I was busy this week and let the roll cage post go. George brought up a good point on mounting the bars to the frame but I missed it.
I have been thinking more and more about installing a cage, not a roll bar but a full cage.
I want the rigidity that it provides plus I am starting to play harder and harder and want the protection.
I have built a number of cages in the past and the car really feels different afterwards. I particularly notice it pulling into driveways. The car feels really solid.
IN the past I have only built them of 1 5/8th stainless for good lucks and my pipe bender can do a good job on that size but they weight too much for my vet.
I am looking into chrome moly but the down side is the price and far worse HOW to weld??
Tig is the only solution that I know because you have to use 4340 wire as filler. Also tig is more controlled going around each joint.
A rear roll bar is simple because the frame is exposed in the wheel well and you can plate the frame on top and weld the bar to it.
I do want a full bar over the top of the windshield and comming down the window posts in front. I also want a bar through the floor connecting as far into the engine compartment as possible.
I also want side bars. They will have to be swing out, I am not going to crawl over any bar. The mustang has more room and the wife would not be impressed with climbing over a side bar regardless of how safe it is.
Bending chrome moly might also be a problem and until I can get a sample piece I don't know how good a job I could do.
George I would like some pictures of your full cage and repeat the other post on how it was mounted to the frame.
Thanks

 

Norval, I've got a full chromemoly cage going in mine right now along with the back half. I wish I could help you but I have a buddy of mine doing it (in Washinton state) You will have yours done before I get mine back.

Good luck

 

you are hinting at the mounting by the a pillar right since the other pos. are not that much of a prob. Here's how most of them mount, with their own pedestal welded to the inside of the frame rail.

 

Twin turbo that is a race car where looks don't really matter. I want my cage to blend into the car, hug the roof line and the pillars, not stand out. I am also concerned with how it passes through the fiberglass floor. Can I glass the bar right in. Make it totally water proof? Does the body flex on the rubber mounts causing a cracking problem if the bar is glassed in??
George has the only full cage that I know of, once again roll bars are easy. To me the hardest part is the front down tubes, keeping them close to the window pillar and trying to get them to blend in.
Fuel lines and brake lines need to be moved.


John this would be a winter project, I do not take the car apart this time of year. If would keep me busy this winter. I also have to be concerned with raising the car in the air for work underneath that the car is level, in it's normal position even when on blocks. I don't want the frame twisted and weld a cage in in this state.
Filler rod/wire is very important with chrome moly.
I wieghed stainless this morning and get 14 ounces to the foot. That is almost a pound for every foot of pipe. It adds up too fast for me.

 

It will blend in, this guy has a custom floor, on our cars the only thing visible will be the tubing, not the mount. If you want to seal up the bar to the floor, glass around it so it's pretty snug with some space and then use windshield adhesive to seal it up, that's how I did my firewall. The adhesive will not cure to a hard compound but will stay flexible.

 

Where the guy cut through the floor he bent white painted aluminum sheet metal and pop rivited it around the bars. It actually has 1/8 - 1/4 inch gap so the body can move on it's rubber frame mounts. I then sealed it with silicon caulking.



This is an older picture but I was doing 4000 rpm in OD coming to work today on the freeway My speedo reads slightly fast. I've also driven it at 7000 rpm at Bonneville Salt flats with 300 mph rated tires

1000 7 12 20 29 0 0
1500 10 19 30 43 0 0
2000 13 25 41 58 0 0
2500 17 31 51 72 0 0
3000 20 37 61 87 0 0
3500 23 44 71 101 0 0
4000 26 50 81 116 0 0
4500 30 56 91 130 0 0
5000 33 62 101 145 0 0
5500 36 68 111 159 0 0
6000 40 75 122 174 0 0
6500 43 81 132 188 0 0
7000 46 87 142 203 0 0
7500 50 93 152 217 0 0

 

mine is a custom done by a local race shop. .130 wall seamless 1 3/4 mild steel which exceeds the SCCA or NHRA requirements.

With me it a personal safety item. I'd have it even if it wasn't required. I feel much better with it.

