robbs70z Posted April 6, 2012 Share Posted April 6, 2012 (edited) Well I figured I should share this with the rest of you. I started to build my roll cage in my '70 240z a few days ago. I have already put new floors and frame rails in the car that I made up. I hoping that once the cage is done it will pass SCCA tech. I am building it to the rules I have read. If anyone sees something I missed please let me know. I started by playing the floor w/ .120 plate and then built 4"x4" boxes for the main hoop to be welded to. The cage is out of 1.5" .095 wall DOM tube. I am using a JD2 model 3 bender w/ a 180 degree 4.5" CLR die. It works really well and very accurate. All I have got done so far is the main hoop tie ends and the main hoop bent up and tacked into place. I have a few spots that are going to be a little tricky to weld do to how tight the roll cafe is going to be in the car. Hope all will enjoy and please let me know if you see anything wrong or that is missing so I can make sure this thing is spot on Enjoy!! Edited April 6, 2012 by robbs70z Quote Link to comment Share on other sites More sharing options...
johnc Posted April 6, 2012 Share Posted April 6, 2012 Make sure you weld 360 around every tube junction. We're now using bore scopes to inspect the welds in places that are hard to see. I generally have to drop the cage through the floor of the car to get a complete weld over the top at the main hoop, door hoops, and windshield bars. Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 6, 2012 Author Share Posted April 6, 2012 Diffentitly will. Thanks for the info Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted April 6, 2012 Share Posted April 6, 2012 What John said! When I did the cage for my corolla we hole sawed the floor to lower the tacked up cage into so we could get to the top. The floor/chassis mounts were the last thing made so that we could push the cage as close as possable to the roof. Cheers Douglas Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 7, 2012 Author Share Posted April 7, 2012 Unfortunatly I don't have that option. I will be cutting holes in the roof to fully weld the halo. Then welded the roof back up. Not something I want to do but already have the boxes that the roll cage ties into welded fully in. Quote Link to comment Share on other sites More sharing options...
johnc Posted April 7, 2012 Share Posted April 7, 2012 You'll probably be better off cutting the whole roof off the car then cutting holes. Its really hard to get the roof shape correct after a hole has been cut in it. Weld your entire roll cage into the car including the bottoms of the top welded junctions. Temporarily weld a bar inside the car across the C pillar below the factory seam. Cut the C pillar at the seam and near the bottom of the A pillar Use as thin a cutoff wheel or sawzall blade as possible. Clean up the seam area at the C pillar. There's tin solder and lead in the joint, don't want to weld that and definitely don't want to breath it when cleaning up. Weld the tops of your roll cage joints and then reinstall the roof welding 360 around the seams you cut. There's inner reinforcements in the C and A pillars that you won't be able to weld, but that's not a big deal since you've installed a cage. Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 7, 2012 Author Share Posted April 7, 2012 Thanks for the tip! Quote Link to comment Share on other sites More sharing options...
redneck1545 Posted April 8, 2012 Share Posted April 8, 2012 I did what 74_5.0L did and only tacked my cage in place while I measured and cut all the additional supports to the rear main down braces. I 'should' have left a little more room on one of my braces for it to be easier to weld up but hindsight is always 20/20 right. Regardless, it now has a bead all the way around, just not as pretty as the TIG welding on all the other joints. I just made the whole rear half of the cage, tacked into place and rolled it out when I was ready to weld all the joints. Fit like a glove. The shop that did the tig welding for me asked where I wanted the main hoop placed in relation to the map light bar and as they were rolling it back in place they said " well dang this thing just kinda locates itself doesn't it, is that where you want it?" I took a quick look inside and it was exactly the same place where I tacked everything up at!!! I said sure is, weld away Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 8, 2012 Author Share Posted April 8, 2012 So I am off this week so keep posted will be getting the cage hopefully done this week. Also a question on the halo hoop/ hoop that comes off the main hoop and wraps around the roof line. Does the 180 degree rule apply to this as well or can I follow the contour of the roof? Thanks for all the imput. Quote Link to comment Share on other sites More sharing options...
