Jur's RV7 Aircraft Factory
3497 hours and counting

Getting into some more systems installations. Today I installed the "sniffle valve".

The sniffle valve is a small, spring-loaded one-way drain valve installed at the lowest point of the induction manifold on the Superior IO-360 engine. When the engine is shut down, it opens to allow any accumulated fuel, oil, or condensation to drain from the intake plenum. As soon as the engine starts and manifold vacuum is created, the valve closes, preventing unfiltered air from entering the induction system. By removing excess liquid from the intake manifold, the sniffle valve helps prevent difficult starts, rough engine operation, induction backfires, and in extreme cases, the possibility of hydraulic lock caused by liquid entering a cylinder.

The location to install this valve is at the lowest point of the induction chamber. In my engine, the two plugs on the top here are entries to the induction chamber. This contains cold air that entered through the throttle/fuel servo.
The fuel could accumulate there after an engine shutdown and cause backfire that kills your airfilter and possible the entire induction system.Installing this simple valve gets rid of this fuel as soon as the engine stops and the vacuum in the induction chamber dissappears. The excess fuel is carried away through a aluminum tube the exist between the exhaust pipe exists.

The fuel will flow back and accumulate at the lowest point For aa 7A, you would choose the front port. Since I have a RV7 taildragger, my lowest point on the ground is on the second port circled in blue in the image below.

As said, a short flex hose followed by an aluminum tube carries the excess fuel to the cowling opening behind the firewall in between the exhaust tubes.
The aluminum tube is held with a single adel cushion clamp in the flange of the firewall. I located the hole so one of the nutplate ears is at the dead center of the lower firewall flange.
The hole of that ear is an existing rivet hole which i drilled out and used as reference for drilling the large center hole for the fastner and the other nutplate ear.
I could not just open the hole for a #12 screw as the existing hole was already dimpled. 

Drilling into the flange is always a bit critical so once I removed the existing center rivet. I made a template in a thick aluminum plate and clamped that to the bottom of the fuselage with one rivet inserted in the hole of hte nutplate ear.

 Drilled the #12 hole and other nutplate ear #40. It's never fun having to deburr holes when there is no access. The lower engine mount bar is seriously in the way of the lower flange and there is no way you can get a drill or deburr tool in there to clean the edges of the inside. So I had to use sandpaper to clean the edges here. Not easy with steel plate but it works.

Ok next problem... dimpling the new nutplate ear. A squeezer doesn't fit here and even the pop dimpler set couldn't get in there. Fortunatly I still have this #40 vise grip dimpler which just fit underneath.

Dimple done... not perfect but it will work fine. Dimpling multiple layers including steel after they have been assembled required a lot of force. I pushed the vise grip as hard as I could here.

 Rivetted the nutplate on. Ready to attach the sniffler valve tube.

 Then I started bending the aluminum line from the port to the firewall. and test fitted it with a clamp to the new nutplate. It's still too long here, it will be shortened in a bit.

 Here is how the line looks on the inside with the lower cowl on.Plenty of space. No risk of rubbing or touching.

 I temporarily taped the flex host to the port to get an indication of height below the port. The flex hose is attached to the tube and later on to the valve with hardware clamps.

 Finally I shortened the exist and bend it down a bit just behind the adel clamp.

 Finally I tried to install the valve in the engine. This is where the nightmare starts again. 
There was just no way I could get this plug removed from the engine. It's probably put in with locktite and even after heating the induction block and trying to remove it, I simply couldn't get any movement in it.
I had the impression my allen key started to get more play in plug hole. That is in principle difficult as the plug is steel and the engine case is aluminum. 
I think it's just the allen key wear out by the excessive force. But I'm not willing to take a risk here and will let Patrick at PMM wingservice remove this for me once the engine goes back for a test run.

Another perfect example how a job that sounds easy ends up in another uncompleted job and frustration.

While working on the upper baffles and the ignition wire passthrough through the upper baffles, I had to measure how long the cables on the magneto ignition harnass actually are and how all of this actually works.

