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Body Reinforcement
https://slantsix.org/forum/viewtopic.php?t=57948		 Page 1 of 3
Author:  ILMopars [ Thu Jun 25, 2015 12:01 pm ]
Post subject:  Body Reinforcement
I an going to be repairing the body of my Dart and I would like to know what are the weaknesses of the body. I will not do subframe connectors as the car will be outwardly stock. Here are my ideas so far and I would like to know if I am missing anything?

Door Anti-Intrustion Bars
Full Welds on Door Window Frames
Extra Welds on inner structures and all seams

Thanks in advace
Author:  GTS225 [ Thu Jun 25, 2015 3:36 pm ]
Post subject: 
Yes, you are missing something. The biggest weakness of the body is that it's a uni-body.
The refusal to put in subframe connectors, whether bolt-in or weld-in, is not going to help the value of the car.
Installing them will also not hurt the value of the car, and may, in fact, increase the value.
As you put it, you don't want to change the outward appearance. Subframe connectors don't show from the outside, unless you're crawling around on the ground and looking underneath. They stiffen the overall chassis, and make it stronger, and arguably safer.

Door anti-intrusion bars? Care to clarify what you're talking about?
Full welds on the window frames? That will hurt the originality of the car and decrease it's ultimate value, while doing little to make it stronger or safer.
Extra welds on inner structures and seams. Yes, that will help to make it stronger and safer, but will also harm the originality of the car. If you're going for originality, collectability, and monetary value, anybody worth his salt is going to see those discrepancies and advise the potential investor to steer clear.

But it's your car.
Perhaps I should ask this, though; What, exactly model and trim level Dart do you have?

Roger
Author:  Dart270 [ Fri Jun 26, 2015 6:20 am ]
Post subject: 
Hi ILMopars,

Perhaps you can tell us more about your car, your goals for it (street driving, show, race...), and your budget and/or facilities for making modifications. This will help us give tailored advice.

Has the car been rusty before, or is it rusty now? If so, where is/was it rusty? That makes a big difference.

I have driven a 68 Dart for 27 yrs on the street and dragstrip. It has 250k miles, but has very little rust. I put in subframe connectors about 5 yrs ago when I installed a turbocharger. I cannot say I noticed a big difference, but I could notice something. I have done no other body strengthening. I can say it is noticeably more flexible under certain conditions than when I got it in 1988.

All the best,

Lou
Author:  SlantSixDan [ Fri Jun 26, 2015 9:32 am ]
Post subject: 
I agree with GTS225: subframe connectors, quality ones such as these, will vastly improve body stiffness without spoiling the outward appearance of the car at all; they should be a priority. Even better would be this.

Door anti-intrusion bars are a good safety improvement. Might be easiest to get them by bolt-on swapping on '73-up doors which (by law) have the anti-intrusion beams already present.
Author:  Joshie225 [ Fri Jun 26, 2015 9:49 am ]
Post subject: 
After putting extra large subframe connectors in my '66 Dart I noticed a lot of flex forward of the firewall. If you visualize the chassis as pair of springs with the firewall as a bulkhead between them it is easy to see that I made the rear spring very strong, but did nothing for the front spring. This is a real problem for the front suspension and for handling. To reduce that flex I would have needed to do work forward of the firewall and the US Car Tool kit looks like a very good option. It's amazing how much the front end flexes and twists when you put on sticky tires and suspension to match.
Author:  ILMopars [ Sat Jun 27, 2015 2:05 pm ]
Post subject: 
Well, I know the car is a unibody. I am fully informed of that fact. My idea is to make a car that is fun to drive, can do 365 days of driving every year and be comfortable. Also for it to be able to blow some of the hardtops out of the water at shows. I was thinking about welding some square tubing on the inside of the rockers, and welding a bar across the back under the package tray and one behind the rear seat. I have however heard of something called stealth connectors, but I am not sure if it has any truth to it.

