Firewall penetration question

[Charles in SC]

I am going with a new Experimental IO-360 from Van's. My question is this: are the penetration points called out on the plans where they should be or should they be "adjusted" some.

Where is a good place to penetrate it for a wiring hole? I have one of Avery's pass throughs.

 

[shuttle]

Charles,
I'm building around an IO-360-M1B. The FW penetration locations on the plans seem reasonable to me. The only one I would be inclined to move a little is the fuel line passthrough. It comes out pretty close to the starter contactor.

I'm going with two wiring passthroughs - one for power wires and another for sensor wires. I've put them high up, one on each side, just above and inboard of the top engine mount FW bolts. I'm yet to decide whether to use a separate third passthrough for my LSE EI wires.

 

[LettersFromFlyoverCountry]

I moved the fuel line very slightly inboard (there's another thread about this somewhere), partly to get a little more room from the contactors. One of the things that I wish Van's would do -- and maybe they already have -- is be a little more specific on the fuselage plans so one of the first things you're not doing is sticking in a doubler plate for the fuel pump for a carbureted airplane, without being more specific that this is not necessary for fuel injection. I had to work around that plate a few months ago when I made the penetration.

I also found the callout for the mixture cable to be not applicable in the configuration I have (TMX IO360, vertical ). I have a fixed pitch so i can't speak to the callout for that cable.

In the end, I haven't found any of the callouts to be show-stoppers.

 

[Sully]

I put the fuel line down low using the un-used fuel pump doubler for the supply and return line, just had to stay above the engine mount tubes

 

[Rupester]

After muttering about this for ...

...the last several months, and having read a TON of threads on this topic, my conclusion is Vans locations for throttle cable and prop control are pretty good. However, the "right" location for mixture cable penetration varies all over the map. You essentially have to have your engine hung and servo/carb mounted to know with any surety where the mixture cable penetration works best. After all my checking and reading, my mixture cable eyeball (where Vans shows it for FI) will NOT work. I now get to plug that 1.15" hole in my firewall there and drill another. Yuch.