'08 Hummer H3 Alpha build

  • Guest, You can choose a light or dark theme that works best for you with the "Style Chooser" botton at the very bottom left of this page!

JPaul

Rank IV
Member

Advocate II

Some shots showing the routing of the negative cable through the rear pillar. I'll be adding split loom along the length and some ABS pipe where it exits the pillar at the bottom to protect the cable. While it is the negative cable and does not pose a hazard if it wears through, it isn't good for the life of the cable.



 

JPaul

Rank IV
Member

Advocate II

I notched the lower and upper trim panels for the positive cable and the upper panel is notched for the ground cable as well. I had to do some additional notching for the positive cable due to a misjudgment on my part of how everything was going to fit. That subwoofer unit is really in the way and taking up a lot of useful space, but I also like the better sound I get with it, so it's a real toss up. Maybe someday I'll pull the subwoofer out and leave the Monsoon amplifier in place to use the space for something else, but for now I'll just work around it.





The positive cable is actually for a Kenworth tractor, it is 3/0 SAE SGX flex (though it doesn't flex near as much as the ground cable which is 2/0 marine cable with a more flexible jacket). I picked it up for a steal, especially considering the first item they sent me was some 2 gauge instead of 2/0 like the auction was originally labeled for but they let me keep in addition to sending me the "right" cable. However it was also 18' long, which was roughly 5-6 feet longer than I needed. Here is where having to rough fit everything first and then cutting the cable and crimping it outside of the car is a challenge, I may or may not have still ended up with it being too long. I won't know for sure until I get everything all put together. I am thinking though that I may cut the cable right where it curves around the subwoofer and make a junction to tie in another length of cable to use for powering a rear winch and/or providing house power to my trailer.

Tomorrow I hope to go get the material to start making the power center panel brackets and finish getting this closer to buttoned up.
 

JPaul

Rank IV
Member

Advocate II

Didn't get as much done as I was planning on today, instead I spent most of my time wandering around Lowes figuring out how to put the brackets all together and buying Christmas decorations for 75% off.

I did get the brackets in place tonight though. I used 1/8" x 1" aluminum angle and bolted it in place using the existing holes/slots the trim panel's clipped into.

Lower:




Upper:




Another shot of the upper showing the spacers (washers) to get it to fit correctly. Initially I used 1/2" nylon spacers, but those were too thick, then I tried 1/4", but that was still too thick, so I dropped down to 3 washers which is just about right.




The upper bracket is extremely sturdy, the lowering has some flex towards the rear but it should tighten up nicely once the panel is bolted into place. I'm debating if this will be strong enough to handle the dynamic load of my ham radio's main chassis, it's pretty heavy weighing in around 5 pounds. So even with how strong this should all be once it's fully assembled, I am worried about horizontal loading from the radio possibly eventually work hardening the lower rear sheet metal from flexing back and forth. I may just mount the radio chassis to the lower trim panel since it would be able to withstand the load just fine, but we'll see how it all works out. I am thinking of adding a brace from the rear-most bolt for the lower bracket to another bolt a few inches lower that the subwoofer assembly uses to help stiffen everything up, which would probably be a good idea no matter which way I go with mounting the radio chassis.

The next step is going to be measuring where the brackets are located in relation to the window glass, then putting the upper trim in place and marking where to drill, then drill pilot holes through the trim and the brackets. Then I will pull the trim back off, drill the trim to size for the mounting bolts, and then drill the brackets out to accept rivnuts and install those. I have a set of various sizes of metric rivnuts which will work great for this setup, I can simply bolt through the trim when installing the main panel for the electrical. I chose to go with metric for as much as possible on the H3 since virtually every bolt and nut on it is metric. It's a lot easier to only have to carry one set of tools to work on my rig, either at home or out in the field.
 
  • Like
Reactions: Jimmy P

JPaul

Rank IV
Member

Advocate II

Slow going thanks to the cold and just being tired from this entire year.

Managed to at least get the rivnuts in. Started out by measuring everything off the glass and marking the glass with a sharpie.



Next up was putting the trim back on, transferring my measurements and marking the drill locations, then drilling 1/8" pilot holes through the trim and the aluminum angle. I then drilled out the aluminum for the rivnuts. Since I am using metric rivnuts my standard drill bit sets didn't have the size I needed, so I ended up having to take some time running over to Harbor Freight and buying one of their 29 piece fractional sets.

For the installation I just used a M6 bolt, nut, and a piece of flat strapping that already had holes in it. It's a cheap and easy method for installing rivnuts without buying the tool that may or may not break on you unless you spend a couple hundred dollars. You simply hold the flat stock in place so that the rivnut doesn't try to spin, hold the bolt in place as well using a wrench, and then turn the nut with a wrench to set the rivnut.



I also added some red threadlocker to help secure the rivnuts. While they can hold in place pretty well usually, and in this case especially since it's able to bite into the aluminum nicely, you can run into instances where the rivnut may spin if it's over-tightened or the bolt seizes in it. Hopefully neither will happen in my case, but it doesn't hurt to be proactive.




