Welding torque boxes question

[jcolman]

I have a set of torque boxes I want to have welded to my already finished car. Can this be done with the car on a lift, i.e. the suspension is unsprung, or does the car have to have the suspension loaded during installation?

Thanks

 

[Dana67Dart]

That's a really good question.

I would assume the factory would have welded them in while the body was on a jig. So it would have been in a neutral stress environment.

That being said....

If the car is supported by it's suspension and you weld them in it will tend to hold that shape

If you weld it in with the body supported inside of the torque boxes it will tend to try to hold that shape.

Might be negligible with anything other than a Convertible?

 

[72bluNblu]

Welding them in on a lift shouldn’t be an issue. The torque boxes don’t span a very long area, the likelihood of you capturing some kind of sag and making it permanent with the torque boxes is almost nil. Guys weld their subframe connectors in with their cars on rotisserie’s and I’ve yet to hear of anyone not being able to get their doors gapped and closing properly or their car alignment right afterwards.

If you’re concerned about it, check your door gaps and door alignment before you put the car on the lift and again on the lift before you weld in the torque boxes. As long as there’s no changes there you’ll be absolutely fine.

 

[CFD244]

When I researched the hell out of it for my installation, consensus was that it didn't matter for torque boxes, and loaded for frame ties.

 

[72bluNblu]

When I researched the hell out of it for my installation, consensus was that it didn't matter for torque boxes, and loaded for frame ties.

There's a lot of debate around whether or not they even need to have the suspension loaded for subframe connectors. Like I mentioned there are literally threads on this board and other mopar boards showing the US CarTool style subframe connectors being welded in with the chassis sideways or even upside down on a rotisserie. I have not seen one of those builders come back and say they couldn't get the doors gapped and aligned or the car aligned properly afterward. I've heard guys explain doing it that way to try to remove the 50 years of body sag the unibody construction would have accumulated, allegedly returning the car closer to original specs, but I haven't seen anyone that provided any kind of chassis measurements to back it up either way.

Frankly, I don't think it matters a whole lot unless the chassis has been compromised structurally by rust or had too many panels removed for repair simultaneously. I wouldn't jack up one corner and weld everything up, just in case you made permanent some kind of flex or twist. But as long as you support the chassis in a fairly uniform way it shouldn't be an issue.

 

[CFD244]

There's a lot of debate around whether or not they even need to have the suspension loaded for subframe connectors. Like I mentioned there are literally threads on this board and other mopar boards showing the US CarTool style subframe connectors being welded in with the chassis sideways or even upside down on a rotisserie. I have not seen one of those builders come back and say they couldn't get the doors gapped and aligned or the car aligned properly afterward. I've heard guys explain doing it that way to try to remove the 50 years of body sag the unibody construction would have accumulated, allegedly returning the car closer to original specs, but I haven't seen anyone that provided any kind of chassis measurements to back it up either way.

Frankly, I don't think it matters a whole lot unless the chassis has been compromised structurally by rust or had too many panels removed for repair simultaneously. I wouldn't jack up one corner and weld everything up, just in case you made permanent some kind of flex or twist. But as long as you support the chassis in a fairly uniform way it shouldn't be an issue.

Yup, what can I say. The dude at USCT told me it would probably be a good idea. I guess no one knows for sure.

 

[72bluNblu]

Yup, what can I say. The dude at USCT told me it would probably be a good idea. I guess no one knows for sure.

Doesn't surprise me that's what they recommend. Your car is gapped and aligned and they assume everything works when it's sitting on it's suspension, so, if you do your chassis reinforcement like that then it's pretty unlikely that will cause you any problems. If you lift the car then that introduces the possibility that something could change, which you could make permanent with chassis reinforcement added in that position. So from a liability standpoint, I see where they're coming from.

From a reality standpoint, I honestly think you'd have to try to get the chassis out of whack enough to make permanent changes with a subframe or torque box install. Like it would have to be obvious stuff was moving around when you lifted it. So I say support the chassis as uniformly as you can, check your door gaps before and after, and you're really unlikely to introduce some kind of permanent sag or twist.