Patrick's Sling TSi

Weeks 109-112: Engine install

In the last couple weeks I passed the significant milestone of getting the engine installed. I was able to borrow a hoist from a friend, and on the advice of a local Rotax mechanic used slings instead of the lifting brackets called out in the engine installation manual. I put one sling around the frame at the rear of the engine, and another one around the gearbox assembly.

After a little experimenting I had them adjusted so that the propeller end of the engine was a little higher than the back. This let me get the top bolts started first, then I could lower the hoist to allow the bottom to swing down. The biggest challenge during this part of the process was getting the rubber isolators properly seated in the engine mount.

I think the holes in the mount are designed to match the isolator diameter exactly, but the powder coating process causes them to be a little small. To get around this I used my bench grinder to put a slight bevel on the rubber isolators so they would properly get started in the holes. This worked pretty well, all the isolators then pulled in properly when the bolts were tightened.

The top bolts were easy, and the bottom bolt on the left-hand side was not too difficult even though the nut needed to be put in a narrow part of the engine frame. The bottom bolt on the right-hand side was much more difficult. The nut had to be installed behind a curved part of the frame holding the turbo charger. I had so much trouble with it I was questioning if I should use the temporary nut mounted to a swivel plate that the Rotax factory uses to attach the shipping bracket.

Eventually I was able to get the nyloc nut started with one finger, then I was confident enough to drill out the rivet holding the temporary nut which allowed me to get a wrench on it from the other side. For this nut and the other bottom one I had to modify a 17mm wrench by grinding it down to where it would fit in the tight spaces. I was able to take off enough material so that it could fit, but still had enough strength to get everything torqued properly.

The other minor issue I had was finding the torque values. The firewall forward instructions just say to reference the introduction manual for the torque values, but both my physical copy and the latest electronic one on dropbox only had values for AN hardware, not for the M10 bolts used on the engine. The Sling factory support sent me a chart that had the correct values, as well as some other things I will need later.

Importantly, the instructions they sent said the torque values require the bolts to be lubricated. I ordered some copper anti-seize and while I still had the hoist connected I removed each bolt one at a time to apply it. With everything properly torqued I disconnected the hoist.

Once the engine was on I ran the attached wiring to the proper locations and got them connected. The ECU was a little difficult since I had already installed the top skin that covers that area. I had to contort myself into position to get to everything from the bottom, but I did manage to get everything plugged in and the ground wires attached.

In the last week I have been cleaning up some of the wiring and starting on the rear inside skins. I also got some wire in to connect the heater to the control switch. I found a connector to mate up with the plug on the heater assembly, but when I was installing the wires in the connector I realized I didn't have the little clip that holds everything in place. I decided to cut up a zip tie and super glue those in to hold everything. That worked great, but when I plugged the connector into the heater assembly I found that the attached wires could be pulled through the fuselage rib to where I could have just directly plugged spade connectors onto each terminal.

I did a mockup of the bottom cowling to see how it was going to fit. One question I had was if anything was going to attach at the front of the bottom fuselage. The cowling does not go back that far, but I don't want to leave the firewall insulation exposed at the bottom, so I am going to put an angle on to cover that seam.

I also started (again) on the brake lines, but after several attempts and kinked plastic lines I decided to order metal lines instead. I think this will be better anyway. The next step is to get the brake lines installed so the rear floor can be closed up, then I can put in the center console parts and start on the fuel selector and throttle/brake assembly. I am also going to start on all the other components that need to be attached to the engine.

There is still quite a bit of work to do but it is getting closer, and with the engine on it looks a lot more complete.

This post is from Patrick's Sling TSi