I'm just wondering how big ( or small ) a panel should be to mount a fuse box and other electrical components on the inside of the firewall of my 26 RPU. I have an American Autowire Hwy 15 kit and know the size of the fuse box, just wondering what other things I may end up having to mount with or near it. That would affect the size of the panel I need to make, keeping in mind there isn't a pile of room on the inside of a T firewall to begin with Another issue is that I didn't weld any type of mounts for a panel into the inside of the firewall and I really don't want to drill holes to mount one in my nicely finished firewall I know some guys have used magnets ? Or maybe some sort of panel adhesive would work ? I want it to be spaced out slightly from the inside of the firewall to allow for fastener hardware clearance things like rivnuts etc. Any ideas or pictures of what you have seen or done ?
RTV Silicone is often used to mount things that cannot be bolted, but still might have to be removed at some point. you don't need to go overboard. Once it sets up good, 4 corner spots will hold it solid, and you'll be glad you only did 4 spots if you are forced to change it's location later. I would not use magnets as I've slammed some deep potholes and curbs by accident, that would likely cause it to drop and maybe screw up your day.... but good. Panel adhesive eventually sets up too brittle for me.. and it might not let you pop the board off without breaking it, if you ever needed to. One tip I learned on hamb...paint under the dash area in white. It sure makes a huge difference after the car is done, in case you need to look up in there. I did that on mine. .
I installed two panels (aluminum with hammer-tone paint) to which I mounted components.One on drivers side has fuse block and places for additional grounds (doesn't look like it in the photo, but the paint was off under the bolts/screws for clean grounds). One on passenger side is for a terminal block with dash wiring going to it and a space for the mini-stereo amp I installed later (pic of amp,but not installed.....hooks to a hidden 3.5 jack for Phone/Sirius/Pandora to plug into) The dash gauge wiring was done on the bench for easy wiring and the wiring hooks to the terminal strip (color coded wiring) so if I needed to later, I could disconnect the dash harness and just remove the dash. By splitting in two panels, they were easier to mount. As you can see, there is square tubing for body structure that I fastened the panels to.You could maybe panel adhesive these in place, and screw the aluminum panels to the square tubing. Also, I know the split looms and zip ties are not traditional, but they do work!!!LOL
Yes You will thank yourself later! My roadster has pretty basic electrical needs so the actual fuse panel is very small, I made the mounting panel bigger than I needed for future add-ons, glad I did as I decided to mount the MSD box on it. I used a large bakelite coated wing screw for quick servicing. The small black unit in the lower right is a master fuse. There are a few specialty automotive wiring suppliers on the internet that carry some handy components like the master fuse and junction/ground pods, but its been quite a while and I forget their names.
I've used some special purpose Velcro with great results. They make it in heavy duty version that I use on the kids 60 mph r/c cars. Sent from my LG-LS993 using The H.A.M.B. mobile app
Run a ground to your mounting bracket, and any others you use. Don’t count on the body panels for grounding. A couple grounding bars here and there can save a ton of trouble shooting later, especially if it’s old original body panels.
Here a panel I made. I used original firewall holes to mount it. Spaced it back so I could insulate behind it. I also welded bolt to the chassis before I painted it. I used this as a star point ground for the starter, battery, a 10 gauge ground to an aluminum block under the dash. A little overkill but that how I usually think.......
I thought ahead and welded a bracket to the dash that my fold down fuse panel bolts to. That aint a hell of a lot of help now but I suppose panel adhesive, the good stuff that auto body shops use, would work. I sure appreciate the fold down feature, handy when you have to work on it, invisible the rest of the time. Make sure you make the panel large enough to hold the fuse panel and all of the relays you are using. You sure are building a nice RPU!
I second the Velcro suggestion made by Hyvolt. Holds tight, but removable when needed. If still looking for other ideas, you could also use a good quality 2 sided tape like bodyshops use for reinstalling bodyside mlds, or if you want it pretty much permanent use windshield urethane.
I used a Painless wireing kit. I built a simple mounting bracket to hold everything so that it can be easily unbolted. The round spacers allow for Dynamat and carpet to slip behind. Tapped spacers glued to your firewall would allow you to unbolt everything as a unit.
I have a few relays from a '90 {I think} buick on mine, which is an aluminum louvered panel that swings down from under the passenger side of my coupe.
Lay out your components in a mock up of spacing, where wires will need to be routed, then construct.a box that uses the measurements. Thin qauge steel, or aluminum suitable for bending. Make allowances for covered switches. These should be on the bottom of the box. Add nutserts to the firewall that extend throu vacant spots inside box. Paint box crackle black or brown. Inside and out. Install parts and wires, switches and bolt to firewall. Pull wires and attach at preselected location and add to circuits. Test and test drive.
I have successfully used panel adhesive to locate a heater and don't see any reason it would not work on an electrical panel mount. I would put a square tubing of sufficient depth to space the hinge away from the firewall enough to clear your insulation package and install a hinged panel as others have suggested. Below are a few pictures of my installation in a 40 ford. It is probably more complicated than you need but you may glean some ideas from the pictures that are useful in your planning process. I am sure you will come up with a good plan for this as you have done foe other systems throughout the excellent build of your RP.
That is an excellent idea using the 6 dash pod mounting bolts, and not making any more holes in the firewall.
How about mounting your electrical panel off the two straps that run front to back beside the cowl vent that supported the original gas tank? No new holes need appear on the firewall.
Think of all the fused circuits you need, then add 2 or 3 empty fuse positions for those things you didn't think you would ever need. A spare relay socket doesn't hurt too. Don't forget your indicator flash unit , this can be mounted on the panel too. You can put a brass 3/16" screw on the panel, and use this as your earth point.
I ended up putting longer bolts from two of the radiator support rod brackets and one of the bolts for my transmission dipstick. That left one bolt to add through the firewall on the drivers side down low. That gave me 4 mounting points with 1/4” bolts. So, I made up an aluminum panel that’s spaced out from the firewall about 1/2” on small feet. Should work out good I’ll paint it white once I get the wiring all laid out.
I used a drop fold panel from a 90's Ford Taurus. Mounted on pass. side, away from traffic. All you could see was the "pull" handle.
I did modern it up some with a small panel mounted on the cowl seam. Location for the flasher, horn relay, ignition relay, and relays for the vintage three wire signal switch. The ballast and coil is powered directly off the ignition switch and the relay supplies juice to the wiper, heater fan, choke heater, etc. I used relays for directionals instead of a trailer converter out of personal preference. ..and I did secure the ground wire with a nut.