Matt's RV-7 Project » Engine

Desiccant plugs

Matt — Sun, 10 May 2009 02:00:36 +0000

I put in a new set of desiccant plugs in the engine this weekend… after two years of service, the old ones were starting to lose their magic ability to dry out when I put them in the oven every few months.

Sniffle valve

Matt — Mon, 30 Jun 2008 01:42:20 +0000

Fuel-injected Lycoming engines can sometimes experience a phenomenon wherein excess fuel drips down the induction tubes and pools in the intake manifold after shutdown. This can be a problem, since it could cause a troublesome fire during the next start. To alleviate this, you install a simple little one-way check valve in the bottom of the intake, which lets the fuel drip out of the engine onto the ground. For whatever reason, this item is colloquially referred to as a sniffle valve.

Here's a bad picture of the one I bought from Airflow Performance for a few bucks – it's basically just a normal AN fitting that's been drilled out and had a ball bearing and retainer clip inserted. Reduced pressure inside the manifold causes the ball to be sucked up to close the valve when the engine is running, but it drops down and lets the fuel drip out when the engine is shut down.

I knew from previous reading that the sniffle valve is too close to the exhaust pipes on an IO-360 with horizontal induction, so I installed it in a 45-degree brass street elbow to clear the pipes. The exact orientation of the valve is said not to matter much, as long as the ball is free to drop when the airplane is at rest. I also attached a 1/4" hose barb to 1/4" AN flare adapter, similar to the one I used for the fuel pump drain line.

I ran another 1/4" aluminum line from the firewall up to the sniffle valve, using a length of 1/4" rubber fuel hose as a flexible coupling. The forward (engine) end of the aluminum tube is ever so slightly flared to give the clamps something to work with – using a real beading tool would have been best, but I can't afford one and this is not a critical application. The aft end of the drain tube is attached to the firewall flange with an adel clamp, just like its twin the fuel drain line.

One more of the million firewall forward tasks is complete… and with that, I'm off to try and make a dent in the beer and ice cream still left over from Saturday's party.

Installed new fuel pump

Matt — Mon, 30 Jun 2008 01:28:09 +0000

At last, a chance to work on the airplane! Following much finagling, I managed to get the new fuel pump installed on the engine. It's pretty tricky to keep the thing aligned correctly and get the bolts started, while making sure the pump actuator lever isn't hitting the side of the pushrod way up inside the engine that actually drives the thing.

Not really visible here is the new gasket I installed between the pump and the drive pad. I couldn't get a torque wrench on the bolts – actually I could barely get a hex wrench on them with the engine installed on the airplane – so I just torqued them by feel and installed safety wire. It only took me about five tries to get the safety wire installed properly in the narrow space available.

Since replacing the fuel pump seems like kind of a big deal, I decided to make an entry in the engine logbook. It says: 0.0 hours – Original fuel pump damaged during installation – Replaced fuel pump with new Lycoming LW-15473 in accordance with manufacturer's instructions.

With the fuel pump replacement finally finished, I was now back to where I was a month ago. The next step was to hook up all the hoses, but this time around I didn't want to use a steel fitting for the drain line and risk fracturing the pump again. I decided to use a brass fitting, but I couldn't find one that I could easily substitute for the previous one. Luckily, one of the things I learned when I owned an airplane with a car engine in it – besides the most important lesson, being for goodness sakes, don't ever buy an airplane with a car engine in it – was how to make aircraft and automotive plumbing play together. Here's some 3/16" I.D. automotive rubber fuel hose, a brass hose barb to pipe thread adapter, a brass 3/16" hose to 1/4" AN flare adapter, an AN818-4D flare nut, and some Oetiker stepless hose clamps:

Down at the bottom of the firewall, the rubber hose comes off the suspended plumbing contraption that carries the dumped fuel out the back of the cowling. I really like this method of adapting cheap rubber hose to AN plumbing. Of course, I wouldn't use it for anything other than a vent line, but it's easy to make and I think it looks more professional than the plastic ice maker hose the plans specify for this application. I already had the special tool needed to install Oetiker clamps, so no problem there.

The drain line attaches to the fuel pump via the hose barb fitting, and that's that. I also installed the other three fuel hoses (input, output, and pressure) and torqued all the fittings.

Mounted fuel servo

Matt — Sun, 02 Mar 2008 02:00:19 +0000

Mattituck sent me a new gasket to replace the wrong-sized one they'd originally sent me with the engine, so I was finally able to bolt the fuel injection servo to the engine. I put a thin coat of fuel lube on both sides of the gasket before installing it.

There aren't really any detailed instructions on how to mount this thing, other than a drawing in the plans that shows the correct orientation. In one of the bags of stuff that came with the engine I found some 5/16" nuts and star washers, so that's what I used to attach the fuel servo to the sump. Confusingly, the Lycoming overhaul manual calls out a torque value for 5/16" nuts that's noticeably higher than what AC43-13b says to use, but it's largely a point of academic interest – even using a crow's foot, there's no possible way to get a torque wrench onto at least two of the nuts, so I just wrenched them all by feel until they were good and tight.

