Engine Installation - Part 4

I shifted my focus to the installation of the engine wire harness, routing and securing it to the engine mount and passing wired bundles through the firewall to the ECU.

I spent several days laying out the wire bundle in different ways trying to see how the bundles would fit and if there was sufficient length to attach existing terminations, like fuel pumps, primary connections for the ECU and the fuse box mounted to the firewall.

I used many Adel clamps to secure the wire harness to the engine mount at multiple locations as I routed multiple bundles towards the firewall.

I wanted to keep the bundles as close the engine mount as possible so that I would have easy access behind the engine.

I also wanted to minimize the number of wire bundles jumping from the engine to firewall components.

This has the added benefit of soaking up the excess length in the harness, that I would have otherwise had to create a service loop that would get tucked away somewhere.

 

 

 

Some wires like the voltage regulator, solenoid valve assembly were just easier to loop the cables back on the main harness and jump across to the firewall.

I think I could have gotten the voltage regulator to follow the rest of the harness but I think overall I have achieved a secure harness and optimized the wire paths.

There are two common issues with installing the wire harness to the sling TSI, which are the fuel pump connections and the throttle body connections. In each case, the problem can actually be solved by removing some of the wire loom wrap installed at the Rotax factory.

The fuel pump connectors terminate to fuel pumps inside the fuel pump assembly box on both sides.  The first problem is that one of the connections is too short and many builders cut these wires and extend them.  I wasn't opposed to doing this if needed but one intrepid builder discovered that if you cut back the wire wrap on the bundle you can actually gain a few extra inches by separating it from the harness.

Carefully cutting back the wrap I was able to confirm that there was several inches of wire in the bundle which was all I really needed.  I re-wrapped the bundle using 3M wire loom tape similar to what the factory uses and the bundle is back to looking like new.

 

 

 

I used some small Adel clamps to secure the fuel pump wires to the exterior of the fuel pump box. This will keep the wires stable and minimize wire fatigue due to vibration.

The ground wires were routed behind the fuse box and attached on the terminals on the side.

The Deutch connector for the 3-phase power from the stater was routed straight across to voltage regulator A.

Cannon plugs installed from engine harness X1 and X2 and one from the VPX controller in the avionics bay.

The throttle body position connectors aren't quite long enough to reach the throttle body once installed with the intake hoses so I needed to cut back the wired loom material.

I cut back in a straight line about 2" from where the wires emerge from the bundle.  This allows at least two more inches of length that are needed to connect to the throttle body without over-stressing the wires.

I re-wrapped the bundle using 3M wire loom tape, similar to what the factory uses and the bundle is back to looking like new.

Engine Installation - Part 3

The firewall forward kit ships with a new tail pipe extension that needs to be fit to the muffler that ships with the engine. In order to install the new 90 degree extension you must first cut off the existing tail pipe which feels absolutely crazy to do on a brand new engine.  So, lets get after it!

The instructions are pretty basic for such an important and potentially expensive mistake.

 

 Pipe marked for cutting with large 4" cutting wheel

This cut goes all the way through removing the straight pipe. I cut just above the welded line and skipped the step of grinding down the factory welds

 

 

 

 

 

First cut finished and partially de-burred using eye protection, cut resistant gloves and a face mask, this step produces a lot of dust and sparks from the cutting wheel.

 

The next cut mark is 32.4mm measured from the base of the pipe. You can only cut half way through this next cut otherwise you will cut through the support shroud which would be bad.

I also used the 4" cutting wheel to cut off the lower section of the pipe so I had access to the inside the pipe for the next step.

 

 

 

There is still half the pipe still to be cut under the support shroud that needs to be removed using a small cut wheel on a Dremel. 

Removing the lower part of the pipe cutting just under the should gave me the access shown here to cut out the last piece.

 

You end up with three parts at the end that look like this.

 

Next I de-burred all of the surfaces so that the new down pipe would fit on smoothly.

With the pipe testing fitting completed I used the supplied hardware to clamp the down pipe in place.

There are two different sized clamps that ship in the kit, the larger of the two is on the outside that locks the down pipe to the shroud.

The second, smaller clamp goes on the inside.

Tip #1
The bolts supplied with the kit are one time use, and will likely gall the threads if the hardware has been fully tightened, and you might need to source suitable replacements if you attempt to remove them later.

Tip #2
I had an issue with the inner clamp because the bolt shank grip length was too long and I could not get the clamp to fully tighten around the down-pipe and the muffler. I ended up getting a new bolt with a shorter shank that allowed me to fully tighten and secure the new pipe.

