Anytime you source out work to a shop, you are on their time schedule, not yours. You are not their only customer, you see, and with things being as crazy as they are with COVID interfering with just about everything, not all shops are operating at 100 percent capacity. But in my case, a two-week buffer was more than enough time. After just 10 days, my cage was complete and it was time to pick up the car!
If there were ever a time to make any fixes or adjustments, especially if the distance from your home to the shop is not close or convenient, the moment you pick up your project is the time to give the cage a complete inspection. It’s easy to “ooh” and “ahh” at the quality of work done, or be impressed with how they fitted the cage in the car. That’s going to happen regardless. The key point to telling you this is, make sure what you pick up from the shop will pass tech.
You already should have had a conversation with the cage builder as to the diameter and thickness of the tubing. Six-point? Eight-point? Twelve-point? How many connection points do you want? Gussets? Door bars? X bars? Know what you want or at the very least, have an idea of what you want. Most shops can recommend cage options to you if you aren’t sure, so don’t be afraid to ask.
I knew exactly what I wanted for this Spec E46 build. I spoke to the builder when I dropped it off. We discussed a simple six-point cage. I don’t feel a cage needs to be overbuilt, as I see so many cages done. I wanted some additional safety items included, so it ended up not really being a six-point cage, but a seven-point cage. I added a point in the driver’s footwell. In the event of a front impact, the wheel tends to get pushed into the footwell and, worst case scenario, it traps the driver’s feet under the pedals, or breaks feet, ankles and legs — all of which is bad. I want the driver to be able to exit the car after a crash, and I know this added structural piece will help to ensure that will happen.
The other option I wanted was NASCAR-style door bars for the driver. A common type of bar is a simple X bar that connects and triangulates the main hoop to the front A-pillar bar. The NASCAR-style bars use additional tubing, which is bent away from the driver seat into the pocket of the door. Above that bar is a second bar, which is connected to the lower bar with tubing in two or three places. In the event of a side impact, the NASCAR bars can better protect the driver by not allowing the driver side of the car to be pushed into the driver. It gives a buffer zone, or you could even say a crush zone if the bars were to bend in toward the driver — all to better protect the driver. It’s also a great level place to mount the lower part of the window net. As a bonus, it also makes it easier to get into and out of the car.
When inspecting the cage, don’t just look at the tubing itself. Get your hands on the cage to feel the welds at every point it’s welded where you can’t see it. This is exactly what every tech inspector will do when you take it to tech the first time. As per the CCR:
“15.6.13 Mounting Points
The roll cage shall be mounted to the floor area, which includes rocker panels, of the car in six, seven, or eight points. The cage shall not go through the firewall. The seventh and eighth points must attach to the firewall or front fender wells. All cage attachment points must be mounted to plates or a mounting box (plinth). Each required cage bar shall terminate on a plate with a 360-degree weld to the mounting plate, except as specified in Section 15.6.14.B. There shall be only one (1) mounting “point” per plate. This point is defined as where the “required tube” mounts. All additional tubes mounted to that plate must be mounted as close to the required tube.”
Some interesting words in there and for the most part, the NASA CCR covers the legality for all cage issues. That’s your bible on safety items. In some instances, class rules can outline additional cage requirements or give you “what’s allowed” guidelines, so it’s always best to read both before you begin.
My first point is it must be welded 360 degrees. That in itself is not always an easy task. If you were to build a cage on regular plates on the floor. Once you tacked it up, it would almost be impossible to achieve a 360-degree weld on the tops of the bars against the roof. Either you would have to remove the roof or cut a hole in the roof to gain access. Not really an option for me. Or with using plates, you could cut a hole in the floor so that the bottom of the main hoop and A-pillar tubes can drop down through the floor, finish welding 360 on the top of the cage, lift the cage back up and weld in the floor plates, covering up the holes.
My cage builder prefers using plinth boxes. They are more work than just using plates. Plinth boxes sit up above the floor plates and afford additional attachment points to the chassis. They are a 3D box. While in mockup, you tack the boxes in and continue to mock up the cage. When everything is all set, you knock the boxes out, which allows the cage to set down lower on the floor, giving you room to do final welding above. Then you just replace the plinth boxes and set the cage back on top. All that’s left is to weld in the plinth boxes. I prefer this route because of the added strength, and by not cutting holes in the floor, a potential corrosion point is eliminated.
What changed my mind from just using plates was seeing images of a Mustang laying on its roof with its cage footers being pushed through the floor poking straight up in the air and the roof completely flush with the beltline. That changed my view of using that method of building a cage, which I have done in the past. I don’t know any of the details on that particular build, but just “no” for me.
I was so happy with the cage because it was 80 percent how I envisioned it. That last 20 percent was better than I had imagined it. I remembered I had asked for a tab to be welded on the top of the driver’s side to mount a window net, and it wasn’t there. Better to realize it now than later. Being the great guy he is, he leapt into action and fabbed up a custom bracket for me and welded it in right there on the spot. I also noticed that he made and welded in a reinforcement plate for the rear shock towers and incorporated it into the rear cage mounts!
After staring at his excellent welds, he mentioned that I should get on the road before it starts raining. I laughed. It’s Southern California, in the mountains and it was early summer. We just don’t get rain at that time of the year. Well, I was wrong. After I left his shop there was a downpour as I wound my way down the mountain. I envisioned complete corrosion on the cage by the time I got it back into my garage. Perhaps it was the material he used or how he treated it, but, much to my surprise, there was minimal amount of surface rust on the cage. The worst part was actually up high at the top part of the cage. All superficial surface rust and it was easily dealt with by wiping it down with some rust dissolver.
Back in the garage there was still more work to do in the interior before it gets painted. For example, when the cage was welded in, everywhere under the car that saw heat from the TIG torch either burnt, scorched or melted the undercoating. These areas would begin to corrode and get worse if they were not treated. With a wire brush, I removed all of the dirt and loose bits in the areas affected. Then, using a putty knife, I scraped the rest of the bits off to allow for better penetration of new undercoating into the existing undercoating. I didn’t undercoat the whole car. Just the areas that were welded. It’s not pretty, but it is functional.
The next stop for the car will be to have the wiring harness completely gone through and some gauges and other components added, which will also be done at a shop because I’d rather muck a pig pen than do wiring. Yet another trip to a shop was in the works. So, in scheduling a time to drop it off, I learned I had a three-week window. Instead of just letting it sit for three weeks, I would tackle the rear subframe, bushings, differential, control arms, brake lines and fuel tank upgrades. All of it within that time frame.