I should have done some testing on the extra bit of aluminum angle to make sure the rivnuts would work the way I was anticipating, but I used a mirror to make sure they were flaring correctly. It's a bit hard to see here but if you look you can see the rivnut flaring out and biting into the aluminum.




Rivnuts all in place and ready for the electrical panel to be bolted in (once I fabricate it of course). This whole setup should be plenty strong and provide years of service.



 
  • Like
Reactions: Jimmy P

JPaul

Rank IV
Member

Advocate II

Finally got it mostly buttoned up today. It's complete enough that I was able to get the trim back on and the seats in so that my kids can ride with me again.

First up was making a chafing guard for the upper hole. I used some door edge trim that I cut to allow it to flex enough.




To make a sheath for the ground cable I took some heater hose, cut it in a spiral (so that it will stay on even with bends), and wrapped it around the cable. I ran into trouble feeding it back through the pillar as the heater hose kept getting caught and then trying to peel off. To fix that I used some of the adhesive heat shrink and used that to fasten the one end of the hose to the cable. Taking the subwoofer out to gain access to another hole in the pillar helped as well. I'm going to put some heatshrink on the upper end as well once I have everything all in place to make it clean.

 
  • Like
Reactions: Jimmy P

JPaul

Rank IV
Member

Advocate II

Next up was routing the positive cable. I gave myself several extra inches when I shortened it, since I know it's easier to shorten it again than it is to have to buy a whole other cable. Turned out to be a good thing as the extra length I gave myself ended up being just right once I had the cable properly routed and fastened into place.






And here it is with the trim back in place:




Now that this part is done, I am going to take my time to get the rest of it finished up. I still need to fabricate the panel that will go in the window, get that mounted as well as the fuseblock, run the cables up in the engine bay, and then start on the rest of the wiring for the fridge, radio, inverter, etc.
 
  • Like
Reactions: Jimmy P

JPaul

Rank IV
Member

Advocate II

Been a while, work has been keeping me busy and the weather has not really been cooperating when I do have free time, plus trying to get the house packed up and ready to sell has been chewing a lot of my time. I've made zero progress on the rear power of course, but with a trip to Moab coming up this weekend and then in May I'll be going to the Overland Expo West, I needed to get some work done.

To start, I am going to be putting some 20w (10w really, they're Chinese knockoffs of the KC Hilites, but still are just what I was wanting in a light as far as pattern went) flood lights on the roof as camp/area lights as part of this, but getting all the parts I needed for the switches and whatnot was not only going to take longer than I wanted, but I knew that getting it all hooked up would take forever as well. Fortunately my wife is very understanding and agreed that it would be best in the long run to just go with the Switch Pros SP-9100 instead of either trying to roll my own, or using some cheap Chinese knockoff that may or may not work well. Thankfully Amazon had it available with next day, so I received it yesterday and even better was the weather cooperating tonight and not raining on me like it originally was planned to.

First up was finally drilling the hole in the firewall for the boot I've had sitting around almost a year and getting that installed so that I could route the control panel cable in, as well as the cables for my oil pressure gauge. The gauge is still housed in the cardboard insert from the original packaging, but at least now the cables aren't being fed in through the door opening. Did I mention I've had very little free time the last year or so?



So that part didn't take me very long, maybe a half hour or so and that included trying to find my sealant. Next up was figuring out where and how to mount the control unit for the SP-9100. Since the warranty dictates that it has to be mounted upright instead of flat, I had to find somewhere to put it that permitted that orientation. Unfortunately the Hummer H3 is very, very short on space and surfaces in the engine bay, especially when it has a V8 shoehorned into it. I eventually figured out that I could mount it on the fender wall on the driver side. There happened to be an existing hole that I could put a bolt through after pulling the wheel well liner, and then the bracket would use that bolt plus an existing bolt used for a ground point after bending a "Z" in the bracket to space it correctly.



Here it is with the bracket and power unit all in place. This is as far as I was able to get tonight, but considering it originally was supposed to rain all day and night, I'm pretty happy to have gotten this much done. It took me a lot longer than I would have liked to get just this part mounted, but at least it's done right.




And while I had the wheel well liner removed, I took a shot to show why having a snorkel installed before the Moab trip is one of my (loftier) goals.



That is not several years of dust and dirt. That is less than a year's worth. I has moved the wheel liners over from my red H3 to this one since they were already cut for the Thor bumper. Considering we're just getting out of winter here, that is really only several months worth of grit built up in there. And to top it off I have done very little actual offroading with this truck so far. Most of it has been on the street.

While this is the driver's side, I am sure the passenger side where the engine air intake pulls from is just as dirty. So don't think that just because an intake is pulling from inside the wheel well that it's getting relatively clean air. There is still lots of dust getting kicked up in there while driving around, so for me having a snorkel (or raised air intake if you will) is a necessity to help my filter life while offroading, and just driving around in general.