Engine Installation - Part 2

Mounting the engine was actually a pretty quick activity, preparation is key to completing this task to minimize the amount of time the engine is hanging so far from the ground.

 

 

Although it is not mentioned in the KAI you need to shorten one of the engine bolts that is installed near the turbo.  Failure to cut this bolt will likely result in the threaded end likely coming in contact with the turbo.

I shortened this bolt down to 123mm based on recommendations by other builders.  I think the acceptable range is between (123-125mm) in length.

This also made it easier to insert a wrench when tightening the nut later on.

 

 

 

 

 

Bolts, cup washers, lock nuts, and M10 washers temporarily assembled and set aside for securing the engine when I was ready to go.

Tip #1
If you haven't already headed my warnings to remove the shipping nut on the engine side of the mount now is the time, otherwise you will be fighting with the engine suspended in the air trying to remove this nut.

Engine isolation mounts were a little annoying to get them to seat in the firewall forward side of the engine mount. I used some liquid dish soap to help get the isolation mounts installed squarely. I also used a rubber mallet to fully seat the bushings once I had them squarely inserted.

Tip #2
Do not remove the bushings from the packaging until you are ready to insert them, as they are different soft vs. hard materials.

With the engine lift lined up I removed the shipping supports from the engine mount and lifted the engine into position.

At this point I learned the hard way that I should have removed the shipping nut from the engine side of the mount.

 

 

The load spreader made it very easy to line up the bolt holes without the need to twist or manipulate the engine while trying to insert the bolts.

Another view of the upper engine mounts with the bolts, cup washers and M10 bolts started.

I used a star pattern to tightening the bolts until the isolation mounts started to compress.

 

 

The nut on the turbo side bolt is impossible to tighten without modifying a wrench that can fit in such a tight space.

I sacrificed a 17mm wrench that I bought at the hardware store and ground it down over the next hour to get the right shape where the wrench would even fit in the lower mounts.

Both lower bolts will require a modified tool to fully torque to spec.

You will not be able to get a socket on these due to interference from the turbo and the muffler.

 

Here is a closeup view of the turbo side nut and the tight space constraints.

You can also visually see how the threaded end of the engine mount bolt would hit the turbo if not shortened.

Here is a view of the left lower engine mount that overlaps with muffler. There wasn't away to get a socket on this nut because the muffler interferes as the nut is driven further on to the bolt.

Even the steel surrounding the nut blocks a standard wrench from being used, for this reason sacrificing a 17mm wrench is essential.

 

Bolts were torqued to 28ft pounds and marked with torque paint.

I slowly removed the engine hoist lifting force on the engine and allowed it to rest on the engine mount assembly.

I left the hoist in place for a while with the chains slightly slackened until I was confident that the firewall and fuselage were supporting the weight without issues.

Tip #3
Make sure you check your tire pressure on the nose wheel, min wheel was under inflated and with the added weight of the engine the plane it was not stable carrying all that weight on the wheel.

Engine Installation - Part 1

 Installation of the engine begins with unboxing of the Rotax 915 from it's shipping container.

There are multiple packages inside the container so I completed a quick inventory:

Rotax 915 engine - ✅    Fuel pump assembly - ✅    Rotax Fuse Box - ✅    Oil Reservoir - ✅

Engine CPU - ✅            Wired Harness kit - ✅         Engine Maintenance booklet - ✅ 

Coolant Flange - ✅

With all of the accessories out of the way I could unwrap and inspect the engine.

I didn't have a engine hoist or access to one so I had purchase a lift and load spreader from harbor freight.

Surprisingly multiple stores in my area didn't actually have any in-stock so I had to drive to a store in downtown Seattle to collect my prizes.

Pittsburgh 2 Ton Engine Lift

Pittsburgh Load Leveler

Several hours later...

With the lift fully assembled I was ready to lift the engine out of the container.

I didn't purchase the Rotax approved lifting hardware, which I think is ridiculous that it's not included with the engine.

I modified some shackles to fit the lift points on the intake manifold.

In the photo above I had to grind down one side of the shackle so that it would not bind against the intake manifold. Both shackles needed one side heavily ground down in order to fit.

I am sure there are multiple ways or different parts one could use, but this was what I had on hand and I made it work for me.

 

 

Tip #1

The manual calls for this step later in the engine installation but I opted to pre-install the Sling provided coolant flange.  Start by removing the 90 degree flange that ships with the engine and install the replacement part provided in the firewall forward kit.

