Firewall Forward and engine

Prepared Firewall for engine mounting. Conscious that I needed to get as much as possible fitted and holes drilled before the engine gets in the way! Fitting the foam and firewall components was fairly straightforward. Provisioned 2 x M4 rivnuts and a space for the Midwest Panel fuse box that will be needed later. Some got ya’s along the way. The fuel return lines now go on the left of the firewall. The installation manual shows 3 holes on right but my plane only had 2. The fuel pump power connector needs to be extended, but which one, which one is main and which one is aux. Which is A and B? It seems that the top pump on the Rotax pump box (when mounted upside down) is the main A pump and the lower is Aux Pump B, so pump B line needs extending with high temp cable. I used double heat shrink and staggered the connections, then added some harness weave on top to match the rest of the harness. Useful to get the heavy electrical cables (4 – 6 AWG) installed or at least ready before engine mount. Add cable to the starter motor and engine block ground lead. Rented an engine hoist, all went fine until the last nut! Some points to note, that may help others who follow later. Rubber mounting bushes are a tight fit. (Note two different types – hard and soft rubber). They need to sit well down in the engine mount, Fairy liquid helps. Do this first otherwise, you will think like I did that the bolts are too short. (Bottom 2 bolts need to be cut to 122 mm to avoid interference with engine). (2 hrs of unnecessary work). Bottom right fixing at turbo. My engine, as shipped had a captive metric fine thread nut riveted on a plate for shipping (pic). Spent ages trying to bolt my metric coarse thread to it!! Needed to remove it (drill out rivet – hard to get to) and use the correct kit M10 nyloc nuts. Even so, it’s hard to torque up the bottom right bolt. After the engine was mounted proceeded with some plumbing. Intercooler – placing baffle and hose cutting straightforward. The baffle fibreglass mounting holes need drilling out to about 20 mm for the grommets.

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