My Cobra Build Site

Another pretty productive weekend with lots of different activities. It’s hard to concentrate on one particular area of the car as there’s always one thing that needs to be done while you work on other stuff.

Most of the waiting time is for paint-related items. Lots of spray paint flying around the shop right now as I paint all of the aluminum panels for the engine bay, the rear end parts we’ve been working on, and the brake booster setup.

More detailed info:

Rear End:

I made the decision that for autocross (which I’ll be doing in this car), the 4-link suspension setup was going to be wholly inadequate. That means I need to upgrade it to a 3-link setup, which uses the original 4-link as the base. Fortunately, FFR sells a retrofit kit that includes the panhard bar, cross members, braces, and all necessary hardware. All in all, the upgrade is reasonable at $550. Considering the 5-link is $1700, this isn’t a bad option. This is going to be my birthday present this year (and probably most of Christmas!

Since the original 4-link was going in, the lower control arms are designed for it, and have brackets and perches we don’t need. We decided to be both anal and brave at the same time, and we broke out the grinder and get rid of the extra stuff. Michelle made quick work of it as a start, and I finished up the first one. We also cut off the quad-shock mounts from the axle housing and drilled holes for dv/dt’s possible bracing mode using the upper ‘ears’ on the axle.

Unfortunately, I also finished up my cheap grinder. A combination of using the wrong wheel, and not cooling it adequately…I let out the magic smoke.

Pics:

Driver’s Side Footbox, Brake Booster, Pedal Box, Engine Bay Aluminum:

This is a multiple-personality set of projects. I’m putting the footbox together, putting the master cylinder and brake booster together, and putting the pedal box together as well.

Everything has to be painted before going in. I’m using Hammertone on the panels, and although it looks nice, I’m not that happy with how it all goes on. It does not touch up well as it more or less has engineer “orange peel” so you get high and low spots as you try to touch it up.

Other parts like the brake booster and pedal box are getting just a metallic aluminum paint, and I like it much better.

Brakes:

I decided after driving Mike’s non-powered brake car, I definitely wanted to go with the boosted system. Whitby Motors puts all of the necessary parts together for you, and the kit is top notch. Since you have to cut the frame to make room for the big booster (the car is designed for manual brakes), they even include a well-designed frame brace to make it possible. If you want power brakes, this is the way to go.

You do have to make room in the footbox metal to get the booster’s boot and push rod assembly through. This was a bit of a challenge for me, and I ended up kind of hacking it up a bit, using my sawzall. If I had it to do over again, I would have bolted in a piece of wood or metal as a backing, and simply used a large holesaw instead. You need the backing so you have something to guide the holesaw.

You also need to move the steering shaft bracket to the inside of the firewall. Despite the spacers, the booster will still hit. This is a very easy movement though, so not a big deal.

A bit of bad news, as I assembled the pieces, I discovered the booster is broken. The good news is as I was doing this entry, Jeff got back to me. I’m shipping him the booster and he’s replacing it. He’s a good guy!

Pics:

Bench Bleeding – since I hadn’t done this before, I had to look it up. A lot of guys say it’s more trouble than it’s worth, but after doing it, I can see the value. This includes filling the reservoirs, hooking up the tubing, and then actuating the push rod piston manually until you get all of the air out (AIR IN YOUR BRAKES = BAD.) The basic procedure is to clamp the master cylinder in a vise, get it totally level so the bubbles will come out, and then push the piston in and out until it gets the air out (this primes the system). This is easier said than done. I ended up removing the plugs one at a time, and mounting the resevoirs to a board high above the bench. I used 2 3/8″ socket extensions to push the piston in. You’ll start with more than 1″ of travel, and eventually when it’s primed, you’ll get less than 1/8″. It took me maybe 100 strokes to get it there. Much better than doing it with the pedal and pushing air through the whole system.

Engine Bay Aluminum – This was a pain. The guy I bought it from was not going to paint his stuff, so the f-panels and firewall have all already been sealed and riveted into position. I’m doing all hammertone as mentioned already, so in order to paint what’s there, I could either drill out and remove the panels, or tape and mask around them. The 2nd was the lessor of 2 evils, but it took forever, and was a pain. The good news is that the frame (powered coated) cleans up easily with goof off (lots of over spray, despite my efforts).