The box in my Superior IO360 engine box came with 2 Champion Slick Magneto's 4371 with impulse coupling on both magneto's.This is how a 4371 looks like:

The magneto's were already mounted on the engine when I received them from PMM Wingservice but the plastic caps were still on. I still have to mount the ignition harness with the ignition wires myself.

I opened the box and found this spaghetti of wires. I kind of worried on how to install these but it's pretty straightforward. 

Each magneto head contains 4 wires, 2 wires go to the top cylinders and 2 go to the bottom cylinders. Eg one ignition harnass has the wires for Top cylinder 1 and 3, and bottom for cylinder 2 and 4.
Which cylinder to connect to is marked on the end of the wire on the nut that connects to the spark plug and has markings in this case like T1, T3, B2 and B4.

You can also see in the image below that the cover that is visible with the springs has LH marked on the head which is for LeftHand magneto.
The orientation is always seen from the pilot see forward. So LH is the magneto on the pilot side, RH the magneto on the passenger side.

Then the question is how these mount on the magneto rear side. After all, the spacing of the spring contacts is equal and you could turn is in 4 possible directions. It is important that firing happens in the correct order or you ruin your engine.
Well the good news is, you can't actually mount them wrong. If you remove the plastic cover cap to replace it with the real harnass, you will notice that the screw on the cap form a triangle. One of the sides of the triangle is longer than the other 2.

So if you measure where holes in the harnass are wider and mount them in the same position as the long side on the plastic cover was, you can't go wrong.
If you go wrong, you won't be able to screw back all screws into the rear of the magneto. If all screws fit correctly and you can torque them, you have the orientation right.

 In the box, you also get some tyraps and some clamps and plastic inserts which are used to route the wires along the cylinder heads for the bottom wires.
I like that, but question is where the wires for the egt and cht sensor should go. I have to think this over.

With the baffles on, and as I want to get these finished before painting, I also had to think about magneto cooling ducts.
I looked up some builder references but the best image actually came from the RV14 installation manuel. This is a very good reference manual for firewall forward work as it contains much more information than the RV7 manual.
Here is a screenshot from the magneto cooling blastis as proposed on the RV14. It gives an idea on the routing within the engine mount, the location of the hole in the upper baffles and the location of ending the cooling tube on the magneto.
As seen here, you want the cool blast tube to hit the rear case to cool the electronicts of the magneto.
There is some debate whether these are really necessary but in my opinion you can't really take any risks on the primary parts of your engine. The cooling air will reduce wear & tear. It's hard to put a number on it, but magneto parts, points and even springs often fail from heat related issues. The hottest points are the coil and the area around the distributor housing. Cooling air aimed at the body of the magneto, especially around the distributor housing, helps reduce internal temperatures overall.

The pilot side magneto blast tube location is pretty straightforward. There is not a lot of options and the best location is probably the one as indicated on the RV7 baffle kit plans. The pilot side ignitiion wired pass right next to the oil cooler opening on the CB-705A cylinder 4 aft baffle and just below the CB705-B oil cooler brace so that area is out of choice. The next option is on the upper left  corner of the CB-706A left aft case baffle as seen from pilot side. 
On the passenger side things are a little more "free to choice".
I tried out various location like the one shown below, Things to look at are the distance from the engine mount, curved direction towards the magneto and where the bottom ends up in the most natural way.
The tube is attached to the engine mount with RTV and also at the magneto case.

 First I made the hole for the blast tube on the CB-706A pilot side. The opening is just below the flange of the plenum roof and next to the intersection of CB-706A and CB-705A.
The best way to do this is to use a step drill. The tube is 5/8 duct tube, also used as the conduit for wiring in the wings and fuselage.
The hole to drill only has to be as wide as the inner ribbles on the duct tube. 5/8 is the outer diameter of the duct, the inner ribble is only 11/16", so drill to 11/16 size for a snug fit.
This ensures the tube is stuck into the hole and can't move. Some additional RTV will keep it in place and seal it off.

