Clean way to route wires through firewall?

[JMD]

Hey all,
I'm in the process of wiring my k10 build. I have an American autowire kit which unfortunately doesn't come with the square plug for the firewall. I know not everybody uses that plug, but what are you using? The firewall is already painted so I don't want to weld in a patch, what are my other options? Pics would be extremely helpful.
Thanks, Jordan

[In The Ten Ring]

There is already a way through the firewall.

The original windshield washer pump has three rubber tubes passing through a grommet. Most people have (or will) replace their washer pump with something more modern under the hood. That leaves that same grommet as a gateway through the firewall.

This is the route I'm going to use to mount my forward cam, fog lights, and laser pointer.

Why a laser pointer? To aim my truck's forward cannon and machine guns, what else?

*The plan is to use a laser pointer to help align the truck to go through my ultra slim garage door.

[JMD]

I can do that, but then what do I do about the giant square hole in the firewall?

[In The Ten Ring]

Why do you have a "giant square hole in your firewall?" Were you hit by a giant square bullet? LOL

Just kidding. I assume you are doing some custom work....but why the large square hole in your firewall?

[Dustytrix]

Originally Posted by JMD

I can do that, but then what do I do about the giant square hole in the firewall?

You could cut a plate and bolt it to cover the old plug hole. That is what I am planning anyway.

[SactoJim]

Hey JMD......I saw your private message.....not on the site as much as I used to be. I used this type of grommet for mine. I had to fab a square stainless flat piece to cover existing hole because the grommet itself was not big enough. They make them no split as well but I used split when i redid my fire wall because I had to.

http://www.jegs.com/i/JEGS/555/60777...43saAmBK8P8HAQ

[Overdriven]

Get a nice piece of 18ga stainless steel large enough to cover the hole. If you can access under the dash weld a pair of studs to the backside of the stainless so it's nice and clean on the front. Drill the appropriate size hole in the stainless for a grommet to pass the wires through. Polish the stainless or paint if you prefer, make a gasket or glob some sealer on the back of it and mount. Hole filled and wires run through stock location for no issues with the harness.

[In The Ten Ring]

Originally Posted by Overdriven

Get a nice piece of 18ga stainless steel large enough to cover the hole. If you can access under the dash weld a pair of studs to the backside of the stainless so it's nice and clean on the front. Drill the appropriate size hole in the stainless for a grommet to pass the wires through. Polish the stainless or paint if you prefer, make a gasket or glob some sealer on the back of it and mount. Hole filled and wires run through stock location for no issues with the harness.

I'm not welder, but I took a couple of welding classes. Doesn't welding stainless require some steps and safety processes mild steel doesn't?

[JMD]

Originally Posted by SactoJim

Hey JMD......I saw your private message.....not on the site as much as I used to be. I used this type of grommet for mine. I had to fab a square stainless flat piece to cover existing hole because the grommet itself was not big enough. They make them no split as well but I used split when i redid my fire wall because I had to.

Thanks for getting back to me, I figured you had to fab some sort of backing plate up. I don't possess the skills or the tools to weld stainless or do any sort of real fabrication...I just found those square tubing caps that I think will work quite nicely.

http://m.ebay.com/itm/2-1-2-Square-T...-/141632511604

The square is 2.25"x2.25" so I'm thinking a 2.5" cap will fit even if I have to shave it down a bit. The site says that the cap will fit in a 2.25"-2.42" hole so I can't see why it wouldn't work...And for $2.75 why not right?

[Overdriven]

Originally Posted by JMD

Thanks for getting back to me, I figured you had to fab some sort of backing plate up. I don't possess the skills or the tools to weld stainless or do any sort of real fabrication...I just found those square tubing caps that I think will work quite nicely.

http://m.ebay.com/itm/2-1-2-Square-T...-/141632511604

The square is 2.25"x2.25" so I'm thinking a 2.5" cap will fit even if I have to shave it down a bit. The site says that the cap will fit in a 2.25"-2.42" hole so I can't see why it wouldn't work...And for $2.75 why not right?

That looks perfect, good find.

Originally Posted by In The Ten Ring

I'm not welder, but I took a couple of welding classes. Doesn't welding stainless require some steps and safety processes mild steel doesn't?

I'm just a self taught hobby welder (MIG only so far) who picks the brains of more knowledgable folk when I can. I've never seen anything about safety issues with stainless, but there are many different types of stainless depending on the alloys used in them so it's possible you need to be careful with some of them. Google the alloy you're working with to find its requirements. You do need special wire, some settings need adjusting and higher inert gas content (90% or more helium or argon) is recommended for most stainless alloys. The settings and shielding gas are all related to the thermal properties of stainless to get good penetration, controlable puddle and proper cool down time. The couple times I welded stainless sheet metal I didn't change my shielding gas, just put in the proper wire, adjusted my settings and technique a little and had good results.

Only reason I recommended stainless here was that it could be polished to avoid paint matching or if painting it basic black was unacceptable. Plus the backside wouldn't be seen so the welds wouldn't have to be pretty.

[JMD]

Just a quick update, my tube caps showed up in the mail and fit perfectly. If only everything else with this build was such an easy fix...