If you want to see what white engine bay panels look like, see the in progress pics, the primer I’m using is white.

Pics:

Pedal Box and Pedals – I put in Russ Thompson’s go-pedal and brake and clutch pedal covers, which required a lot of cutting of the stock mustang pedals, but it came out nice. The throttle pedal is aluminum, so you have 2 options for paint (if you want them to match), either paint that one black, or paint the other 2 aluminum. I chose the latter. I’m not sure if I’ll keep it that way, it might be too much contrast on the back carpet, but I’ll give it a dry. It’s easy to brush on the black latter.

The main issue I’m facing now is my size 11 feet. The pedals are pretty close together like a race car, which isn’t a big deal, but the gas pedal is only about 1″ from the side wall panel. Greg M did a nice bump out to give him more room, and I’m waiting on measurements to do the same thing. Hopefully, that’ll give me the room I need.

Pics:

Next Up:

I’ll wait for the new booster to show up, and work on the bump out on the DS box. I’m also going to mount the steering shaft in place so the booster will go in and stay there. I also need to figure out where to mount the reservoirs (probably on the firewall) and get the hole drilled out for the heater (actually need to modify the one that’s I did already for the ffr heater…I switched to a summit one instead.) So…big fun and continuing on…

Alright, before you even think it, I KNOW this isn’t the prettiest foot box in the world! ;-> I’ve deemed it the patchwork-quilt foot box mod. However, I did this knowingly and more or less on purpose.

Why aesthetics don’t matter in this case: I’m going to be adding heat-insulating material over both foot boxes and the firewall, so when it’s all buttoned up, you’ll never see the patches. With that in mind, it didn’t make sense to spend the extra money on aluminum making 4 new panels. My 2 main concerns were that it was bigger, and that it was structurally sound. Mission accomplished on both areas.

All in all, I’m pretty happy with the way it turned out, especially considering I’ve never fabricated with aluminum before and I had to use a DIY bending brake setup to make a 4-bend box for the end piece.

Cost – about $20 worth of aluminum panels, same grade as FFR kit.

Thanks – to Ray for the initial pics of 4 into 4 headers so I could gauge if everything would clear. I feel pretty good that I’m good to go there.

Procedure:

Background/Step 1 – My situation was a little different because the kit I bought was already started, and the foot box was already assembled. That required me to drill out all of the rivets and cut through and wire wheel the black sealant off of the box. Not a big deal, the wire wheel in a drill does pretty quick work of that stuff, although it makes a huge mess.

Step 2 – After everything was cleaned up, I took my tin snips and cut the fold on the inner wall of the foot box so I could create an angled bend. I did so in a place that would ensure the largest header bend would still clear. I also bent out the original panel ends to make straight pieces out of them.

Step 3 – After measuring everything, I made a new bottom panel by using the original as a template and adding the new lengths that I needed. I originally used snips to cut the aluminum, but it makes a jagged mess of the panels, so I switched over to the jigsaw with a metal blade. It’s kind of difficult to get a true straight cut with a jigsaw, but it did the job well, and cut quickly.

Step 4 – I put the top panel back in place and made a “patch” to fill the gap created by the new inner panel bend. I was worried it wouldn’t be strong, but it actually turned out great.

Step 5 – The fun part…I wanted to basically make a “cap” that would fit over the other 4 panels on the end, so I had to create a sort of box as the end panel. The top 3 panel bends fit inside the others, and the bottom is under the bottom panel. This was pretty challenging, especially bending since my bending brake was basically a piece of angle aluminum and a board and rubber mallet. The most challenging part was getting the piece in place though with the 3/4″ down sloping tube and the large round 2″ tube in the foot box. Took some moving around, but it went in. I did scratch up the powder coat, so a little touch up was needed.

Step 6 – The end panel left a gap of about 3″ from just under the 3/4″ down sloping tube all the way around and down. I cut 2 separate pieces to fill this gap and it all worked pretty well.

Step 7 – Rivet everything in place – this hasn’t been done yet, but will be soon. It’s just screwed together right now, and it’s pretty darn tight.

I had my wife test it and I took a pic of my legs in there. I’m 6′ and size 11 shoes.

I took some pictures of the measurements, however, since every installation is likely to be different, your mileage may vary. If needed, I can take some better measurements of what I did.

Pics:

Passenger Side Box