 The I also drilled the passenger side opening which is a little more outboard than the one indicated on the plans.

 I test installed the tube on the pilot side and verified routing.The tube curves passed the engine mount where I will attach it with RTV. and it hit's nicely on the rear of the magneto case where the notch in the case is located.

 View from the front where you see both magneto cooling holes.

A big day again in my project. Nothing substantially done but I have hung the propellor on the engine prop hub for the first time.
I kind of wanted an idea how everything would fit together and what is delivered by Catto with the propellor, spinner and saber extention.

I have a 4 inch Saber extention, spool type. This is required for the Sam James cowling installation.
It took a couple of tries to find the way to do this but it's pretty self explanatory once you understand things. The spinner is predrilled and cut and the holes in the spinner plate are also made with nutplates installed. This makes it pretty simple.

Short bolts hang the spool to the prop hub behind the starter flywheel. You bolt these in in a star pattern. I am just doing this temporarily so there is no torqueing involved yet. This will come of a zillion of times. The long bolts holding the propellor and everything forward of the spool extentions are very long. The threads also extend quite far through the extension. This is probably for having enough space if an additional weight plate has to be added up front.

Here is a view with the prop bolted on. This is pretty damned cool seeing this a first time.

Front picture.

Milestone day ! 
This is one of those days that you know mark the timeline of building your airplane. The moment you hang the engine in the engine mount.
After many days of thinking about missing any things on the firewall, I came to the conclusion that this is the right moment to hang the engine and move on to the firewall forward work. There are some more things I need to do on the firewall, but it's not possible to be sure about the exact location to drill large holes in the firewall until I can actually evaluate the position with the engine in place. i'm thinking of the mixture and throttle cable and alternate air cable. Other than those, I'm pretty sure everything on the firewall is in place.

The same thinking goes for the rear of the engine case. Make sure the 45° restrictor fitting for the oil pressure is mounted in the engine case prior to hanging the engine. It's almost impossible to install this once the engine is on the engine mount. Mine was already installed by PMM during engine assembly. While you are at it, also install the other oil cooler fittings in the engine case (in and out). These can also be done later but it's easier now.

First step was to remove the safety straps that held the engine to the wood pallet that was used for transport. I want to keep track of how this was done as this engine is a brand new engine that has not yet been on the test bench. When all is ready, I will need to unhook the engine and bring it to PMM Wingservice to have it running on the test bench for a first time. This has the disadvantage of extra work on removing the engine and all connections again and having to do it again after it has been run. On the other hand, the major advantage is that I do not have to worry about corrosion and idle time of the engine as it has not yet been running. The cylinders are as if they would be in a stock location on a bench waiting for an engine. There has been no movement of the cylinder heads on the cylinder walls and everything has an oil film on it as delivered from Superior Air Parts. Whether building takes me another 3 years or just 1, it won't matter. I'm gladly willing to take that extra work knowing there is no pressure.

The engine was protected well on the front and rear crankcase and supported in the front under the front with some wood block supports. I'll have to keep all this in stock so that I can re use it in the same way when I bring the engine back to PMM.

Using the engine hoist, we pulled it up, removed the pallet and moved it over to the front of the airplane. Alain helped me on this task to keep the engine in position. It's best having some extra hands around when you do this as the engine is heavy and the bolts are not always willing to go in as easy as you think it would. 

The last part of the moving is the most critical as you don't want your magneto's or fuel pump to bump into the engine mount. Having one person moving and another one guiding the engine is no luxury.

Also notice I leveled the airplane in flight mode. This is much easier to position the engine than if it would be sitting on all tyres which would require you to position the engine at an angle. This leveled way makes it much easier.

I found some documentation online from someone who did this before and described the process. I studied this carefully and upfront, had a close look at the barry mounts and dyna bolt set. You can read it following this link https://www.myrv14.com/buildlog/20150917/Engine_Hanging.pdf. Vans Aircraft also has some drawings available which are not part of the standard plan set that you receive with the kit. 

