Roll Cage: Seat and Cage sides, final fit

Last weekend I’d decided that I needed to notch the transmission tunnel to make room for the seat.  So, today I got down to it.  I’d done some banging with the hammer before…and I’d noticed a squeal coming from the driveshaft the last time I rolled the car.  I was guessing that I mushed something over into the driveshaft.  Sure enough, I’d pushed the heat shield over…and the edge was rubbing against it.  I removed the heat shield and the catalytic converter.  I’ll figure out what to do after everything is back in place.


So, I used the angle grinder to cut two slits.  A little massaging with a hammer and the seat wings are about 1/4″ off the tunnel.


Installing the Cage side

I haven’t talked about the process of fitting the cage sides.  Its been tricky.  I wasn’t sure of exactly how the geometry was supposed to work.  The sides come left long, and you can’t exactly fit it into place to see how it is supposed to fit.  So, its hard to tell where to measure…and know how much (or NOT) to cut off each end.  it was a lot of trials…to avoid making any errors.  Anyway, I worked out a process once I figured out how it was supposed to fit.  I got to try it out on the passenger side.  So, here goes:

First, decide where the side is going to meet the top of the A-pillar.  This will determine how much to remove from the end that meet the footing.  then I measured the distance from the lower bend in the cage side to the footing.  I transferred this measurement to the side, and I cut HALF of it off.

That’s sort of my general rule as I’m assembling this thing.  Measure, mark, remove half…repeat.  As I get closer, it gets easier to measure in place, and make fine adjustments to off-angle cuts.


Anyway, once I got the footing within about 1/2” of what I thought would be final length, I switched and began to work on the joint with the main hoop.  I rotated the side until the footing was in place and resting against the inside of the main hoop.  Then I made makes on the end if the cage-side where it overlapped the main hoop…basically, marking the silhouette.

Then I also marked the point where the two bars touched.  This point is 90 degrees off from the axis of the fishmouth.  Next I measured the angle that the two bars meet…in this case I measured 5 degrees along the axis of the main hoop.

A key thing to keep in mind with Dave’s cage is that the knee bar passes between the dash and the heater core, under the steering column and then joins the cage side.  So, its important for the cage side to line up with this space.  There is some “slop” here, but you want to make sure before you finish all these cuts and don’t have any more margin.  Also, it is important for both cage sides to pass through the same area so that the knee bar can mount straight.  I used a short piece of tubing slipped under the dash to check alignment.


I removed the bar from the car, and first I moved the mark for the fishmouth axis 90 degrees around the tube.  I drew this line down the tube about 12 inches.  The line might not be right, but it gives me a reference line for adjusting as I inch up on the final cut.  Once I have the marks, I cut the end off about 1.5 inches long.  This leaves me plenty of room to test the fit, and make any adjustments to the angle of the fishmouth….again as I inch up on the final cuts.

Finally, I begin cutting about 1/8″ off each end at a time—testing the fit after each cut, and making any necessary adjustments.  It is a slow process…I spent several hours on each side bar.  Days really on the drivers side with the seat adjustments, and basic learning curve.  The passenger’s side took about 4 hours.


Once I was basically done….I wanted to leave a little more room to access the dead pedal…plus I wanted to spread any vertical load onto the rocker panel by joining the tube to it.  In order to make this cut, I used a spacer and a pencil to scribe the mark onto the tube.  Then I used the angle grinder to remove about half of it.  Then test fit, and as usual creep up on the final fit.  This may change the angle at the main hoop slightly, but it didn’t make a big difference in the fit for me.


Here’s the final view of the driver’s-side cage from outside the car, and with the seat in place.


After finishing the driver’s side, I went on to do the passenger side…ensuring alignment with the knee bar, as noted above.  This took the rest of the day.


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