In reply to wheelsmithy :
I agree, well, that is, I agreed...up until the moment when I started cutting metal last night...
HOW TO ENSHORTENIFY A MIATA RACK.
Having made my calculations, and with a Manhattan and a good dinner under my belt (and the kids asleep, or at at least in their rooms) I was ready to attack the rack. First, I fought with the little retaining clip that prevents the inner ball joint from unscrewing from the rack, and unscrewed the BJ. At this point I had a...well, we'll call it a moment. With the inner BJ out, I was able to peer down the inside of the rack and discovered that it was....hollow. And that the ID was larger than the thread of the Volvo tie rod end threads. So much for threading them into the Miata rack. Just going to have to take accurate measurements and proceed carefully to make the rack exactly the length I need it to be, and use the Miata inner tie rod end ball joints.
Using a pipe cutter, I cut the outer tube of the rack just inside of where it flares out to contain the end seal.
And then measure in 6-1/8" to cut off the length of outer tube needed to make the rack assembly the desired length.
Next, I popped out the rack seal on the flared end piece I cut out. When I go to weld the end piece back on, I don't want this burning up.
The rack itself was too hard and too thick to cut with the pipe cutter, but I was able to score it around its circumference to act as a guide for the angle grinder to make a straight cut. As straight as my hands could do it, anyway. First, off came the threaded end:
Then, another score with the pipe cutter 6-1/8" down the rack, and another cut. Don't forget to take into account the thickness of the cutting disc!
In order to align the two pieces perfectly, I went out in search of a piece of pipe or rod or something circular whose outer diameter would be equal to the inner diameter of the rack. This would hold the pieces coaxial during welding, and also add a bit of strength to the whole operation. In my stack of old Volvo parts, I found a cooling tube from an old B18 engine. The end was rusty and dented, so the tube was garbage, but it had a nice, clean, straight length in its middle that seemed promising. I cut it apart and, sure enough, it fit inside the Miata rack perfectly. For those curious, the OD of the tube was 5/8"
After adding a 45 degree chamfer to both ends of the rack, they were ready to go together. In goes the section of the B18 cooling pipe...
Together again, and it feels soooooo good.
Now for the part I was dreading- welding it back together. My first pass around the rack tube went pretty well- I had my Lincoln cranked up to 'D', the highest setting, and the wire feed low to push some heat into the work and make sure the weld stuck well. After a few more passes, grinding out little pits and abscesses in the weld, I ended up with something halfway-passable.
It was well past my usual bedtime at this point, but I was rocking and rolling and really wanted to at least get the rack welded back together. I ground-weld-repeat iterated a few more times after this picture, checking the OD of the rack and building it up a little here and there to make sure it was right. I'm reasonably content with the result- enough to start putting the rest of the rack back together. At this point, I need to weld on the end of the outer tube, and then put the inner tie rods ends back on. After that, I'll start figuring out how to mount the rack on the 1800ES, and work out the tie rod lengths and how to adapt on the Volvo ends.
Happy Friday!
