Attaching the Engine - Part 1
TLDR
- Installed the Engine to the firewall (not fully torqued yet)
Details
Today I mounted the engine! To mount it, I dragged my wife Ye to the hangar to help. This is a big milestone. I was dreading of this task but it went smoother than I expected.
We spent the better half of the afternoon in the hangar for the work. My friend Kevin (who’s also building a Sling TSi!!) happened to be at the airport too. I was so glad he was there, because I ended up borrowing some tool from him to complete the work :)
Separating the Engine from Transport Pallet
The first step of the work, was to separate the engine from the pallet. It was connected through 2 brackets (8 x M10 bolts).
To remove these transportation brackets and bolts safely, we needed to hang the engine onto the engine lift first. I used a Harbor Freight 1 ton lift for this job.
Positioning the lift’s hook directly above the engine turned out to be a little challenging. I had to manuever the 2 legs of the engine lift directly below the pallet. And in order to do that, I had to lift the pallet first.
I lifted the pallet using the pallet jack I bought from Amazon earlier, then moved the engine lift in place (perpendicular to the pallet jack). The whole thing felt like playing Tetris.
When connecting the engine lift to the engine’s lifting mounts, my Harbor Freight engine hook was slightly too big and it chaffed on a bolt on the engine. I didn’t want to risk anything, so I ran to my friend Kevin’s hangar to borrow the hook he used to mount his 916 engine. And that worked beautifully. I went to Amazon to buy a few more for future use.
I got too excited and forgot to take a picture when they were first connected unfortunately. Here is a pic once the front bracket was removed.
That Rivet
With both the front and rear transportation brackets removed, I started to work on “that rivet”.
So there is a AN6 nut welded to a small bracket, then riveted to the turbocharger’s bracket, right behind the lower right engine mounting position.
In order to install the engine to the airframe, Sling wants to remove that AN6 nut, and replace with an M10 nut. This means I needed to removed the small bracket connected through the rivet.
Due to the position of that rivet, it’s a pain in the butt to get it off. After consulting with many builders on the Sling Builder group, I decided to try drill it out when the engine was suspended in the air.
I started with a 7/64” drill bit, then upgraded to 1/8” bit, then to a center punch. It actually wasn’t too bad. I had to be extremely careful to not damage the painting on the engine mount itself, but it only took me about 10 minutes to get the rivet off.
And once the rivet was off, the small bracket with the welded nut fell right off.
Hanging the Engine
Then Ye and I worked on actually hanging the engine to the firewall.
We did some initial prep and wrapped the wires harness in a bubble sheet to protect them from accidental chaffing. Then adjusted the engine lift’s height to be roughly the same as the airplane and got the holes aligned.
All 4 holes lined up almost perfectly. It didn’t take much effort to insert the bolts.
I removed/re-inserted the bolts several times for test fit and ensure the washers/rubber mounts/etc were in the right order.
Another thing I did was to replace the nylon locknut to high temp metal locknut. The locknut is going to be in the engine compartment and I’m really not confident the nylon will withstand the heat from the engine. Besides, one of the locknuts will be less than 1/4” inch away from the turbo. According to AC43.13-1B, the heat resistance upper limit for nylon locknut is way lower than what a turbo can generate. So I purchased a set of high temp metal locknut to replace the nylon ones.
The Sling instruction says the bolts’ torque = 38 nM when oiled. I made a mistake here and greased the bolts instead of oiling them. With grease the equivalent torque would be 30 nM. But since these bolts are so critical I didn’t want to deviate from the instruction. I torqued the bolts to 15nM temporarily. I will have to remove all bolts and thoroughly clean them with acetone, then soak them in oil to get the proper torque value.
Cutting the Lower Bolts
The bolts that came with Sling were super long. Both of the lower bolts needed to be cut short about 6-8 threads in order to be installed. As a reference, when I torqued them to 15 nm, the lower right bolt was almost touching the turbo housing.
So I put them on a vise, and cut them with a 2 inch cutting disc. Then I deburred them with scotch-brite wheel on my bench grinder.
90% Done, 90% Unfinished
As we cut the bolts and attached engine half torqued, we were almost into the evening.
So we decided to keep the engine lift still attached to the engine as a precaution, and we wil come back next time to finish the torquing then hopefully we will be able to start connecting the wires and hoses!
As always, so much got done today and there are still so much to do!
