frame welding

[crownvicjim]

if i cut my 89 crown vic frame in two and shorten the frame will the frame be strong enough at the welds? will it flex at these points more? i am having a hard time finding a real answer to this Any Help???

[mike@af]

It depends how good of a welder you are. If I were to weld it back together I would TIG weld it because the welds have more penetration and they are the strongest. However, its not the equipment that makes a good weld its the operator. If you are only a decent welder, or are unsure of your weld's strength, dont risk it.

Dont forget to put in some triangulated reinforcement. And arent those cars unibodys?

[Devious Designs]

If you need to ask for advice on a project of this caliber, then your probably not qualified to do it. Because no matter what someone tells you on the Internet... it can't beat past experience, especially with something as critical as the frame. Mike I disagree with you though a MIG can properly weld a frame. I cut and made a 8" notch in my rear frame (s10) to clear the 18's when aired out, and basically had to cut the frame apart and reweld. Granted I had a millermatic 210 and I've done this type of work before, but you gotta remember most frames aren't that thick, my s10 is less than .25, hell the notch was thicker than the frame at about 3/8 lol. Just make sure you get the penetration nice and deep!

[mike@af]

Brook, I never said you couldnt MIG weld the frame back together. I was just saying that I would prefer TIG. I've MIG welded many structural items before with no problem...but I would have prefered TIG.

[crownvicjim]

i have to some other guys on this and they said 2" x 2" square tubing will fit snugly inside my frame. he said to add about a 2' section inside each rail and drill hole thro the existing frame to get to the 2x2 tubing and weld each of the drill holes. i am a novice but i am going to do this anyway. i know it is retarded but without a job in this field how would u ever get the experience necessary. my only welding experience is for a well drilling company for a year and i never had any problems there. i think shortening the body is gonna be a helluva lot more difficult than the frame!how will i judge how much to take off of the driveshaft? because of the angle im sure it will be a different measurement than the 16" im cutting off the frame and body? triangulated reinforcements?(extra crossmembers?)

thanks guys i will email pics if u want when all gets started

[mike@af]

Let me go ahead and say this now. The frame absorbs thousands of pounds of shock on it. Shear shock, impact shock, elastic shock and so forth. You need to take some of welding classes before welding something that needs support. I cannot stress enough how much shock the frame takes.

Plus you dont seem to undestand the logic behind half the stuff you mentioned or posted, therefore you need even more classes on the ideas you propose. Designing/fabricating frame stuff is no easy cut and weld job. There are certain stress points where triangulation is needed, as well as build a jig that is better than the frame.

Experience is something you get through mentors and classes, classes and classes. Im sure I could weld up a frame myself, but I have a foggy question in my mind there for I am not going to put other peoples life and my life in jeapordy.

I hope you heed my advice. Let the professionals do what they are trained to do.

[crownvicjim]

i appreciate your advice . i am still going to do this . i am just going to plan it out better . if i have to pay someone to do parts of it i will. a rollcage will be made (not by me) this will add integrity to the frame(yes?) there are going to be measures taken to ensure that it will not endanger me or anyone else. i want it to be safe. how would you suggest to make the frame more rigid and durable ? sorry if u disagree but i am going to complete my plans and it would be nice if you could helpme wiht some stuff to take into consideration so it will be done safely thanks GT

[mike@af]

Jim. I suggest putting in a bunch of triangulation around the spliced area. Also, if you can, put in reinforcement in the frame to join the two pieces together better. When the rollcage is built, make sure they build it on the frame, rather than to the body. To keep things strong, make as few cuts as possible.

[Devious Designs]

Are you sectioning the body? Is that why you want to cut the frame to match? If your sectioning a reasonable amount you shouldn't have to touch the frame. I don't quite understand what your trying to do, but putting 2x2 box over your existing frame is a joke, yeah it'll probably work, but if I saw it at a show I'd laugh at you.

Depending on how far back you cut on the frames, I'd just add 3x3 box from that point back. Again I have no idea what your trying to accomplish here and don't know where your planning to cut. As for the driveshaft, are you serious? Do you really think YOU can shorten a driveshaft? It would be much more logical to find a shorter driveshaft than try to salvage the old one. Honestly it sounds like you have bigger goals than you have talent for, so its either going to come out like junk, or your gonna pay someone alot of money to do it! Just my .02Cents

Oh btw, Mike I hope you don't mind, but I couldn't figure out how to post pictures on the forum, so If you pm your email adress, I'll send you some pictures of a backhalf I worked on that is perfect for this frame question.

Thanks, Steve

[duplox]

I don't think he was implying he was going to shorten the driveshaft himself. He just wanted to know how to calculate how much to shorten it. While the driveshaft is not at the same angle as the framerails, the driveshaft has a slip yolk so it has room to move around, so the measurement doesnt have to be dead on. The difference in angle is very slight. Just shorten the driveshaft the same length. In a lifted truck application where the driveshaft angle is huge, you'd need to run calculations, but in a car where the driveshaft is only a few degrees off the frame, its not really neccesary. Although to be sure, I'd do some simple pythagorean theorum math just to see the difference. I ran a simple calculation off the top of my head. I put the trans output 48" away from the differential input, measuring parallel to the frame. I put the diff input 12" below the trans output. 12" is a bit excessive I think, it'd probably be close with the suspension fully unsprung. Using these numbers, I got a driveshaft length of 49.48". As you can see, the driveshaft length is nearly the same as the horizontal distance(frame length) between the trans and rear axle. So shortening the frame length 6" would logically shorten driveshaft length pretty much the same ammount. But lets run the calcs anyways. Putting all the numbers in again, except using 42" instead of 48", we get a driveshaft length of 43.68". Shortening the frame 6" shortened driveshaft length 5.8". Very close, considering the slip yolk allows for around 5 or 6" of play. I'd suggest running these simple calcs just to be sure. It only takes a couple minutes.. If you want more details on how to do it, I can give them.

As for the frame shortening technique, I think you're misunderstanding what he's saying, Devious Designs. I believe what he's planning on doing is cut the frame, remove however much he wants to, drilling a few holes in the side of the frame near the joint, put a section of square tubing inside the frame(not outside), and sliding it all together, then welding the frame back together, and welding the drilled holes to the square tubing he put inside. Just extra reinforcement. If done well you shouldn't be able to tell there is anything inside, nor that the frame was ever cut at that point.

[goinbig]

Box in the frame (the entire frame if you want to do it right) and you should be good to go.

But, I would make sure you know what you're doing before you start. Things like shortening the driveshaft should not be a big deal at all if you knew what you were doing....which is why I think this might be a bad idea for you to go through with!

[weldreality]

All auto / truck frames are welded with ease, and welded with commom E70S-3 OR 6 MIG weld wires. As many of you are aware, many frames are a welding mess thanks to a lack of process controls from the big three and their tier one suppliers. Your welds if made correctly will simply take the weld quality up a notch.. For more info visit the worlds largest web site on MIG welding www.weldreality.com

Ed

[TheSilentChamber]

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