 

 

With the engine stabilized with the load spreader, I unbolted the engine from the base of the shipping container.

There are (4) 17mm bolts holding the engine to the shipping container.

The engine is stable on the mounting hardware and probably was not at risk of tipping over but I didn't want to take any chances.

Tip #2

After removing the mounting hardware (heavy steal plates) attached to the engine, there is a shipping nut that needs to be removed prior to mounting the engine to the firewall.

The shipping nut is held in place with a welded plate and a rivet as shown,

I drilled the rivet out and with a little persuasion (hammer and screwdriver) the shipping nut was removed and the installation could move forward.

Firewall Forward - Part 2

With my engine delivered and a quick inventory of all parts and condition completed, I can now continue the firewall hardware installation.

 
It is far easier to install of these parts prior to mounting the engine and I highly recommend this approach.

 

I started with installing all of the runner isolated rubber posts that will mount the engine power management module, master solenoid, and starter relay.

 

 

 

Engine fuse power management controller mounted.

 

 

 Starter relay installed

I also needed to cut out the sound deadening material for the master solenoid and installed some M5 rivnuts with JB-Weld.

I used the based plate of the solenoid to create the template to cut out the required material from the firewall.

I used the base plate to match drill the holes and up-sized for M5 rivnuts and used stainless hardware and washers to secure the solenoid to the firewall.

 

 

 

 

Solenoid installed, there should be enough clearance for the the main wires from the battery and the attachment cams for the cowling.

 

I opted to leave the fuel pumps for the Rotax 915 in the factory location and with new fuel manifold installed this should keep all of the fuel lines and routing nice and neat. I will cover more of the installation of the fuel pumps wiring and fuel lines in another post.

The last part prior to installing the engine is the voltage regulator and heat sink that shipped with the firewall forward kit.

The unit was wired up to the engine fuse box and secured using Adel clamps to the engine mount.

 

 

This completed the hardware installation prior to mounting the engine.

Tip #1
During the installation of the engine I ended up removing the voltage regulator to allow more room to access the bolts for the engine.  The heat sink has very sharp edges and I was frequently scratching myself on this part so it had to go and was re-installed later.

Firewall Forward - Part 1

With my engine due to arrive in the next few weeks I began the installing hardware I had on hand from the kit as well as a few parts that ship with the kit from MidWest Panel Builders.

 

The overflow bottle was installed as well shunt and shunt cover.

The shunt cover is made from very brittle plastic and I can see why others have broken theirs during assembly or simply run into it and cracked it.

This will likely get replaced with a 3D printed version with an inspection cover in the future.

The oil reservoir was installed after powder coating, probably a little overkill because the majority of it is covered by the reservoir itself.

The brake reservoir that I received with my undercarriage kit comes with a mounting plate so it can be riveted to the firewall but unfortunately my bracket was bent backwards and didn't align with the holes pre-drilled in the firewall.

I ended up purchasing a new one from Matco directly as it was only a few dollars plus shipping and the problem was solved. MCR-002

Next up was the battery tray, that after a visit for powder coating it was assembled and mounted to the firewall.

Next I moved on to the NaviFlow Fuel Manifold sold by Aerospace Innovations.

I order one of these after seeing it in person at MidWest Sky Sports.

The kit also comes well packaged and has everything you need to install it.

I used the template to overlay on the sound deadening material so I could make a pattern to cut away the material so the back-plate can be directly mounted to the firewall.

The sound deadening material cuts easily with a sharp razor blade, from there I slowly removed the material to tried and get as much of the adhesive backing off at the same time. I failed...

For the adhesive that remained, I used some adhesive remover and plastic razor blades from Amazon to scrape the rest off.

 

The kit didn't come with instructions at the time so I called Henry at MidWest and confirmed that the template should be shifted to the left up against the stiffener as shown.

Next I match drilled and up-sized the holes and installed M5 rivnuts with JB-Weld to secure them in place.

 

 With the adhesive cleaned I was able to test fit the back-plate against the firewall.

The last part I had available was the circuit breaker block that mounts to the firewall and comes in the wire harness kit from MWPB.

I used the breaker block to mark the mounting location on the firewall and cut away the sound deadening material.

I reviewed where others had their circuit breaker boxes installed and considered where the wire harnesses which are the two holes to the right protrude allowing enough space for wiring the individual breakers.

I match drilled the mounting holes through the firewall and used M5 rivnuts with JB-Weld to secure them in place.