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Wiring thru the Firewall...Thoughts on how to do that??

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  • Wiring thru the Firewall...Thoughts on how to do that??

    I've seen several beautiful arrangements in threads but now I'm in the reality phase of going thru or around my firewall. My Power Brake unit is over where the original wiring went thru and all the 60 year old wire is being replaced, so now is the time to get it right. Rubber plugs are available but nothing seems to "fit" a bundle of 8-10 wires. Location of the fuse panel and relays is probably under the dash.
    Any ideas or leads to products that would work will be appreciated.

  • #2
    What kind of wire sizes are you running? How fancy do you want to be? There are bulkhead connectors in various systems like the weatherpac connectors I used, but they are limited in amperage and require some special tools and do not look factory.

    Alex J. is using some military based connectors. They will probably look more appropriate but have similar issues as the weatherpac connectors.

    I did once find some very nice rubber boots for running wires/cables/hoses through firewalls, they had a nice boot that could be zip tied to the bundle to seal nice and tight. Some searching should turn them up again.

    I used a weatherpac bulkhead connector for the smaller stuff and ran the large feed wires through a bulkhead grommet I sealed with some putty and then terminated those wires to a terminal block panel on the firewall.


    • #3
      Guess I should have elaborated...

      The 1957 OEM wire was 16-18 Ga. with a few 12 and 14 for heavy load circuits. I have Wire Barn 14 ga in 11 colors for simplicity with a wire for a few circuits in heavier ga. The quantity of wires is maybe 10-14 so the 22 wire cannon plug is overkill but (according to Summits listing) will support 18 to 12 gauge wire. So, I have been leaning toward that since it is only about 3" diameter.
      I've looked at both Weatherpack, Am-Autowire and a bunch of others.
      This build is basic so there isn't a computer on board and would prefer easily available connectors.
      I'm sorting an order for the Grommets on Am-Autowire page 100 to run wires thru where there isn't a bunch of wires needed like speakers into a door.
      Just thought I'd ask the question and see what opinions pro and con I got.


      • #4
        The weatherpac connectors will support larger wire diameters but are not rated for heavy continuous amperage loads. The pins aren't big enough. I don't remember what the limit is, 20 or so amps I think. Most stuff is probably fine but headlights are probably about the limit for what they should be used for.

        I'd probably just use grommets then. If you want the ability to easily disconnect wires then a terminal block or two on the outside of the firewall would look suitably old-school and be a simple but effective option.


        • #5
          Originally posted by Desoto61 View Post

          Alex J. is using some military based connectors. They will probably look more appropriate but have similar issues as the weatherpac connectors.
          The 37 pin Amphenol shell I used is only rated for 13A per pin. I know a lot of guys who will braid 2 or three wires in the connector to act as a heavier amperage load (still nobody I know pulls more than 30A on a three wire braid) but these connectors are kinda pricey. However, they do fit the Heavy Duty look of our trucks. sells some all black series ones that are cheaper than the actual Amphenol ones.

          For other smaller connections I am running the Deutsch series connectors, primarily because that is what is already on my ISB Cummins. These are also pretty cheap and super easy to assemble. I'm in the wiring phase of my build now and I also bought the 11 color wire kit from wire barn! It is really nice wire and I like that in the future I can buy each color by the foot. This stuff is as nice as the wires that came in my CAN system that I am using. Aside from two or three sender wires, and 2 CAN signal wires, the majority of the wires in my bulkhead are just low amperage check engine / wait to start lights from the Cummins, and the cluster of wires to my fly-by wire throttle pedal. The other thing I am making sure to do is keep track of all my connections on a spreadsheet, and labeling everything and at which connector it goes to that way later down the road either myself (or someone else depending on my health) can actually work on this thing. The 37 pin connector was certainly overkill but as I go along I am leaving some extra points to add other things later one. Can't think of what, but ya never know!

          1942 WC53 Carryall in progress.