My main focus is occupant safety. I'm not looking for an IIHS Top Safety Pick + but I want to improve crashworthiness overall.
Author:  SlantSixDan [ Sat Jun 27, 2015 3:36 pm ]
Post subject: 
Quote:
My idea is to make a car that is fun to drive, can do 365 days of driving every year and be comfortable.
So you won't install subframe connectors because…?
Quote:
was thinking about welding some square tubing on the inside of the rockers, and welding a bar across the back under the package tray and one behind the rear seat.
I can't think of a reason why not to reinforce the rockers, but overall this sounds to me mostly like random metal welded into random places that probably won't accomplish much in the way of safety improvement.
Quote:
My main focus is occupant safety. I'm not looking for an IIHS Top Safety Pick + but I want to improve crashworthiness overall.
Good goal. Side impact beams are a good part of that. You should also prioritise upgrading the seatbelts (read the whole thread). But don't just focus on crashworthiness, also focus on crash avoidance with better brakes, better handling, better lights -- there is a mountain of fraudulent/dangerous/illegal junk on the market, but even if you disregard all the junk, there's still a wide range of good, effective, safe, legal options including good halogens, good LEDs, and good BiXenons for the headlamps along with relays, good upgrades for the tail/stop and backup light bulbs, and a 3rd stop light, etc.
Author:  ILMopars [ Sat Jun 27, 2015 4:55 pm ]
Post subject: 
I'll read between the lines and state the obvious, by saying that it is the best route to reinforce the rockers and install the subframe connectors. If the underside being stock is out of the question then maybe torque boxes are a good idea too.

If it sounds random then it may be but it is my way of trying to brainstorm the best places to put discreet braces so that it can withstand some major side impacts.

As for avoidance, like you mention, I will be making upgrades as well. Brakes, 10 Drums, possibly KH discs up front (worried about pin design rusting up), HD suspension, HD shocks, sway bar, better incandescent bulbs where applicable, headlamps are TBD, etc.
Author:  SlantSixDan [ Sat Jun 27, 2015 5:22 pm ]
Post subject: 
Quote:
As for avoidance, like you mention, I will be making upgrades as well. Brakes, 10 Drums, possibly KH discs up front (worried about pin design rusting up)
If you're going to the work of a brake conversion, put in discs of one kind or another. Can't imagine why you'd be afraid of any of the numerous '73-'89 big-bolt discs rusting up while not being afraid of the '66-'72 KH setup rusting up; that doesn't reckon.
Author:  GTS225 [ Sat Jun 27, 2015 5:53 pm ]
Post subject: 
I have to agree with Dan on the brake upgrade. The later, large-pattern discs are most likely your best choice, as they are single-piston, where the K-H brakes are multi-piston, and the K-H's are pricey nowadays, and are harder, (if not impossible), to get parts for. If you get a K-H setup that needs a piston or two, for example, you might want to research where to get them and how much it'll cost. Will it "require" you to switch your rear to a LBP?...only if you don't want to carry two spares with you.

I think I see where your thought processes are going. The A-body is a uni-body structure, and being that it doesn't have subframe connectors from the factory, the rockers are the structural members between the wheelwells. You are correct, in as far as that applies, and your thinking of an additional box tubing behind it isn't so far out of understanding, being as you pointed it out. I think I can agree with you on that point, and side with you on the addition of extra "meat" in that area. I'm not so sure you need box tubing there, and suggest you consider angle steel in the floor-to-rocker interface. It'll do what you want and be a touch "stealthy" if that's what you're after.
The torque boxes are also a good step. Mopar put those there for the big block and Hemi Darts in order to strengthen critical points in the chassis. The addition of them won't harm the car at all, but you can go even further with the subframe connectors.
I haven't heard of anything called "stealth" connectors, but that doesn't mean someone hasn't devised a hidden or disguised form of the same thing. It might be possible that what you've heard about is a home-brew connector that was installed inside the passenger compartment, in the proper location to connect the subframes. That's gonna take a bit of footroom away from you, but it's do-able.