Study the plans carefully, the barry mounts have to be positioned so that the engine rests on the compression side in the bottom and the compression side in the back on the top mounts. The compression barry mounts are the ones that have a step in the rubber. The non compression ones don't have the ribble on it and look like plain rubber. If I remember well, the non compression ones also are a little larger. Also take care that the washers are in the correct locations. The barry mounts come with one big washer in the box. It's good to assemble the order of all this before starting to move the engine and have thing prepared well. I colored the position of the large washer red in the picture above.

There are 2 lengths in the dyna bolt kit. 2 x AN7-43A and 2 x AN7-44A. The longer ones go on the bottom side, the shorter ones go on the top. The difference is not much more than the length of one of the washers.

Start with the 2 top bolts. The first one is very easy... tighten the bolt but don't torque it yet, you'll probably have to loosen them again working on the bottom bolts.
You do need to tighten the first so that the barry mounts compress allowing the other hole to come in line with the engine case. Remember this is a dynafocal mount, the bolts point inwards. If the bolt is not tightened enough on one side, it's impossible to insert the second one. As you tighten the bolts, the barry mounts compress and also position themselves in the engine mount. That's important.

What I found very annoying is that you can't put a socket on the bolt head as the engine mount is in the way.  I used an extension on the wrench but that didn't make it easier.

The engine sometimes needs a bit of persuasion to get it in position :) Although I don't think this did much. Found out later it's more important to tigthen the other side and use the engine hoist to lower or lift the engine a bit in order to get a bolt in.

The large washer goes between the compression mount and the crankcase as a spacer for the bottom mounts. On the top mounts, I have put that washer on the compression mounts under the bolt head as you can see in the image below. The image has both top bolts in place and tightened.

From there on, things went less smooth and it took about an hour or 2 before I got the last bolt in so I did not take any more pictures until it was done.

I'll try to describe the further process I took.

As both top bolts were tightened, I lifted the engine a bit using the engine hoist. This allowed me to slip the barry mounts between the case and the engine mount. Don't forget the large washer between the barry cookie and the engine case. Don't forget the compression side of the barry mounts is against the engine for the bottom mounts. Then I lowered the engine again and after some wiggling I was able to put the 3rd bolt in. I did have to loosen the top bolts a bit though. 

The fourth bolt is the most difficult one. Looking with a mirror through the hole there was no way the bolt would go in. After a lot of moving up and down, I finally discovered my problem : the washer between the barry mount and the engine case was not aligned and the pressure on it is high enough that it makes it hard to move it. After lifting the engine a bit and tapping on it, I could get it more or less into place. 
A second trick I used was to take an old bolt which was smaller in size and grind down into a guide pin. Once I could slide that smaller bolt in, I was able to wiggle it around in order to get that washer and the engine hole into alignment. I put some grease on the final bolt shank and finally was able to put it in with only very light tapping of a rubber hammer.

I was feeling relieved as I bolted the final nut on that fourth bolt.

As final step, I torqued the bolts. These are AN7 which take 450 - 500 inch/lbs. I used the middle value of 480 inch/lbs. The engine will still need to come off as mentioned earlier but the position of the engine is very important when installing the cowling so I torqued it to the final value.

Took some pictures of the plane with the engine in place. This surely is a big milestone and is a "feel good" moment during the build.

Happy camper...

As I had some time left, I took out the fuel throttle body. This comes with a plastic spacer.

The orientation of the throttle body was a bit of a mystery at first but soon figured out what side was the throttle lever and which side the mixture. 
In the image below I installed it on the forward horizontal induction air intake at the cold sump of the engine. In the image below, the throttle lever is the gold colored arm.

Finally I covered the intake with some paper and masking tape in order not to get foreign objects entering the engine.

End of a productive day was off course celebrated with Alain with a good strong Belgian HQ beer.