Norval - The front of the door bar which goes through the floor about mid calf. Required welding a 4X6 inch 3/8th plate to the bottom of the frame under the door with about 4X4 of it hanging inboard. So the cage pipe comes down on top of it on the inside of the frame rail

From just under the dash you put a pipe going forward nearly a straight shot that attaches to the frame rail just behind where the engine mount is.

 

That's probably what i would have to do too. Twin turbo has another solution with the pedestal comming through the floor and welded to the side of the frame then welding the bar on inside the car.
I will have to look at the price of chrome moly vs mild steel and decide from there.
Also have to break the news to my wife that I want to deface the car with a cage. She hates the mustang now.

 

Norval, the roll cage is definitely a two-edged sword for our cars. There is no doubt about the extra rigidity and safety but there are a number of downsides.

Here is why I am resisting putting one in my '67:

1) I see is the potential for damage to the interior when welding and fitting.
2) The loss of interior room.
3) Ingress/egress problems.
4) Cutting up the interior.
5) Movement of the body/fiberglass when driving.
6) Not being able to remove the body from the frame without cutting the cage out. So far I have removed the body from the frame on my '67 a total of 3 times.

I recently cut the roll cage out of my '69 Corvette in order to return the car to stock. What a pain in the butt getting it out! I experienced most of the above listed problems. I felt very confined while sitting in the car with the cage.

I would really like to see George's car in person to see what kind of job was done and how he lives with it on a daily basis.

Steve

 

Norval - Just explain to her about safety! I also think that it looks good. I have the swing out kit and I was going to just do the passenger side. I kind of like the fact that none of my bigger friends even ask to drive my car

632 - it's PITA and the upper hoop needs to be moved out because my helmet always hits the side bar.

My 5'4" wife - her feet actually don't reach the petals with my non adjustable racing seat.

 

Bad things:

Getting in and out.

The windshield down bar makes it a reach around for lights and wipers switches.

Yes, you would have to cut the cage out to remove the body.

The top hoop is a compromise to allow room for the TTop handles.

Between the tall Sparco seat and the rear bars it makes for a really bad blind spot off the drivers rear quarter panel.

On my 3000 mile trips the front floor bar rides against of my calf and it gets to me after about 8-10 hours in the seat.

The worst thing is: The harness side to side bar is near the center so I can't fit a cooler or my slicks in back anymore.

 

632C2 I agree with everything you have said. I hate cutting up the interior, I hate the how the cage encrotches on the interior space, I do not want to leave gaps between the body and floor for movement and I too worry about pulling the body and having to cut the cage out.

George as for getting sore after 8-10 hours I have never ever driven that long. I look at 3 hours as a long trip.
I couldn't fit slicks in my car now.

I learned alot about welding chrome/moly today. NO NOTS. Do NOt use 4340 as a filler rod, use mild steel to prevent cracking. DO NOT mig weld it. It causes cracking problems. Tig it and use mild steel as a filler rod.

I was hopeing to put the top hoop in the groove on my T tops.

 

norval. I can send you some pics if you want. Mine is certified to nhra 7.50,I dont know anyone going as fast as mine. Use mild steel ,do not use chrome moly for anything on the street.It will be flexed out and not true after a few seasons. The difference in weight is only 75lbs on a full cage.Mild steel much more rigid for street bumps etc.If wanted you can put chrome moly x bars in later on the doors.Swing out bars are popular on slower cars.Yes you can glass in the entire floor. I glassed in my entire wheelwells over the steel tubs . Totally sealed so I dont fill up with smoke after a burn out. My body does not Have a problem with the body mounts.Does not crack.The car will be much more solid.If my chassis wasnt set up right ,my engine would rip it in half.MY 63 pro mod im building will be chrome moly,but thats going to be a 6sec race car.

 

norval. I can send you some pics if you want. Mine is certified to nhra 7.50,I dont know anyone going as fast as mine. Use mild steel ,do not use chrome moly for anything on the street.It will be flexed out and not true after a few seasons. The difference in weight is only 75lbs on a full cage.Mild steel much more rigid for street bumps etc.

