sensor hose in place with some clamps that I also bought. Next, the red arrow on the right down below points to a third platenut that I installed. This one will hold a clamp for the breather tube and probably the ground cable from the engine as well. Finally, my new steel fitting came in for the fuel hose fitting, and you can see it on the left near the solenoids.

Next, I also bought the 90° elbow that goes in the bottom fitting of the Transducer Manifold seen below. I also bought some #2 Permatex, which is used to lubricate the threads on all these fittings and seal the connection. Here's the assembly, finally bolted to the firewall. I may have to take it off once more, to either install a fitting in the top spot for manifold pressure, or cut this part of the thing off if I don't use it. We'll see.

I've also been turning a lot of my attention to my engine. It's been sitting here untouched, but it's high time I learn a thing or two and get it ready to install. I have been reading a lot online, as well as two good books I bought recently. I have the classic Tony Bingelis books "Engines" and "Firewall Forward". They come highly recommended by Vans, and I was able to find good deals for used ones online. So I'm well into the task of getting myself educated. Not a lot to show for it yet, but I know this is time very well spent.

Here's an example of some of the things I have learned very recently. Here's a picture of the accessory case on the rear of my engine, as it came from the guy I bought it from. The first obvious thing is that the left mag is missing. He explained that it wasn't working properly when I was negotiating for the purchase, and I wanted at least one e-mag or p-mag anyway, so he took it off for me and covered the opening to keep moisture out. Now, thanks to the studying I have been doing, I can point out to you what all the cover plates, elbows, fittings, and other "stuff" is in this picture. Other than the mags, I didn't have a clue before now. So I know which gizmo is the breather tube fitting, the engine-driven fuel pump and all it's fittings, the oil cooler output and input fittings, the tachometer fitting, and the cover plates for the vacuum pump (which I won't be using) and the prop governor (which I also won't need).

The funniest thing I've done, and it really shows just how unknowledgeable I am, has to do with the oil filter pad. Seen above covered with aluminum tape, I looked into this and started reading about oil filters and so on. I sent an email to a few friends, asking their opinions on whether or not I should invest in one of those 90° oil filter adapters, what size spacer I might need, etc. They all agreed that it wasn't necessary, and one even said it's one more failure point to avoid. I really breathed a sigh of relief, because the darn things are expensive! I'll be hanging the oil filter straight off the back on this engine. Okay... so I've been looking at this and asking myself "how do I fasten the oil filter to this accessory case? Isn't it supposed to spin on? What are all these holes for?" I see the black gasket underneath the silver tape, and I knew I'd need a new gasket. But I didn't get it. It never occurred to me that just because I don't need an expensive 90° adapter, I still need an adapter of some kind! Well, duh! Having never owned an aircraft before, my ignorance is really showing. And I'm a guy, mind you, that has worked on cars my entire life.

This is what good friends are for! I will have a lot of experienced eyes looking at my work as I go forward from this point. So I didn't get much work done on the airplane lately, but after some diligent studying and reading last night, I can now tell you not only about the straight-thru adapter that I need, but also how the oil flows through the engine, oil cooler and so on, and this neat thing called a Vernatherm that Lycoming invented to act as a thermostat for the oil, controlling the flow to the oil cooler. Neat stuff! I still don't know where to get the adapter I'll need or how much they cost, but at least I know what needs to be done. I want to get it taken care of before I hang the engine.

Next, I bought a 45° restrictor fitting at Vans that goes on the engine right above the right mag. A hose connects here that goes to your Transducer Manifold and the sensor for the oil pressure. In this picture, you can see that my engine came with a fitting already in place with a red cap on it. But it's not the right fitting. It took some effort, but I finally got it off and replaced it with the new one. Newer Lycoming engines like mine have two ports here to choose from, as you can see, there's a plug in the other one to the right. But I want this one. The other one can't be reached after the engine is installed, from what I read. So if the fitting ever leaks or needs replacement, you have to pull the engine to get to it. Not so good! I'll use the one on the left, thank you.

Here's the new fitting, in place. You use some #2 Permatex on the threads.

I temporarily hooked up the hose to it, so I could adjust the 45° angle to the right position so the hose doesn't rub on the mag. If you just follow Vans directions, they tell you to point it downward at a 45° angle. But if you do, the hose will hit the mag.

You can also see in the pictures above and below, that I tackled the base for the oil filter. I removed the silver tape, scraped off the old gasket, and cleaned it up thoroughly. I also unscrewed one bolt that was left from before, figuring any adapter I get will come with new hardware. It's now sealed up nicely again with blue tape, clean and ready for a new adapter and oil filter. I really want to get those on before I hang the engine. Once I get this taken care of, the engine is ready to go! I can put the e-mag or p-mag on after the engine is installed. So I won't worry about that for now.

Next, back to the firewall. I've been wondering when I should rivet the firewall recess in place. There aren't any clear directions anywhere, that I can find. I decided that one way to know if it's a good time or not is to at least cleco it in place. As I continue to work on things, if it's in the way I'll know soon enough. If it's not in the way and I get ready to hang the engine, it's good to go and I'll rivet it on.

Finally, as you can see, I temporarily bolted the engine mount back on. I've been planning on finishing up the main gear legs to get them ready for installation, and wondering how I'm going to lift the fuselage up enough so I can slide them in. I have something in mind that involves using the engine mount. We'll see if it works out okay. Stay tuned!

A sharp-eyed observer might notice something missing on my firewall. Where are the penetration points for the throttle and mixture cables? This is something I've also given a lot of thought. Here's the problem. My situation departs from Van's scenarios because I will have an IO fuel-injected engine with vertical induction. The firewall forward drawings and plans from Vans assume that if you have vertical induction you will have a carburator, and if you have injection you will have horizontal induction. They do say that you can use the carburator drawings to figure out where to run your cables, but I found at least one builders site where it wasn't that easy. Fortunately, he was smart and he waited, too. He was able to drill the penetration points after hanging the engine. I don't think it will be a big problem to do that, once things are in place and I can figure out where I need the cables to be situated. So I'll wait for now.

There will be other things I'll be doing after the engine is in place that I thought I'd want to get done first, too, such as the lower hinges for the bottom cowl. As it turns out, I studied it again and it won't be hard to rivet them on with the engine mount in place. But those rivets all across the center, I'm glad they're in place now!

So that's what I've been up to lately. It seems I've been bouncing around between the gear, the firewall, and the engine. But it will all come together here before long.

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