Minimize Firewall Openings for I/O 360

Starting building my "7" fuselage and want to only drill holes as necessary in the firewall and avoid re-work later (or unnecessary holes). I stumbled on the aux fuel pump doubler F-601Z not being needed for a FI engine and then discovered drawing OP-32 that shows a doubler for the high pressure fuel line through the firewall... Question what other "wish I knew" while building for I/O 360?

Appreciate all comments!

Why No Answers?

It always confounds me when I come across a great question like this and no responses in over a year.

SO maybe someone who has been through installing an IO-360 could help answer the OP question even though he may have moved on.

Question what other "wish I knew" while building for I/O 360?

Just me

I chose to wait on drilling the firewall until after engine was hung. I thought too many options to decide before that time.

I'll jump in on this one. I installed the doubler to reinforce the pass thru to prevent the thin SS firewall from cracking, and also the doubler provides enough thickness to allow you to properly tighten the retaining nut on the fitting.

Find a similar plane locally that you can view and ask the builder "What would you change if you were going to do it again?". Specifically in reference to wiring & hose penetrations on the firewall.
I have seen too many firewalls where 'symmetry' was deemed more important than 'workability & access'... unless you have small hands & bendable wrenches.

Ralph Inkster said:

Find a similar plane locally that you can view and ask the builder "What would you change if you were going to do it again?". Specifically in reference to wiring & hose penetrations on the firewall.
I have seen too many firewalls where 'symmetry' was deemed more important than 'workability & access'... unless you have small hands & bendable wrenches.

Click to expand...

Some of us don?t have a similar RV within many hundreds of miles and we rely on the answers we get here.

So anyone who can add to this great knowledge base, let?s here your tips !

I wish I hadn't put the fuel line doubler in the specified plans location - the hose nut ends up being very close to one of the firewall contactors. A half inch offset from the plans location would have been better.

Firewall penetration

I have an I0-360 but with a Catto fixed pitch prop.

The throttle cable hole location as per the plans is good and the mixture cable hole location per the plans is workable. On both these locations I used the Van's P/N: EYEBALL SE961-125S plus the 3M 2000 degree sealant.

I have run all my earth wires back to the firewall and I have used the BandC Aero ground block P/N: GB24 (i.e. 24 tab). They have a number of other combinations also available. This allows firewall penetration plus a common earthing point on both sides of the firewall.

For my electrical wiring I have used the firewall kits from Aircraft Spruce. They have three sizes which are 1/2" P/N: 09-02601, 3/4" P/N: 09-00978 and 1" P/N: 09-00979. The size you use and the location through the firewall will depend on the sizing of the wiring bundle and what components are being connected either side.

Before you start randomly drilling holes in the firewall work out where all the components are located (i.e. battery, contactors, etc) and make sure that components such as magnetos do not impinge on the wiring looms from where they exit the firewall.

Good luck with your building.

Here is how I located my firewall pass through's for the engine/prop control cables and electrical on my IO-320 powered RV-9A. It would work for any model RV.
I cut out a false firewall out of 1/2" plywood. The engine was hung from a shop crane/engine hoist with the engine mount attached and bolted to the plywood.
Now I had decided to replace the all the IP ribs and the sub panel because I was not happy with the previous builders work, so that was removed as an assembled unit and screwed to the aft side of the plywood firewall and scrapped later. You could just cleco new ones together for this step.
I then mounted the IP to it and the control cable mount. I had to compensate for the thicker 1/2" wood when I positioned the control cable mount. I was then able to start test fitting the control cables for routing through the wood firewall until I was happy with the outcome. I started by drilling the test holes at the per plans locations, but ended moving them as they were not correct for my application, especially the prop governor cable. No harm done drilling multiple pass through holes through a fake firewall. The pass through hole locations that I settled on were then measured and transferred to the SS firewall and drilled. I did not drill any electrical pass through's until the engine was permanently mounted and I was doing the wiring.