Looking down the business end of the air intake, you can see the four airflow pickups (or whatever they're really called) in front of the closed throttle plate. The Bendix fuel injection system is a purely mechanical system, in which the amount of fuel metered to the cylinders varies with throttle position and the rate of air flow measured at the intake. It's a simple design that's been around since the 60's, and based on my experience flying other Bendix-equipped airplanes it all seems to work pretty well if it's properly set up and adjusted.

To keep unwanted junk from getting lodged in the intake throat, I covered it up with masking tape:

Bolting stuff to the engine

Matt — Sun, 17 Feb 2008 21:11:34 +0000

This is the Precision Airmotive RSA-5 fuel injection servo. I need to get this guy bolted onto the airplane, but it didn't come with any instructions – so I don't know, for example, if I need a gasket between the servo and the oil sump, or what. I sent an email to Mattituck.

Van's makes a pretty well-done little kit that contains a bellcrank for connecting the mixture cable to the fuel servo, and a series of little brackets for anchoring the control cables to the engine. I removed two of the case bolts and attached the bellcrank bracket to the oil sump, like so:

The mixture cable bracket attaches via another pair of case studs, underneath the #4 cylinder. These nuts all have lockwashers under them.

The throttle cable bracket bolts to a threaded boss on the bottom of the oil sump. I safety-wired the bolt heads:

Those coarse-thread bolts didn't come drilled, so I had to use my handy bolt-head-drilling jig to do it myself:

Here we go, two drilled-head, coarse-thread bolts:

I attached the engine-driven fuel pump's inlet fitting:

…and the outlet fitting, with restrictor fitting to feed the fuel pressure transducer:

Hung the engine

Matt — Sun, 10 Feb 2008 22:21:49 +0000

With the engine suspended from the hoist, we unbolted and removed the pallet, leaving the engine swinging:

Matthew Brandes and his foreign-exchange student Nat came up to help put the engine on. Matthew has already been through this exercise on his RV-9A, so he is an old hand. We maneuvered the engine into place and managed to get the first three bolts in without much trouble, but the last one was kind of a goat-rope.

Chad was there to help too. Maybe he'll get started on his own RV soon…?

Finally, all four bolts went in. We unhooked the hoist and lowered the tail down before final-tightening the nuts.

I was able to get all four cotter pins put in, and considering that there's almost no access to install them, I'm happy with how they turned out.

The fuselage is on the wheels with the engine installed. Awesome.

The prop governor oil line comes pretty close to the engine mount. I'll have to keep an eye on this.

The oil filter looks like it's trapped forever, but there's just enough room to remove and reinstall it.

It took about an hour and a half for us to get the engine bolted to the mount, and another hour or so for me to get the bolts tightened, install the cotter pins, and clean up. All in all, much less work than I thought it would be. Thanks to Matthew, Nat, and Chad for the help.

Preparing to attach engine

Matt — Sat, 09 Feb 2008 22:04:11 +0000

Per the plans, I'm using Permatex #2 sealant on all threaded plumbing that attaches to the engine:

I had to remove the oil filter to install the fitting for the oil cooler return line:

With the filter back on, there appears to be plenty of clearance to get a hose onto this fitting without hitting the filter or magneto. The plans say to use a straight fitting here, but a 45-degree fitting is really necessary if you have an angled oil filter adapter like I do.

A crow's foot wrench came in handy for tightening the fitting for the other oil cooler line. A 45-degree fitting is necessary here too, as others have discovered.

Looking from the left side of the engine, you can see how the hose will go between the prop governor bracket and the engine-driven fuel pump. I may also have to use a hose with a 45-degree fitting on the end – we'll see.

Looking into the business end of a VA-128 restrictor fitting. The end is plugged with a brass (?) insert that has a small passage drilled through it. Using these for the oil and fuel pressure pickups is a smart idea, so that a broken transducer hose won't dump all your oil overboard or pump fuel onto the hot exhaust pipes.

The oil pressure fitting has to be clocked at a 45-degree angle to vertical, so the hose goes the right way and doesn't hit the engine mount. Notice I had to remove one of the clips that attaches the right magneto drive pad cover plate, in order to get a wrench on the fitting.

I propped up the tail with a sawhorse padded with foam rubber. The tailwheel spring is secured to the sawhorse with a bungee cord so it doesn't accidentally get knocked off.

Now the fuselage is roughly level, which will make hanging the engine easier.

I manhandled the engine pallet up onto dollies, and rolled it over towards the front of the fuselage:

Then I levered the whole works up onto the feet of the engine hoist. I'll unbolt and discard the pallet once my helper arrives tomorrow.

Heavy red thing is ready to attach to white thing.