I would love pictures. My email address at home is nwilhelm@rogers.com Don't worry about the size, I like them big.
As for chrome moly vs mild steel, Mild steel is just that , mild, low densile strength. Moly is much stronger. 75 pounds is alot of weight. My complete 6 point mustang cage only weighs 75 pounds. The 1 5/8th tubing I normally use is 14 ounces to the foot so the weight can be eaily checked/calculated.

I would glass the bars to the floor, I will end up using standoffs from the frame through the floor and do the welding in the car rather then try directly to the frame.
I am fighting the idea of cutting up the car but I know it is something I should do for saftey and rigidity.
If the car was a unibody I would not hesitate, it would have been done years ago but it is glass and 2 piece so I am reluctant. I am running all the ideas around in my head, I really like the idea of standoffs through the floor, I know I can do a really good job of them, make them look professional.
It is still a long way until winter and the car is on blocks but I will continue to run the ideas through my head.
Have a nice evening

 

I will get you some pics. If you want to use chromoly go for it. Not rec on a street driven car as it will not hold up. As far as mild steel versus chromoly it is stronger but way more flexable and tends to get distorted and out of shape after use. Mild steel will keep its integrity in a street driven chassis.75lbs is nothing unless your going to make the car completely race only,and every other item has been shredded.On a street car with limited traction you will never notice it.We learn by our mistakes.Sometimes you have to do it yourself and find out.

 

I will have to do some thinking. You know your stuff, George used mild steel, it is alot cheaper and I could add a tooth or two to the blower to make up the weight difference . That was George talking.
George if you have some other shots of the cage I would love to see them also.
I never knew chrome moly wouldn't stand up. Talking to material guys they do nothing but praise moly. We build a mini indy car every year and all tubing is moly. Mild steel would make it easier to swallow the mistakes. Unless a tube is perfect I will not use it.

 

I'm thinking of a roll cage to stiffen the car, but I'm concerned about my (or my passenger's) head banging the bar in an accident. It's one thing to be racing with a helmet, but on the street it looks like it could be dangerous (see the picture of the lady above). Is anybody else concerned about this?

Thanks, Paul

 

I do have a 4 point harness in my car now. The boys veto'd the crotch belt but it could easily be added .
When I have a passenger my driving totally changes. The passenger is usually my wife and I want to impress her with nice safe driving. Alone I drive alot differently and that is when I need the cage.

In the catalogue I see tubing and it says D.O.M. What does this mean?? All the tubing is either .085, .065 or maximum .095. Is this thick enought to meet specs and if not why is it offered for race car buildups??

 

Norval. I would gladly send you a tube notcher and chassis book I have written by the guru of chassis building both race and street.You can use them til your project is finished and then return them.Lots of info that most people dont even consider.There is way more to tuning suspension than just putting big tires on. Chromoly is used as part of the chassis tuning because of its ability to flex.This flex is set up to help plant the rear wheels.On a cage it doesnt take well to street bumps ,driveways,potholes unexpected hard road conditions.It becomes stressed and out of shape.Then the car doesnt go straight under acceleration or stopping.On a race car they are worked on constantly and never see the pifalls of streets.The chromoly can have the same strength as mild steel with thinner wall tubing thus lighter.The mild steel will be stiffer and can take more abuse.Im sure if you went chromoly you would be fine .If it does become overstressed,very easy to do in a 3000lb car driven on the street,your car will not react like you want it to.Lots of people build them and cage there cars .Very few ever track them or go straight like they should.Even pro mods went to double frame rails to compensate for the chromoly they use in a heavy high horsepower car.Email me your address and I will send it out to ya.

 

SuperCobra - I actually have the thick high impact racing certified stiff molded foam 1 3/4 bar size strips that run on the inside of the upper hoop. They velcro in place. so each side has an 18 so inch strip. You get them at Summit racing. The pieces are about 1 inch thick.

I have a stock 79 passenger folding seat for rear compartment access and the seat is actually lower. So as a passenger unless your 6' foot or better your head would not hit anyway.

My car is really only for fun and built around my 5'10 and 170 lbs