johnc Posted April 9, 2012 Share Posted April 9, 2012 Halo bars do not have a 180 degree bend limit but must have the arms extending back to the main hoop horizontal. a. Closed carsGCR - 109 9. Cars and Equipment General The front hoop (side hoop) must follow the line of the A-pillars to the top of the windshield and be connected by horizontal bars to the top of the main hoop on each side (as close to the roof as possible). Instead of a single front hoop, two side hoops (down tubes) may be used. Alternatively, a top “halo†hoop following the roof line from the main hoop to the windshield with forward down tubes following the A-pillars to the floor may be used. Regardless of which one of the two approved tubing configurations there shall be a tube connecting the two A-pillar tubes at the top of the windshield. b. Open cars The height of the front hoop (per section 9.4.B.1. must be consistent across the full width of the cockpit. c. Front Hoop Bracing All open cars with a high front hoop and all closed cars except those competing in the Improved Touring, Showroom Stock, and Spec Miata classes must incorporate a horizontal front hoop brace at the approximate level of the dashboard. It is recommended that cars competing in Improved Touring, Showroom Stock, and Spec Miata classes also have the front hoop brace. Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 9, 2012 Author Share Posted April 9, 2012 Awesome!!! Thanks John when reading that SCCA book my eyes start to wonder. So much info. I am doing the a pilar bars that follow the roof line to the main hoop. A little more challenging do to how picky I am Pics will soon to follow later tonight. In the process of playing the rear strut towers and doing the a pilar tie ends since I didn't offset one of my bends to follow the roof line correctly. I will post I pic of the oops as well later. Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 10, 2012 Author Share Posted April 10, 2012 (edited) Alright so here are a couple pics of the plateing of the a pilar tie ends still need to do boxes for them. Also cleaned up the rest of the interior of the car aka wire wheeled it. Also plated the rear strut towers. Also does anyone know if I can weld the roof to the main hoop? Here are the those pics plus the pics of the oops a pilar bar. The black mark in the middle of the bend is where the tube is supposed to go. Bending up new a pilar bars tonight w/ the correct offset. Edited April 10, 2012 by robbs70z Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 10, 2012 Author Share Posted April 10, 2012 Got the A Pilar tie ends done tonight The kid didn't want to go the sleep so didn't get as much done as I like. Enjoy Quote Link to comment Share on other sites More sharing options...
sq_creations Posted April 10, 2012 Share Posted April 10, 2012 Very nice so far. I like all the re-enforcement plates! Quote Link to comment Share on other sites More sharing options...
johnc Posted April 10, 2012 Share Posted April 10, 2012 Well, you're not doing a Halo bar, you're doing regular door hoops. Again, no 90 degree bend limit stated but its best to have the bar coming up off the floor as vertical as possible and the rules do require the part of the hoop going back to the main hoop be horizontal, so in practice you do have a 90 degree bend limit when door the bar is viewed from the side. If you're going to run the stock dash, steering column, and pedal box, start thinking about the dash bar and the two braces going forward to the fire wall. How are you going to fit those, what order to fit them, and how are you going to weld 360 around them? Leave room for welding access in your design. Quote Link to comment Share on other sites More sharing options...
johnc Posted April 10, 2012 Share Posted April 10, 2012 Also does anyone know if I can weld the roof to the main hoop? It depends on what class you intent to race in. IMHO, its probably not worth the effort. I've done it in the past for a roll bar but really didn't notice a big difference. With a full cage it is probably just extra work. Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 11, 2012 Author Share Posted April 11, 2012 Thanks for the info John. Quote Link to comment Share on other sites More sharing options...
robbs70z Posted April 11, 2012 Author Share Posted April 11, 2012 (edited) Tonight got the drivers Door Hoop in and tacked into place. Left just enough room to weld it into place. Would of done it earlier but had to trim some sheet metal back to get it to fit where I wanted it. Enjoy Edited April 11, 2012 by robbs70z Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted April 11, 2012 Share Posted April 11, 2012 Looking great! I wish you were my nextdoor neighbor. I'd bring in your paper everyday and take your trash can down for a year if you'd build me a cage that nice. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted April 11, 2012 Share Posted April 11, 2012 Looking great! I wish you were my nextdoor neighbor. I'd bring in your paper everyday and take your trash can down for a year if you'd build me a cage that nice. No kidding, me too! Masterful fitment! Quote Link to comment Share on other sites More sharing options...
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