Today was a big day. I finally got my Rotax 914UL2 installed on the plane. I’d be lying if I didn’t say that I was extremely nervous seeing the engine hanging about 3 feet up in the air, but all went very well. I was even able the manage the install all on my own without too much trouble. The firewall forward manual says absolutely nothing about the engine installation, but the Sling 4 Maintenance Manual (available from the TAF web site) has some great info on this as well as a host of other things. A few important things to note are that the torque value you use which is 38Nm (28ft lbs) is the lubricated value because you use a bit of engine oil on the bolt, so don’t just assume a dry torque value for a M10 8.8 grade bolt. (EDIT 11/25/2018: One thing to add is only use engine only if you don’t want to calculate your own torque value this is because other lubricants may provide more or less friction while tightening). Another item to note is that the 130mm bolts that are provided are a little long. The maintenance manual says to shortened them to 122mm. I suppose maybe the top bolts would be fine, but the right bottom bolt is fairly tight and would be too long if you didn’t shorten it. Also I followed the recommendation for how to install the bolts, even though the bottom bolts are actually put in backwards (in regards to what the FAA says to do). There is also a note in the MM that you don’t use washers on the nut side of the bottom bolts, though the kit provides washers to do this.
The 130mm M10 bolts need to be shortened to 122mm as per the Maintenance Manual.( original on the right) I suppose that really the lower and mainly the right lower bolt needs to be shortened, but it doesn’t;t look a little nicer not have a lot of excess bolt sticking through. The job went pretty quick with the dremel.
I took the side off the box so that I didn’t have to lift the engine over the box and it was a bit easier to get to the engine to loop the ropes through.
I double roped it just in case. It really wasn’t an issue though. The engine is very light (only around 100 lbs.) and the ropes barely looked like they were holding anything. I gave it a quick test with the crate bottom still bolted to the engine just to make sure it was balanced and that the ropes would hold OK.
No washer on the nut side of the lower bolts because the exhaust bracket is there. I torqued it from the bolt head side so that I didn’t scratch up the bracket (in this photo the bolt isn’t completely torqued). The right side is a pretty tight fit on the nut side and probably was the most difficult to get on. I also removed the oil tank so I could get the torque wrench on the bolt.
Top bolts (not torqued yet). I rotated tightening the bolts rather than one bolt to full torque at a time.
And it’s on. Not too bad. I found it easiest to pull the plane towards the engine to get the bolts to seat in rathe then the engine to the plane. The hoist made it very easy to get the engine to the right height.
Well the external alternator didn’t come with any instructions so I used the parts list diagram to figure out how it goes together. I also found that the Rotax Install Manual has a sparse diagram as well, but the parts list is a bit more detailed. I want to alodine the arm bracket so I don’t put that on yet and I didn’t torque anything down because I’m not sure what I should torque it to. Jean alerted me to the thin washer (#14 in the diagram) and to make sure it’s put in the correct place, they had put it on the other side of the joint and the alternator mount actually broke over time because there was tension on the bracket. It’s a very thin washer so not really sure how that would cause that kind of issue, but I’ll trust him on that :-).
The two bolts in the front of the gearbox housing cover (I guess that’s what you call it) get replaced with longer bolts provided in the alternator kit (from Rotax). The original that was taken out of the engine is on the right.
These are the two bolts that need to be removed and replaced with the longer bolts.
It’s pretty much together. I want to see if there’s any special torque values that I need to know about. Maybe the two bolts that go into the gearbox housing cover need to be torqued to a certain value. Also a few bolts need to be safety wired. I also use two large black bolts that came with the alternator to temporally hold the large pull to the main engine shaft. I don’t know what these black bolts are actually used for since I can’t find them on the parts list diagram, but I’ll check around more.
NOTE (11/24/2018): I just found the following referencing the part list diagram. I found this from the California Power Systems site.
So there’s a few torque values.
NOTE (12/5/2018) Also found torque values for the two socket head screws that hold the alternator bracket to the front on the gearbox housing. Those are torque to 10NM or 90 in. lbs.