Firewall grommet for muptial BIG wires

[theBroken]

Sorry for any misspellings and grammar error's, not my strong area by a long shot. Any mod's feel free to fix something if you feel it's necessary, I don't mind.

This is done on a American H3 with a auto trans. It cannot be done on a H3 with a manual or the South African H3's. I'm this can be done on many vehicles, just need to find the area for it.

I have the problem of having too many wires. I got 4~1/0ga. and 3~4ga that are getting changed to 2ga as soon as I save up some coin. I had a 1/0ga. and a 4ga. running through that big grommet on the fire wall by the hood latch cable and master cylinder. I got 2 amps, rear winch, rear battery, rear power inverter and a compressor in the back cargo area. I didn't want to run my wires through the frame or under the H3 in fear of them getting ripped off or damaged from weather. Plus my H3 goes offroading not just around the mall parking lot so keeping things secure is big on the list.

Here's my new firewall hole. It's a toilet drain for a RV toilet, the part that connects the toilet to the floor. And the the plug is a pipe cap for home plumbing for when you have to cut off a pipe that will not be used and need it capped. It's all rubber and the cap comes with a galvanized clamp on it. I think both cost 5$ or 6$ each. The cap came for ACE and the toilet thing came from General RV. It fits perfect.

I made the hole with a hole saw. I was worried about drilling through and hitting the ABS/master cylinder harness so I put a piece of wood between it and the firewall so when I went through I would see wood shavings and know to stop.

Heres some photos.

Tools needed: Ingersole-Rand's finest 2.25" hole saw.

The poop hole pass through and the pipe closure:

You can see one side is longer than the other, I kept the long side in the engine bay.

After you take the plastic off take the knee plate off. It will make the job much easier because most metal hole saws want you to run them at 300 or 200 RPM so it takes a long time to cut through.

Before

After

Silver sharpie to find the center.

My hi-tech way to find center, The hole on the engine bay side was for my spotter to see if I was centered when I went through. I was off just a hair so I went with it. You can't really tell when I was finished. I was more worried about hitting the ABS/master cylinder box. Call your dealership and see how much that thing cost and you will know why I was paranoid about it.

Inside before

Outside before

Heres the hole from far

Up close, fresh paint to ensure no rust

Here's just a example, I shoved a few wires through it, the end product will be much much cleaner. You can also see the existing grommet that I went trough.

From the inside. You can see the pinch welds and the studs for the clutch pedal if it had one. The pasty stuff is gasket goop. I filled the new toilet pipe in the gap with it and then I also spread it around the outside and inside of the firewall just to be safe. it's not just that you don't want water in it (of course) but you want to keep the atmosphere out of the hole you drilled. Even though you paint it and gasket goop it, it's just safe to add a little more protection just in case.

Outside in

[theBroken]

I filled the crevice on the toilet thingy with gasket goop all the way around it and all the way to the top. This is where the firewall will sit. Sorry for the fuzzy photo.

The final product. There's a few reasons I did this. 1 being I needed more space for wires. Another is I hate poking through grommets with wire looms in them. They make this special tool to do it with. It looks like a large solid metal pen. You put the wire in the hollow end and poke the sharp end through the grommet ensuring a very snug fit. I don't have this tool and I still don't like poking through the wire loom grommet. I think that's the dash harness too so mess that up and you will be having lots of fun. That's a guess BTW, I think it's the dash harness just because it has a lot of wires going from it to the dash. The other reason I did it this way and probably the best reason is that it's removable. Now later if I have to add wires or remove wires I just go buy another 5$ pipe cap and drill out new holes. Since it has that pipe clamp I can tighten it down and loosen it to remove it. I can set it on a table and drill out the exact holes I need and put gasket goop on it. I don't have to worry about hitting or cutting anything important either. Doing it this way just seemed to solve a few issues for me all at once so I thought I would share.

[Freshman6969]

thats a pretty cool idea, nice work too!

[bcpballer64]

Nice idea man i like it

[El1T3Bass]

Nice work man!

[Vilim12]

Did something similiar on my friends 94 F150, Behind the passenger seat there is a rubber disc about 3 inches wide all around and we ran the wire by his frame and drilled through the rubber disc. Came out looking great and cleaner than what I have in my own damn truck lol. Nice idea for sure