Installed prop governor

Matt — Thu, 07 Feb 2008 03:17:38 +0000

Here's the propeller governor, a PCU500X. This guy is basically an speed-controlled oil pump, which controls the pressure of the oil being pumped through the hollow crankshaft, and thus sets the pitch of the propeller blades to hold the desired RPM. I started to explain this to Mary but she was too distracted to endure another of my lectures about aviation theory, so I just told her "it costs a thousand dollars and makes the airplane go like hell."

I had to cut off the safety wire, loosen the screws, and rotate the shaft to the correct angle to fit Van's cable bracket. Here it is after I redid the safety wire:

I used my cool new Milbar reversible safety wire pliers to twist the new lockwire, and I must say the improvement in my safety wire workmanship is noticeable compared to when I was using the old, cheap pliers. I guess once again I learn that quality tools make a difference.

I wiped down the surface of the governor drive pad, and removed the caps covering the drive gear and the oil ports:

Likewise, I cleaned the mating surface on the governor and removed the plastic plugs from it too. I made sure to take these photos so I don't have to wonder, "did I really remember to remove those plugs before I bolted on the governor?"

The instruction sheet that comes with the governor says to coat both sides of the included gasket with "a suitable release agent". I dithered on this for a while before finding an old RV-List posting mentioning that Van's preferred substance is plain old fuel lube. I guess the idea here is to make it possible to remove the old gasket if you have to remove the governor, and not to put something on there to enhance the quality of the seal (e.g. Permatex).

Then I bolted the governor and cable bracket to the engine, using star washers under the nuts. Due to the clearances involved I had to use a crow's foot on my torque wrench when tightening the nuts, but that was no big deal.

Here's the model info and serial number, in case I ever need it:

Engine stuff

Matt — Wed, 06 Feb 2008 23:58:57 +0000

Still waiting on one last box of parts to arrive before this weekend's building session, but in the meantime I spent some time getting familiar with the engine and planning what I need to do before I bolt it to the airplane.

Here's a view of the accessory case on the back of the engine. Clockwise from the left we have the left magneto (black thing with red wires coming out of it), oil filter, vacuum pump drive pad, right magneto drive pad (unused, covered with a circular plate), prop governor drive pad (with cable bracket in place for a test fit), and engine-driven fuel pump (silver thing with blue fitting cap). The hexagonal silver thing in the approximate center of the accessory case is the vernatherm valve (basically an oil thermostat). Above and to the left of the vernatherm is the oil temperature transducer port, directly above is the tach drive pad, and below and to the right is the supply port to the oil cooler.

Closeup view of the right side of the accessory case, showing the vacuum pump and magneto drive pads, and the supply port to the oil cooler. Also visible is the port for the oil pressure gauge – it's the small hole with a red plug threaded into it, just above the magneto drive pad. (Sorry, all my pipe plugs are the same color as the engine itself, which makes them not photograph well)

Closeup view of the left side, looking past the magneto. Here you can see the return port from the oil cooler, which hides behind the oil filter. In fact I'll probably have to remove the filter to get a fitting on there.

Since this engine has a right-angle oil filter adapter, it uses a CH48108-1 filter, which has a built-in check valve. That should help keep oil changes from becoming a major environmental hazard, which has not always been the case with other airplanes I've owned. These filters are also about ninteen bucks each, but that's aviation for you.

Engine arrived

Matt — Tue, 27 Feb 2007 02:00:49 +0000

This morning I got a call from the freight company telling me that the engine was waiting at the dock, so after work John helped me bring it home using his pickup. Then, he and Scott helped me get the 400 pound crate into the garage. Behold:

Shiny:

More shiny:

Shiny here too:

Mattituck Red Gold engines are built from start to finish by one technician, who then signs his name in gold on the case. Good job, Pat.

Unfortunately the huge crate was taking up more than its fair share of the garage, so I broke it down and put my little card table over the top of it so I can use the area for plans and parts. The engine will hide under there till I need it.

I'm thinking of calling it the "Limited Edition Lycoming Executive Desk". Take that, MotoArt!

Thanks to John and Scott for all the help getting this thing into its new home.

Ordered exhaust

Matt — Tue, 09 Jan 2007 03:35:34 +0000

I called Larry Vetterman and ordered an exhaust system for my engine. It's the same thing that Van's sells for $935 plus shipping, but by going straight to the manufacturer I was able to get it for $850 delivered.

I wanted to use the new kind that has built-in mufflers, but he said the mufflers won't fit if you have a forward-facing injector like mine. Oh well.

Ordered engine

Matt — Wed, 15 Nov 2006 23:32:34 +0000

I ordered my engine from Mattituck today:

TMX IO-360 with roller tappets
ECI Titan cylinders with nickel carbide barrels
9:1 compression pistons
Precision Airmotive Silverhawk fuel injection system
Aluminum oil sump with forward facing induction
Red Gold performance package (included with roller tappet option)
One impulse-coupled Slick magneto
One Lightspeed Plasma III electronic ignition
Skytec high torque inline starter

Scheduled delivery is for the third week in January.