Rubber body mount play a big part in keeping vibration out of the interior. You may find yourself bouncing pretty hard without them. Also, old frames were made to flex. That's why they were rivited, not welded. If you weld the body to the frame, and the frame flexes, you could find yourself in a very interiesting position. Craig
I have a couple thoughts. Just thoughts though. If you weld the frame solid to the body, and you put a heavy load or hit a huge bump, with no room for body movement are you going to twist the body causing gaps to open, doors to pop, windows to move, etc?? Just thinking of why NOT to do it. One thing is for sure, if you want to ever pull the body off for paint, modifications, frame repair, anything at all.... it's not going to happen! (obviously) Personally, I like the idea of being able to take the cab off if needed. We've had our coupe body off and on probably 20 times to check fitment, make mods, etc. Just input though. Maybe someone has a better idea of why NOT to do it. Seems like it would be stiffer, but maybe not enought to make it worth it. May not be worth if for flex reasons though also. Sometimes it's not always a good idea to have things so stiff. A lot of vehicles are designed to flex a little bit for vibration, suspension, etc. Keep that in mind.
Why would you want to? It's gonna make the ride harsh as hell, and will probably stress crack the cab. If you want to stiffen the chassis build a cage. Unibody cars are designed as a complete structure, not just a frame welded to the body. I don't know if you ever going to sell the truck, but if I was looking at something that was welded to the frame, I'd walk away, no matter the price.
No, it doesn't look like it was built to sell BUT you never know when the right offer will cross your path. That said, if they want to buy it they'll know it's welded together. If the chassis is stiff and rigid with the cross members, what advantage would you get from welding it all together? I agree that it's not that far off off a unibody if it's all welded together but if your chassis is built beefy enough you won't really gain anything. If you mount the cab with bolts and rubber isolation pads you can remove it body if ever you should need to - painting, repair, different cab, etc... I'd personally bolt it on and have the flexibilty (no pun intended) to cahnge things if you like. If after that you drive it and decide welding is the only way to go, then weld away.
Just do it! hahaha I've seen a few 'A' roadsters that had the body welded to the frame. You could always cut it out around the floor to remove the cab if ya really needed to.
I don't know . . . looking at the truck and the little area it consumes, maybe it wouldn't be a big deal . . . if done right it could actually help triangulate the chassis and keep it stiffer. I'd pay attention to motor mounts and other items though, unless you like harmonic vibations and other noise eminating about 3 inches away from your skull . . . for hours on end . . . motor noises are one thing. Fatigue from rattles is another.
look at the uni body 60s/70s chryco cars. every one that gets driven hard, has a crack under the windshield, passenger side, near the fender. stress cracks from movement focused on one spot. My uncle has 4 restored mopars. he fixed all of them. he drove a few miles, and the crack came back. in all four. newer unibody cars have alot of engineering done to make it work. The stress is evenly distributed with varied thicknesses of sheetmetal and adhesives that "give". That cab doesn't. It was MADE to bolt on. It has to be able to wiggle here and there or windows will pop. unless you putt around like a grandma, and I doubt that. but I changed majors cause mech. engineering is as fun as backyard engineering.
Let's talk about unibody construction for a minute. Correct me if I'm off here, but I believe unibody construction came in for a few simple reasons. 1) ease of construction and manufacturing (combining frame and body) 2) safety capabilities (allowing drop out motors, controlled crumple zones, etc) 3) less fabricated "rolling chassis" components (I.E. no seperate frame and body independently structured) so the overall vehicle becomes lighter weight. Unibody construction really is designed (or is now) to work as a system to support overall performance of the vehicle in combination with cheaper and easier manufacturing... Ultimately speaking... the car companies found this is a cheaper, more efficient way to get higher porformance out of a vehicle. Don't get me wrong, not be harsh or saying you should or shouldn't just trying to help identify facts associated with the concept. I'm for whatever works and here to learn... I look at it this way, your Willys doesn't meet ANY of the above criteria. You're not using modern suspension that works as a system with the rest of the car, you could care less about manufacturing costs and/or the weight or ease of construction and I'm guessing safety isn't the first thing on your mind or you would be building a Volvo or something. That's my take. Doesn't mean it's right and not trying to be rude or be a jerk. Can't wait to see that truck done actually! Nice build so far!
Isn't metalshapes roadster welded like that? I'd like to know what he says. I would think a lot of hotrods don't have much for rubber body mounts and the bodies are probably bolted pretty solid to the frame. Are you going to incorporate a rollcage too? I think you could probably take most of the flex out of the frame if you wanted to.
All of the Lincoln Zephyrs were welded direct to the frame. I think that you need some interior strength in the cab if you weld it. All twist will go to the body.
