dennisbernal91z

iTrader: (2)

I just got to the point in my build where I need to install the roll bar. Something I attempted 10+ years ago as a teenager and did a horrible job. I cut that roll bar out and am ready for a fresh install.

Bought a simple jegs 4 point.

I think the step that I need the most guidance on is the main hoop measurement and trim.

I have checked that the hoop is not warped or bent from shipping.

I then measured from about 0.5" from the inner roof to the trans tunnel, then from the tunnel to the area that the bar will mount to.

I then placed the hoop on the ground and pushed a level against the top of the hoop while on the ground so the flat datum would extend over the legs. I then marked the distance I measured above.

The legs are bent in a bit, should I try and straighten them before I cut?
Is this the method that should be used for marking this first measurement?

I could post the measured distances but figured this wouldn't help my questions, if it does please let me know.

In the pics you can see how the rear of the car looks now as well as the bar leaning against the car with my initial marks made in silver sharpie.

Any advice will be VERY helpful. I will keep searching TGO for pics and tips. As well as the internet in general. Thanks!

redneckjoe

i'd probably straighten it out first before marking and cutting.

if you have subframe connectors, it may be possible to tie into them instead of just welding a plate to the floor.

dennisbernal91z

iTrader: (2)

I will have SFC as well, but trying to have the bars line up with them and dealing with all that doesn't seem worth it at all. Tieing into SFC I think is for guys running CRAZY fast cars. I plan to tool around town and go to shows so it is not worth the trouble.

So you think I should try to straighten the legs first? I guess I can strap it to a lolly column in my garage, ensure that it is 100% vertical, then push the other leg out till it is also 100% vertical. Then make measurements and mark where to cut.

I think I am going to measure from the roof to the tranny hump, then from the hum to the mounting locations. Subtract 1 inch, then subtract 1/8" for the mounting plates. Use the # to then mark down from the top of the main hoop, down the legs when they are parallel and straight. Thoughts?

AlkyIROC

The purpose of a roll bar/cage is to protect the driver. Simply welding it to sheet metal will not give you that protection and it simply becomes a show bar and added weight to the car. Might as well make it out of muffler tubing if that's what you want.

The legs of the main hoop are bent inwards for a reason. You need to weld all around the tube. If they were straighter, they would be closer to the body and you won't be able to get a proper weld all the way around.

Weld in some 6x6 plates on top of that hump that runs behind the front seats. The 6x6 plate does not need to be flat so it can be shaped and bent around the sheet metal. The goal is to have 2 feet of weld holding the plate to the sheet metal.

Determining where to cut the tubes is a lot of trial and error. Make small cuts and do a test fit. It's easier to cut off more than it is to add to the length.

dennisbernal91z

iTrader: (2)

Thanks AlkyIROC. I have the 6x6x1/8 inch plates. They will be used, was there something i said before that made you think i wouldn't?

Thanks for the pointer about the leaning in legs.

AlkyIROC

That right there looked like you were not going to use the 6x6 plates and probably just weld the tubes directly to the sheetmetal.

dennisbernal91z

iTrader: (2)

Hi Alky you are 100% right. That was a misleading comment. I have edited it. My brain must have drifted when I was typing that.

dennisbernal91z

iTrader: (2)

Based on how I want to lay out the interior pieces, I would like to attach the main hoop to it's 6" plates at the location shown in the image.

Any pointers on how to do this?

I was thinking of cutting and grinding the area as smooth as possible. Then bending the plate with a score mark, heat and a hammer. Then weld it to the floor. The pipe will need to have a side cut up on it to weld up there. I could also pull the legs in with a come-a-long strap. Don't know if this would be bad for the hoop to be in stress like that.

AlkyIROC

That's the thing about rulebook information which you are not really using anyway. There is no specific rule as to where it has to be since there are so many makes and models of vehicles. There are guidelines as to what needs to be where but it's up to the builder to determine what position works best.

I can't say if that's a good position or not. Will it interfere with the seats or door panels? Will it be positioned too far forward for the drivers head? You're not wearing a helmet on the street and hitting your head on the tube can be painful. The main hoop should be as vertical as possible.

dennisbernal91z

iTrader: (2)

This position will not interfere with the interior plastic or door panels.

I can install it vertically. It would be pretty far from my head once welded in. I am almost 6 feet. I will put in the seat and steering wheel tonight to measure how far it would be from me.

The idea I have it to tuck it TIGHT up against the headliner so it is out of the way as possible. Rear seat will be gone. I am using this more as a structure enhancement than anything else, but I want to follow as many rules as possible since I am sure they exist for good reason.

AlkyIROC

The higher the better. There isn't a lot of headroom in a third gen. In my ace car, I have the seat in a reclined position to give me more head room. I also don't have any interior to worry about.

Tibo

iTrader: (15)

http://www.spohn.net/blog/2010/12/08...maro-firebird/
Here is a writeup on Spohn's site about installing a rollbar in a convertible thirdgen. It is a good reference and may help answer some of your questions.

dennisbernal91z

iTrader: (2)

Very helpful, thanks.

