Jump to content
HybridZ

Series 1 240z Roll Cage Build


Recommended Posts

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!!

 

f12cd273.jpg

 

b62d3846.jpg

 

98b82c98.jpg

 

facd7d9f.jpg

 

1a5574d0.jpg

 

99207a76.jpg

 

2100c76b.jpg

 

79781c53.jpg

Edited by robbs70z
Link to comment
Share on other sites

  • Replies 68
  • Created
  • Last Reply

Top Posters In This Topic

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.

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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 :)

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

Halo bars do not have a 180 degree bend limit but must have the arms extending back to the main hoop horizontal.

 

a. Closed cars

GCR - 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.B) 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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

 

6d91fabd.jpg

 

ec902494.jpg

 

bc0823f6.jpg

 

82373491.jpg

 

d81266f4.jpg

 

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.

 

641fa84a.jpg

 

9a832de9.jpg

Edited by robbs70z
Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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

 

09d443ea.jpg

 

b1e84ee9.jpg

 

900ca044.jpg

 

c93f5525.jpg

 

5699a415.jpg

Edited by robbs70z
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...