I think the difference between this and the manufactured unibody's is that a unibody car has a body that stretches the whole length of the car, where as this just has a cab in the middle of the chassis. If it was welded, the center section where the cab is might be more ridgid than the ends where the axles are, putting a lot of twisting stress on the cab, which could result in body tears or sheetmetal buckling (would be hard on bodywork) I would think isolating the cab with mounts would be the best way, although I haven't ever welded a body to a frame myself.
I've seen my fair share of old duece racecars welded right to the nice swoopy rails. I dont know that there is anything wrong with it. Especially if you are just going the ratrod build route. I personally think it is a copout and just lazy. I have a Huge sign above my workbench that says "Don't be LAZY, do it RIGHT" that thing keeps me honest. In your case. I'd make a 1x1 truss setup for the cab to sit on top of the frame rails. Drill straight through those and into the frame rail. Add a hockey puck, or even go holesaw up some old truck mudflaps to use. You just need something to isolate the cab. Good luck, godspeed, and get that thing going!
Hmmmmm......my '68 Charger has over 250,000 miles on it with NO cracks. And I drive the piss out of it!
are you familiar with what i'm talking about though? may not be the e-body(thats the charger/challenger right?) but the b-body (gtx/roadrunner/superbird?) i don't remember which chassis code goes to what, but I can assure you, the roadrunner/gtx/superbirds do it, in the same place. it make the door fit funny on the passenger side. these are rb and hemi cars
Good unibody info offered by Scooter and squablow. Once again, I have to ask Why? I can't see a single advantage to welding the cab to the frame.
I'm not familar with Jalopy43's car, but I think METALSHAPES unitized his because he wanted the extra stiffness of the body to help the handling of the car...but I believe he made some serious mod's to the body bracing to make it all work. Isn't his floor dropped down between the rails as well? Think it is...and I'm guessing its welded into the frame structure to act as almost a platform style frame that also resists twisting as it works with the high center tunnel and a stiff cowl/firewall/rear kickup. Thats how I'd approach it anyway...perhaps even to the point of adding a midplate mount to allow the engine block itself to add additional front stiffness to the frame. Consider though that the A body is covering 2/3's of the total frame and CAN add some extra stiffness in the rear easily, while the pickup cab is just in the middle. I think unitizing CAN work very well if the complete structure is planned properly and the car is being built with handling in mind, but if your just gonna weld it to make the assembly job a little easier...you might be disappointed with the drawbacks later on.
Oh yes...drawbacks would be potential squeeks, sheetmetal cracking, increased noise(LoL...I know!), limited access to components, rust caused by water entrapment...etc.
since you're thinking of adding a roll cage, welding the body is a damn good idea. I've had many unibody cars with the frames connected (welded frame rail inserts) thus making them full frame cars. Never really had any of the problems mentioned above. Doors always opened, windows never cracked and sheet metal stayed put. A box is still a box. Seems like it would have to be stronger. As far as the suspension goes, if it is working properly, there should be no trouble with twist or vibration.
Actually, if you ADD subframe connectors to a car thats already a factory unibody, your REDUCING bend stresses that the cars sheet metal was designed to accept. Thats why Drag and road course Unibody cars used them...to ease the stresses and prevent cracking.
Yes Tingler! I welded the sedan body to the frame. Lots of tack welds. I ALSO bolted it to the frame in 4 places,just in case a weld popped. It does make a stiffer'box",and I do have a cage welded to the frame,and tied into the body. I also welded the column drop to the steering tube,since the body doesn't flex seprately from the frame. If you make it solid, it WILL be solid. What's the matter,can"t take a little vibration,and noise?? ha ha ha . For the type of vehicle it is,just get it fairly square to the frame and WELD it.. like they said you will finish it sooner. I do check my welds,from time to time,just as I do making sure all the bolts are tight. Seeya soon!! Sparky
OK, I've unitbodied a few old frame/body cars. I'm also pretty hard core Mopar and have circle track race those unit body cars. I understand the flaws. There are some things you will need to do. If you thinking about doing a roll cage, diffinately do that first. I suspect that Willis cab is going to need reinforcing, it probably didn't have much to begin with. The absolute biggest problem with a unit body car is the twisting that results from motor torque and traction. Ever watch a Mopar drag car that was getting it done, the rear end would lift and the left front tire came off the ground first. That is an example of the death blow twist. The torque of the motor is trying to roll the motor over in the chassis. As a result, it is pulling the left frame rail up and pushing the right frame rail down. That force is transfered through the radiator support, the inner fenders, the firewall, the frame rails, the trans cross member, the rockers, the roof's A piller (windshield posts), along the outside roof edges, and the roof's C pillers (rear roof supports that are attached to the top of the wheel wells) the rear frame rails, the shock cross member, the tail pannel and the top ridge of the rear qarters. All of these parts on that unit body are reinforced