The construction projects and renovations are roughly half the battle; we also do no small amount of work directly for the team. When I started we did the usual voice/ data, fiber optic, wi-fi, and similar system cabling projects. Since then we have added cellular and emergency DAS systems along assuming responsibility for the broadcast system. I have additionally been named the Media Liaison and serve as a point man between the team and media partners. This role includes me and a few of my key folks working on game day media preparations and working directly on the sidelines during the games. When you see guys dressed all in blue during the games think of me… and the fact that a locost is not being worked on at all that weekend!
With the increase in work and the long term prospects of my new role my house is also up for sale. Buying a place with some serious garage space is high on the priority list… just not sure how long it will take to sell the house. It’s now been for sale 2 months.
We currently have a little lull between projects, so I’ve been able to make some progress. I’ve added the rear round tubes to the chassis, made the differential and transmission mounts, and have shortened the stock Miata driveshaft.
Shortening a driveshaft involves some risk; I decided I would order a custom driveshaft once the car is complete but wanted something I could use for fitment and low-speed testing. If and when I ever finish the car I will then sink the money into a custom driveshaft. My stocker has 189,000 miles on it and the u-joints are non-replaceable, so I didn’t see much point in paying a pro to shorten something that should probably be replaced anyway.
I started by taking a flapper disk to the driveshaft to strip the paint and surface rust off. I then wrapped a sheet of paper around it until it lined up and tape it in place. I used electrical tape (white was at hand) and wrapped it carefully around just short of the paper edge. After measuring 11.75" I repeated the process and then used a handheld bandsaw to cut closely to the tape edges. A bench top grinder was used to bring things right to the edge of the tape and bevel the edges for a cleaner weld.
Prior to cutting it's a good idea to lay a piece of angle iron along the shaft and scribe it with a straight reference line. Pay close attention to the orientation of the yokes on each end prior to cutting: you must keep these in the same alignment with each other or your universal joints will become universal binds!
For the next trick take a piece of angle iron and strap your drive shaft pieces into it so that your reference lines line up. If you're like me you can be in a hurry and forget about the reference lines for now. You'll have time later on after welding to remember why the reference line was there and you'll get twice the experience cutting the shaft and doing all this again (don't ask).
After tack welding the shaft in 4 places I laid a weld bead around the circumference and carefully ground it smooth.
The transmission and diff mounts are pretty basic and only need to give me a decent surface to mount to. I used 1/8” plate 4” wide and spanned some of the chassis structure. My motor retains the stock rubber mounts, so I also needed to use rubber mounts on the tranny and diff. In the locost spirit I used a hole saw to cut up a 1/2” rubber mat and then drilled the holes out a little larger. I have enough mat left over I could do my suspension arm bushings with the same material. I haven’t decided whether I want to go that low-cost yet. The extra money for polyurethane bushings would be well spent in the suspension.
You can see in the following picture the diff mount is pretty simple and will allow me to bolt the nose in place with rubber fusions above and below the diff. Looking forward in the tunnel the same idea is used to hold down the transmission. I am mounting the transmission from the old power plant frame bolt location versus using the less robust location near the tail shaft.
Bending the round tubes in the rear was accomplished with far too much thought and consideration of all the options. I decided to quit being a wuss and fabricated a rough jig on my build table. I welded the end of a 3/4” round tube shut, filled it with dry play sand, tapped and packed the sand in until full, and then welded the other end shut. I heated the area to be bent with a torch until really hot and then bent it around the jig. The results are certainly workable. In the process of making bends and cuts I made enough mistakes to make any professional cringe, but owning a welder and grinder allows one to cover a multitude of mistakes. I’m getting really good at welding sections of 3/4” round tubing back together and keeping the results straight.
If you bend the ends of the tube and end up with a twisted tube or the wrong length it is easily repaired...
The jig for bending is simple enough. I used a piece of oak board and cut out a 1.5" and 2.5" hole. The holes in the center were then drilled out out a little so I could put a 2" long 3/8" lag bolt through it, the MDF build table, and the 2x6 support. By grabbing the pipe on the right I was able to bend the pipe around the radius of the cut out.
The book drawings show the top hoop is bend on a 3" radius while the bottom corners are bent on 2" radii. My bends are little tighter than what the book calls for due to it being late while I did this. Radius, diameter... whatever. If you are following this build log with plans to build your own car I'd suggest cutting out 2.5" and 4.5" diameter holes. Then mount your backer board more firmly than mine (mine has a single pivot point and moves some). You will then force the tube to follow your radius more closely. I think mine are right on the money though it took a lot of sheer dumb luck- something I seem to have (and require) an abundance of.
I’ve only got a handful of tubes to weld in to complete the chassis complete with redesigned rear end for a Miata IRS suspension. My self proclaimed goal for this year is to finish the suspension and get this thing on its wheels. If I have steering done as well I’ll be very happy. We have some huge projects on the horizon at work so things could get crazy again soon.
