Here's one for the experts. Background; I am a mechanic/ machinist and a fair welder. I have a 68 Jeepster Commando with serious modifications including a 455 cid buick engine. My frame cracked and I have a spare without cracks. The stock frame is fully boxed, but is only about 4 inch. I have aquired a 74 Wagoneer, and am planing on using the running gear from it. I have decided it would be better to use the Waggy frame, as it is 6+ inch and thicker, and I won't have to build as much onto it.. It is only boxed about 1/3 of the way from the front, and I have another Waggy frame which could be cut up to provide sections to fully box this frame. It wasn't designed to crawl over boulders. The main question is, is it wise to box it to make it more rigid, or let it flex as designed?
Do you want it to ride like a 4x4 plank sled on ice? Do you expect that a big motor in a small frame will have any longevity? What kinds of terrain will you be driving over? How hard will you drive it? Is high speed handling an issue? How often do you want to change the frame? Are you willing to bet your life on this?
Anyone can put a big engine in anything. After that, Darwinism takes over.
post up on pirate4x4 for some more specific answers and experience. If it were me I would realized that you are using this for something that it was not designed for from the factory. Your new design needs to incorporate strength, so you need to make it strong. I vote that you need to box in the entire frame, and make it as strong as you can without unreasonable weight added. If I were to sit down and make a frame from scratch I would not question using a fully boxed frame. Also look for other stress points and add what you feel you need to them to beef them up as well, things such as the spring mounts that are so common to get torn off or damaged.
Thanks. I was looking more for the "engineerist's" viewpoint, most of the guys on the Pirate board are either kids or mechanically declined and seem to think throwing money at a problem is a good solution. There are some good guys there, too, but you have to wade thru a lot of dreck to find them. My old frame took a good 15 years of rough use before metal fatigue got serious, and on a cost per mile basis it did pretty good.
I agree about your comments about pirate. There is some good info, but you have to do a lot of wading through a lot of $hit before you get to the good stuff. I don't know if I have the answers you are looking for, but maybe someone else will chime in and offer more help. Your final plan is to run the waggy heavier 6" frame, the Commando body, the waggy d44 axles, and a
300+ HP engine? Did I follow you right on that? And how will it be driven? More of a family / trail ride machine? Or a hard core lets see what breaks this time rig?
My initial feeling is that either way you will be ok with the waggy frame. I think that they are heavy enough and stiff enough that you can probably use it as it sits now. You got 15 years out of your old frame, this one should be stronger than the first so I would guess you will get 15+ years out of your new frame.
I also think that the rockcrawl scene is going to be harder on frame as far as twisting and bending than they were originally designed for. I would error on the side of over building and adding strength to the frame with the idea that the intended design for flex is going to be exceeded and you need to add strength to reduce some flex. I would think that boxing the frame would be the way to go, and maybe adding some strap in key spots.
Do you know if your waggy frame is heat treated? That may add into the equation as well. Not sure if I would feel better about a heat treated stock frame, or a modified frame that has lost it heat treatment by welding all over it.
One more suggestion may be to visit the Hobart forum at
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they are welders with an off-road section. Look for one of the guys there that built his own frame from scratch, I liked what he had done.
In the meantime I will watch this thread to see if anyone else has any input. Good luck
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