Before I seperate the body from the frame on my 73 I want to make accomidations for mounting a future 6 point roll bar. My plan would be to use 6" or so tubing "stubs" welded to the frame, make the nessesary holes in the body to accomidate these stubs and then add the roll bar at a latter date. I want to do this as future access to the frame would not be easy and I will be getting the frame powercoated so I would like to make all of the frame mods before I remount the body. Has anyone ever approached it this way or am I way out of line ??? I am not in need of a full cage as this car won't be a racer, just a occational 1/4 mile blast and I want to make sure its legal.
If you leave "stubs" that means you will need to butt weld the tubes when you add the rest of the roll bar. NHRA has a very specific procedure for butt welding roll bar tubing. You cannot just butt them together and weld them. It involves placing a sleeve inside the tubing as support and welding the three pieces together. See the rule book for the exact detail. This may affect your decision. Have fun.
Thanks Jeff, I was thinking of using the sleeve anyway. I will need to get my hands on a rule book for the fine details. The info I have been pulling off of the web has been a little grey and only provides the basics... In short - what I want to do is not unheard of ???
Well, I've never heard of it, but it may have been done before. Based on my experience fitting and installing rollbars/cages, I know you have to be pretty exact to get all the angles right and to get everything to fit and look nice. My thoughts on the stub idea is that you will have to make double sure that everything is at the right angle so when when you install the rest of the bar it will line up on the other end and not have kink in it. Just some thoughts. Interesting idea though. Have fun.
Jeff is correct. Angles and fit make this a bad plan. If you are just planning a six point cage, do it now. Costs shouldn't be the main factor as these type cages are easily obtained from catalog. If you plan on bending your own tubes, now is the time. You can tuck in a nice set of tubes with the body off. If you were to factor in all of the extra labor involved in doing this in two steps, you'd lose your shirt. Also, you'd be doing welding in a finished interior compartment which is always a scarry event. Do it now. Another thought is how fast do you plan on going. IHRA is 11.50 and NHRA is 11.99. If you only plan to race at the GSCA Nats, you don't need one. They have let 10 second cars run without cages. I also suggest using .083 CM tubing and a good TIG welder. Good luck.