I feel obligated to tell you, though, that if you're going after concours-type shows and points, anything you do to the car that isn't absolutely original to that car and that trim level will cost you. Those guys do thier research, and if they don't then the other contestants are there to cry foul. Trophy hounds are like that, and why I stay away from trophy shows. It just isn't worth the extra hassle.
Do it like the hot rod boys over on the H.A.M.B. do it.....build it for you, and no one else.

Roger
Author:  GTS225 [ Sat Jun 27, 2015 6:04 pm ]
Post subject: 
Just re-read your posts, and noticed where you said your main focus is occupant safety. I'm not saying to give it up, as you can improve what you have available to you, but you'll never get the "occupant safety" that modern, computer-designed chassis can give you. "We've" come a long way in the areas of crumple zones and chassis design geared toward "crashworthiness", (as much as I hate to say it), but without a major re-design of the A-body chassis, it can't be done, (if your goal is modern safety standards).

Just sayin'

I do have a suggestion; Google an image search for drag racing and stock car chassis design. You may be able to incorporate and idea or two into what you're trying to do. Many chassis, of both types, have a cross-bar setup right behind the driver. You might be able to do something similar behind the rear seat/below the package tray. Just make sure you tie it in with the subframes.

Roger
Author:  kesteb [ Mon Jun 29, 2015 9:27 pm ]
Post subject: 
Quote:
Well, I know the car is a unibody. I am fully informed of that fact. My idea is to make a car that is fun to drive, can do 365 days of driving every year and be comfortable. Also for it to be able to blow some of the hardtops out of the water at shows. I was thinking about welding some square tubing on the inside of the rockers, and welding a bar across the back under the package tray and one behind the rear seat. I have however heard of something called stealth connectors, but I am not sure if it has any truth to it.

My main focus is occupant safety. I'm not looking for an IIHS Top Safety Pick + but I want to improve crashworthiness overall.
Buy a new Dart. It will have all that stuff already installed.
Author:  SlantSixDan [ Mon Jun 29, 2015 9:55 pm ]
Post subject: 
Quote:
"We've" come a long way in the areas of crumple zones and chassis design geared toward "crashworthiness", (as much as I hate to say it)
Why do you hate to say it? That progess is worth celebrating. Many more people are driving many more cars many more miles, but the traffic-related injury and death rate is far lower than it was when Slant-6 cars were current. And the air's cleaner, too. Those are huge achievements wrought by human ingenuity nudged along by appropriate oversight (regulation).
Quote:
Buy a new Dart. It will have all that stuff already installed.
:lol: Yeah, what he said! (though unfortunately the new Dart is not as good a car as others in its class).
Author:  GTS225 [ Tue Jun 30, 2015 3:37 am ]
Post subject: 
Quote:
Why do you hate to say it?
*********************************************************

Because we've lost so much in style and individuality in automobile design. Anymore, if one were to park 6 different manufacturer's cars together, of the same class, one would have to look at the badging to tell who made what. Gone are the days of taking a bit of risk in auto style to lure in the buying public, and it's really too bad.

There was a time when automotive design was heavily infuenced by current events, and nearly an art form. It would be nice to see some of that make a comeback.

Roger
Author:  wjajr [ Tue Jun 30, 2015 3:45 am ]
Post subject: 
Body reinforcement as mentioned above torque boxes all four corners as used in big block & convertibles. Perhaps replacement of front cross member and inner & outer rocker panels, and front sub-frame Rust t Caps would bring back some of that new car tightness that old fatigued structural members with to many cycles to failure can't. These parts are available from AMD top quality stampings true to OEM.

There are under radiator reinforcement parts that can be added that would reduce some of the frontend twisting as well.

Take a look at this page for different stiffening parts available off the shelf from a Mopar parts supplier so one need not reinvent the wheel with these engineered parts; also they have other handling up grade parts to get these old heaps handling like a modern car.
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