Still unclear about how the interior parts fit depending on where i weld the main hoop

dennisbernal91z

iTrader: (2)

Basically what I am stuck on is to weld the main hoop in the location of the white circle or the red circle.

I used to have it in the red circle, but didn't love it because I had to cut up the interior pieces. This is less of a concern now because the minitub is forcing me to hack everything up anyways. I figure I will learn to lay fiberglass, and make some new interior pieces. I can do this for the red circle location as well.

So basically, does anyone think one location is better than the other? And if so, why?

I want to get this welded up in the next week or two so I can move on to the SFC and be done with the major body work so I can move onto suspension stuff.

Thanks for any insights.

redneckjoe

IDK if it matters where you put it? my goals were to attach to the SFC's, then weld the plate, and be able to re-install all the plastics. it worked out for me. lots of test fitting.

dennisbernal91z

iTrader: (2)

Have any pics with plastic in?

redneckjoe

not at those spots. it was a ton of test fitting, but got them all in. unfortunatly theyre all out now as i'm working on tubbing the car. i'll see if i can dig a pic up.

dennisbernal91z

iTrader: (2)

I see you are bolting your 5 points to the original rear seat belt holes. Is that better than mounting them to the rear cross bar?

redneckjoe

i don't know? it's just how i mounted them. i have no clue what any rules might be either. i could have welded tabs to the crossbar or also there is wrap around versions to the cross bar if you dont want to weld tabs. i think i was just being lazy?

how's your progress going?

AlkyIROC

I wasn't even paying attention to seat belt mounts. Technically, those will not pass tech.

The over the shoulder belts need to be anywhere from level with the top of the shoulder to 4" down. They need to be secured anywhere in that range. This is so when the body moves forward in an accident, the belts will hold you in the seat. If mounted lower then the belts simply go up your chest and down at the back. This doesn't keep your body held into the seat.

The gray area would be how they go over the crossbar. In that position, they would have more of a straight pull to the shoulders.

It would really be the decision of your local tech inspector to say yes or no. My belts are mounted similarly but I have tabs welded onto the backside of the crossbar.

I can't remember if I've commented on that photo before or not. The door bar is too low. It needs to pass between your shoulder and elbow. It might be nice and easy to get out with it that low but even with that roll bar system, you wouldn't be allowed to run quicker than 11.50. If you want easy access and pass tech, you can install a swing out door bar. Those are legal down to 8.50.

redneckjoe

yes, it's been pointed out before about the door bars. i put them in that posistion so i could keep the factory door pulls. something a may change one day? it's only an 1/8 mile track where i go and they're pretty laxed about rules. they're biggest tech is no leaks, catch can, windows up, seat belt and a helmet if you run 8.6 or quicker. i've asked for a rule book many times with no luck. i guess its the track's discretion? i'm learning as i go.

articwhiteZ

iTrader: (56)

I my self like them lower into the pan.. remember bolt in plate on top and under..
weld in just the plate the tube is welded to..
lower in the pan and all the way back...a tip.. the tube is not centered on the plate..
seat will go all the way back. this shot is before side bars.

main hoop just touches inside window trim plastic. and clears head liner.

a better shot.. note this shot shows no seat back supports. you will need them and should use them.. the ones I have are about $90 ea and 100% adjustable. they came in steel..im having a copy made from aluminum. to save about 3lbs.ea. as there are 2 of them. driver and passenger. they clamp to the cross tube.. then run up to the back of ea seat. so the seat will not flex back..


seats are set lower with a low GM rail.. drops the seat down almost 3". this helps to clear helmets. even on guys that are 6'4"

small details..make for a clean install

like anything the car is never done...so many thing planned for winter

Rancid87

I located the main hoop in mine similar to redneckjoe's so you don't see it when you look at the side profile of the car.

dennisbernal91z

iTrader: (2)

Have any pictures?

I have not been working on this aspect of my car for some time as I decided to redo a lot of horrible patch panels I did when I was a kid.

I should be back to installing the bar in a week or two. More pics the better.

I also am interested in the steps people did to weld the rear bars in all the way. Some people I have seen cut holes in the floor to drop the bars down. From the look of the third gens, it looks like you could tack the main hoop in. Then tack the rear bars in. Cut the main hoop tacks. Pull the assembly out of the car, final weld the rear bars, then put it all back and final weld the main hoop.

Does that make sense? What steps did you guys all do?

Rancid87

I don't have any pictures handy since I did that project several years ago now.

Your method is how many people do it since it allows easy access to complete the welds. I did mine in place and it was kind of a pain to get the top of the rear bars to main hoop. If I were to do it again I would tack everything in place and then cut the tacks and remove to weld the rear bars to the hoop.

dennisbernal91z

iTrader: (2)

Perfect. I will use this method. Once I get around to figuring out how to finish m floor boards I will move onto the bar install.

Thanks.