structual body work questions

[rb70383]

Its not a PT project but a tow vehicle. I want to graft a Dodge Ramcharger body on the back of a crew cab cab. Any one basically cut a car in half and rejoin them? Looking for some pointers and tips.

[jaybee]

Are you saying that you want to graft the back half of a Ramcharger body to the back of a crew cab, effectively making a 4 door Ramcharger?

[rb70383]

Yes just like this one.

I am thinking of using the pinch welds to help line the 2 bodies up. Good? no?

https://static1.pt-content.com/images/pt/2008/10/dodgelimo-1.jpg

[Mathius]

Someone can correct me if I'm wrong, but I think the structural part is going to come in when you stretch the frame. On a full framed vehicle, the strength of the chassis isn't AS big a deal I don't think. I'm not saying you can glue it together, either, but as long as you weld it all the way around, and possibly put some braces in so the roof won't collapse on you, I think you'll be alright as far as the chassis itself.

But unless you can find a frame with the exact same wheel base already the length you need, you're almost certainly going to have to stretch the frame, and possibly re-locate the rear axle, and maybe add a driveshaft and/or carrier bearing setup.

Mathius

[toxicz28]

You can use the pinch welds to line up the two sections of body. And, as my esteemed colleague said, the structural part of the job will be if/when frame modifications need to be done. However, the frame strength is important, especially on a tow vehicle. If you do need to modify the frame, be sure to weld reinforcement plates to the frame at the welds.

[rb70383]

Been doing research and thinking a ext cab frame 8' bed "should" work by putting a crew cab on it along with a ramcharger body which is actually shorter than a short bad truck. I just need to find a usable crew cab then I can do the final measurements.

[Mathius]

You can use the pinch welds to line up the two sections of body. And, as my esteemed colleague said, the structural part of the job will be if/when frame modifications need to be done. However, the frame strength is important, especially on a tow vehicle. If you do need to modify the frame, be sure to weld reinforcement plates to the frame at the welds.

Yes, I didn't literally mean weld solid all the way around. You CAN, and then grind it down. Or you can run a series of stringers, or tacks. My point was to make sure you get welds all the way around the seam.

If you choose to go with tacks or stringers, make sure you get some seam sealer to go over your seam so you don't get a corrosion problem later.

As far as the frame goes, I've heard people say Z'ing the frame makes it strongest, but I'm not sure I agree. Provided you weld it properly and box in your frame and put the proper crossmembers in (you are extending it afterall) I think it should be more than solid enough no matter how you make your cut, but then I've never attempted this before. But the idea is a good weld should be just as strong as the parent material, so I would think the extra re-enforcement should be added from an engineering standpoint, not a "lets make double sure my welds are strong enough" standpoint.


Been doing research and thinking a ext cab frame 8' bed "should" work by putting a crew cab on it along with a ramcharger body which is actually shorter than a short bad truck. I just need to find a usable crew cab then I can do the final measurements.

You need to ask yourself what you're going to be doing with this vehicle as well, because if you're using an extended cab frame, you have to remember it isn't going to have bushings to seat the rear half of your chassis. You're going to have to fab up body mounts on the frame and come up with bushings. Particularly if you intend to seat passengers back there, but even if not, you're going to want the chassis to ride correctly.

Mathius

[jaybee]

Yes, Z the frame, don't just use a butt weld all the way around. If you do that a crack at any point will just follow all the way around. Plus a Z will give you more weld length, therefore more strength. Reinforcing plates inside the frame and attached with plug welds will also help spread the stress so it isn't all taken by the frame splice. Your sheetmetal will need to be stitch welded continuously anywhere it can be seen, otherwise any filler you use will crack in the spaces between welds or absorb moisture from the backside and rust. In the floors and other hidden areas you can tack weld and seam seal.

[rb70383]

I have a parts ramcharger that will have all the body mounts/brackets required. I plan boxing the frame and rebuilding the cross members out of tubing and then weld them to both walls of the boxed frame. The parent truck is a 74 power wagon 4x4. I am also going to swap in a 12v cummins and driveline. She will be a tow vehicle and a get away camping vehilce as well. I have the service manuals for both vehicles. I have heard "Z"ing the frame as well for the same reason. More welded area. No passengers in the back. that is the unofficial "sleeping" area. :)

Is it possible to get 2 long sections of angle iron, place them as a "v" build a supporting structure and place the pinch welds in them. That way I can slide the bodies together and square em up as needed. I dont have a chassis table to place them on. :(

[Mathius]

Is it possible to get 2 long sections of angle iron, place them as a "v" build a supporting structure and place the pinch welds in them. That way I can slide the bodies together and square em up as needed. I dont have a chassis table to place them on. :(

I'm really not sure what you mean by that whole 'v' thing. Do you have access to a chainhoist or something? A regular old car jack would work, and then a bottleneck jack. Just keep sticking 2x4's under there until you get the height you want. Is that what you're trying to ask about?

I'm not sure what you need.

Do yourself a favor though. Get some tubing, or angle and weld it across the cab on both sides before you make your cut, to have something to keep it from collapsing, or your job will get 100 times harder.

Mathius

[jaybee]

Ditto cross bracing the cabs BEFORE you cut them apart. I'd also advise making patterns of one of the cabs and compare to the other just to make sure there isn't some subtle difference in cab shape. Your job could get a lot harder or easier depending on just where you make your cuts.

[rb70383]

So doing some more building in my head, thinking the best would be to actually cut the front of the ram charger body insode the door opening and the back off of the crew cab in the rear door opening. That way I just adjust the bodies to match the orginal door opening. I think that would be the best way.

[jaybee]

As long as the rear door opening of your crew cab has the same shape as the door on a Ramcharger I'd say that's a great way to go. The quick way to find out would be to make a template of one door and compare to the other.

[Jim Nilsen]

I am curious as to whether or not you have to have this vehicle inspected in your state? I can remember getting notifications that in some states it is not legal to section vehicles. Although this was brought on by people who would take the good front half of one and mate it to the good back half of another it was still made illegal in some states. This is why some states can't make limousines that are stretched. These laws weren't made because it can't be done correctly but because some poeple didn't do it correctly. I don't want to rain on your parade but make sure you don't live in one of those states and need an inspection to get it back on the road when done.

This sounds like a cool project and you seem to know what you want and need. It would be a drag to get it all done and have the secretary of states office not give you the authorization to drive it.

Goodluck