Firewall accessory mounting locations?

I'm just starting on my fuse kit on my -7A. The firewall is all match drilled and ready to rivet together according to the instructions, but after flipping through the plans there seem to be a number of items which could be easier to install now rather than after the firewall is part of the airframe. I'm hoping I can get input from those that've been here already whether the locations specified in Van's plans are correct for:

• Brake fluid reservoir
• Master relay and starter solenoid
• PC680 battery box

Although I'd also like to install these next items there seem to be too many variables at this time to determine a good location:

• Throttle / prop / mixture cables
• Heater box

I've also noticed in the drawings that the top portion of the firewall is bent at maybe 5 or 10 degrees to the rest of the firewall. Is it necessary or beneficial to put that bend in now before riveting all the stiffeners on?

Thanks,

Mike

Mike,
We are about the same place on the Fuse. After building my 6-A I am going to wait to drill or mount anything firewall forward. Things change, minds change, etc. and I would recommend waiting before drilling any other mounting holes, or installing the firewall recess unless you absolutely, positively know that what you are drilling and/or mounting will not interfere with something else down the line. There are a lot of mousetraps out there waiting to happen.

Just my $.02

I did a QB so the firewall was already riveted to the fuse when it arrived. It was easy doing the Brake Reservoir but had to drill out a rivet to mount the Master & Starter Relays. I would say just figure out which rivet that is and leave that rivet out. Same goes for the battery box.

FYI. Depending on what you use for firewall pass though's, the IMHO the fuel pump doubler plate should be larger. I used an eyeball fitting for my throttle and had to add some doubler material because the eyeball was half on the doubler,

If you are goint to use a gascolator, the gascolator doubler is much easier to install now from what everyone says.

You will have to order it as it does not come in the fuse kit.

It's easiest to nutplate for the contactors and battery box now per plans. They won't be in the way of anything later. Hold off on the reservoir; you may not even want it, and plans make it an obstruction to battery install/removal.

Don't rivet the recess until just before take-off. I suggest NOT riveting the floor/firewall/side skins until ALL fit-up is done ahead of the spar. Cleco as needed until then. Access is a beautiful thing.

If you don't already own a shop crane/engine hoist, do yourself a big favor and buy one. Watch auto parts ads; you can often find a 2-tonner for ~$160. Then, you can mount/dismount the engine when desired for access/fit-up/movement ease. Getting that slug of iron out of the way makes life much more pleasant FWF. You can hang it in 1/2 hour and remove in 15 minutes. Really. Don't cotter pin the engine mount bolts, yank it in five minutes, and lo and behold - there's a fully exposed firewall.

John Siebold
Boise, ID

Thanks!

Excellent info, guys!

Thanks for taking your time to respond to the post.

RV7ator said:

If you don't already own a shop crane/engine hoist, do yourself a big favor and buy one. Watch auto parts ads; you can often find a 2-tonner for ~$160. Then, you can mount/dismount the engine when desired for access/fit-up/movement ease. Getting that slug of iron out of the way makes life much more pleasant FWF. You can hang it in 1/2 hour and remove in 15 minutes. Really. Don't cotter pin the engine mount bolts, yank it in five minutes, and lo and behold - there's a fully exposed firewall.

John Siebold
Boise, ID

Click to expand...

Hey John, if it's that easy then I made a mistake by NOT asking for your help a couple months ago. Eric, another guy, and myself took over 2-1/2 hours getting that sucker bolted on!

So far, I've had 2 opportunities where having the engine off would've been easier, but for all that labor it wouldn't have been worth it. I just worked around the engine and got a few scratches on my hands.

Oh yeah, I'm still offering to be right-seat ballast if you need it!

A few more items!

Hey Mike, I'm about half way through hanging everything on my IO-360 and I wish I had looked a bit harder in the beginning. I would get a set of firewall foreword plans for your powerplant setup and give it a good look, there are quite a few bolts that wind up going through the firewall to mount: ground lug for engine, oil breather downtube, cabin heat cable bracket, manifold for oil-fuel psi sensors, to name a few.

Have a ball.

Steve

Get the drawings!

Mike,
I strongly second the vote to get the FWF drawings now. I waited, and had a more difficult time mounting the gascolator doubler. Also, I drilled the holes for the control cables early on, but wish I would have thought ahead a little. I would like to have used the eyeball pass-thrus, but a couple of the holes are too close together now. Not the end of the world , but a small annoyance. You can always delete the drawings from the FWF kit order if you use Van's FWF kit.
I still have to make a doubler for the AAH-OO-GAH horn (or a horn that plays the Nebraska fight song!). If I could just find a PMA'd horn :>)