structures. On the Mopar, the front hangers of the leaf springs are between the rear frame rail and the rockers with the front of the wheel well as a triangulation. This is one of the weak points in the Mopar unit body, and the RB and Hemi cars (and converts) have an extra boxing plate at both ends of the rockers to add in support. While the motor is trying to twist the car, the rear axle is trying to roll backwards in the chassis on leaf spring cars, and trying to roll forward on coil spring cars. The result is the rear wants to lift on leaf spring cars and it wants to drop on coil spring cars. In either case the rear end of the car is trying to twist in a different direction then the front. Unfortunately the same body structures are trying to prevent both things at the same time. Now, lets talk about your pickup. If you get traction and have some torque on hand, your truck has to endure the same things as the unit body car has to. The original truck frame was designed to allow the frame to twist when it went off road. Motor torque wasn't an issue they were concerned about, the frame would have twisted from the torque, (really, a 4 banger a torque monster?) not a big deal. Since the frame rails were in the neiborhood of 6" high, and tireswere pretty small, traction twisting of the rear frame wasn't much of an issue either. So you have modified your frame. You say it is tubing with welded in cross members, so it won't twist? Hate to break the news to you, it can and will still twist. Your frame is basicly a ladder style frame. (looks like a ladder laying on the floor.) Now you have the bottom of that unit body configuration. If you add a roll cage to that ladder, the area under the cage will resist twisting a lot more then the ends, but the ends can still twist, both radially and up or down. You need to add in forward and rearward kickers to the cage to stiffen the ends of the frame rails. Those forward and rearward kickers need to be tired together across the width of the frame also. All this and it can still twist, but it will be much stiffer then just the frame. Now, lets talk about your truck cab. Most truck cabs I've seen have reinforced support around the doors, windshield, and floors. Most have little support at the roof or the rear of the cab. Just wasn't needed for what they were designed to do. Welding the cab to your frame is going to do very little to stiffen the frame, and would likely result in a few extra rattles, a year or two down the road. If you added the cage, that would make a big difference to the stiffness of the frame, (not enough in my opinoin) and then you might as well weld on the cab, because you wouldn't be able to remove the cab afterwards anyway without cutting something apart. BTW the guy with the 250,000 mile 68 Charger: You probably have body cracks at the rear edge of the doors on the top of the quarter, right where the quarter window and door window bottom corners meet. There are also probably cracks at the bottom corners of the rear window, but you probably have rust holes there instead. I have also seen them crack at all 4 corners of the windshield and at the rockers at the bottom of the rear edge of the doors. Seen wrinkled quarters too. Funny thing, where these Mopars crack from abuse is usually where they rust. Likely they cracked first and then the rust started. Of course, if you car never got traction, you car may have escaped without these issues. Cars with the torque boxes or subframe connecters often survived these cracks also, unless they were really abused. Gene
I missed the post about putting in a cage. That changes things considerably. The cage will stiffen the chassis enough to eliminate the body flex issues. The cab will have little effect either way. Once you cage it the body is just decoration. I'd still rubber mount it, but I'm old. BTW I like your truck. I saw a willys wagon done in a similar fasion when I was 10 or 11. I think that was the start of the addiction!
50dodge4x4 gave some very good information. As far as welding the cab to the frame to add structure to the frame goes... that cab was not designed to take those kind of forces, at least of that magnitude. Therefore, I wouldn't expect to see any significant increase in the strength chassis just but welding the cab to it. In fact, you will probably create a situation where you will cause damage to the cab from absorbing the flex of the chassis. Any sharp corners or 90 degree weld joints will tend to crack.
My truck is similar to what you are building. I put an 8 point cage in it, tubes in the cab are punched through the floor, rear through the cab and front through the firewall. If I ever wanted to "remove" the cab, it would require cutting it to bits. Front mounts are what I had pre cage, bushing and a bolt, rear body mounts dissapeared when the cage went in, so, I "hung" the rear of the cab on the roll cage by welding in some gussets. Works for me, although it does make some interesting popping sounds sometimes when you go up a driveway at an angle.
weld it!everyone saying that because the ol' dodge's had stress cracks its a bad idea.??these cars did not even have a full frame.the rat has a full frame.it's not going to be a big deal.would you be upset that a rat rod with a chop and butched parts would have a 3 inch stress crack in the body?NO.I don't think it would crack anyway.the cab is alot shorter than a car is so the frame will still be able to flex a bit if need be.truck beds have been bolted on for years. no rubber.do you see the bed side splitting into? NO.wled it and be done with it.you know what you want do it.beside if you put rubber mounts on it,it will lift the truck up and inch and a half.we can't have that.lol
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