2X4 frame for my CJ2A

Yes, this makes sense. My wheel well is going to get oversized as the tires will not fit as it is. The front is a different story as most of the weight of the drivetrain is on it. Once I locate the engine i can adjust that. I will probably just throw the transmission/transfer case in the body to simulate weight at that point. All the suspension is just tacked. Aside from the frame rails, all of it is still in mock up stage.

These springs are a matched set from some guy whose wrangler and its 4 cylinder couldn't turn his tires in OD and had trouble in just high gear. 4" lift, never see flat. got the whole set with shocks under 100 bucks.

You guys have obviously done this more than once. I appreciate your input. I am pleased with how this is going so far frame wise.

 

I thought that a shackle reversal up front would do MORE to help on road driving than it would for off road driving. Maybe I am confused. I thought it helped on road stability and handling characteristics.

 

I have neve done this mod, nor have I driven a rig with the shackle reversal. Everything I have read states that this mod is fine to do, but will hurt on road stability. I may very well be wrong, but thats just what i read. I would appreciate it if others would chime in on this.

I am in process of engine placement. I will most likely need to use 1" body life as chuck has suggested. I am running the cj5 headman headers. I really don't think the are optimal for placement in a cj2a, but they are relatively inexpensive. I have been running the thick 3" or so fan spacer with a 17" fan from a buick. I realized that I might do better with a thinner fan spacer. Lo and behold one of my dauntless fans had a 1/2" thick spacer for the fan. Unfortunately the fan is 15 inches. I am probably going electric fan anyway, but if i want to go cheap I will just separate the thin spacer and use the bigger buick fan.

I actually felt bad for cutting up my old frame for the old motor mounts I fabbed up. Like i will ever use it for anything but scrap. I did a good job on those and I think I will just reuse them. I Don't think I need to offset the engine to clear steering and actually am more concerned with the oil filter as it is directly beside the frame rail. With engine centered it has plenty of clearance.

pics tomorrow.

 

Just the opposite.........Ride is said to improve in either case.......it's the stopping that can get you in trouble on the pavement via axle wrap and bump steer when braking. The engineers from Jeep seem to agree on that placement.

 

Thanks for the clarification Tarry! Anyone else out there run a stock m38A1? Do their own shackle reversal? How did it handle on road? Braking and bump steer and did it make a big difference compared to the shackles up front? I remember this being a go to mod in the 90"s and I always thought i would do this.

Most likely I will be cutting off the mounts on one end or another on both ends again to get the suspension right anyway, so if I get a convincing argument on why I should do this It wont be a big deal.

 

For what it is worth, I have driven friend's rig, both on highway and off road, with reverse shackles on it and honestly could tell any difference in the ride. I was originally planning on doing this myself until I drove my friend's jeep. In fact there were things about the way his jeep drove I absolutely didn't like, like the way the nose dove when braking as the axle movement exaggerated the weight transfer. Not fun on the highway or going down steep hills

I think with our such a short wheel bases it doesn't really make a hoot of difference smoothing out the ride... thus why Landcruisers, Land Rovers, Suzuki Samurais and even the Jeep Wranglers still have the shackles in front. If all it took to smooth the ride out was putting the shackles at the rear of the spring these manufactures would have done so long ago. Other negatives with reversing the shackles is that the axle swing can limit the room for larger oil pans when doing engine swaps.

So in the end, I decided not to do it myself.

 

Well that pretty much settles that for me.

I have mocked up the engine. Mounts are in place and I will tack em in a hot minute. One thing, the cj5 headers are kind of lame in a 2A. They just don't fit the way I want them to. They go outside the frame rail too far and make it a PITA to deal with. Since I don't have a bunch of money to spend, I will deal with them. I know there are options, just not cheap options, I have these, they work and I will be using them.



The engine it as far forward as I want to go. It is also as high up in the frame as I can make it and still clear the hood with the air cleaner. Right now I have a shorter air cleaner and with the extra inch of body lift I plan on adding, I should be able to fit a full size one if I choose to do so. I can run a steel fan with the short spacer or mount an electric fan in front of the rad or behind in the future.

Look, its a Blueick engine!

 

Chris..........is that still primarily a Street vehicle?.........The shackle reversal also adds another issue with your drive shaft and slip yoke , moves just the opposite as a conventional system as the suspension goes into compression , length is all important a different drive shaft will be needed.

If ride is the concern then thinking along the lines of a longer flatter spring package is the direction you want to go in that is of course matched to the weight it's supporting. Stay away from anything that has a high short Arc.

 

Terry, this is primarily a street vehicle. I do abut 1% off road with it. Sure would like to do a lot more off road and certainly with what i am doing this will happen. The driveshaft length is going to change as I have moved my engine placement. I will have to adjust them and or make new ones. The driveshaft and shackle reversal is not something I actually thought about. I am not going to do it, but it is something that others who look at this thread and are contemplating this reversal may need to think about.

As far as ride is concerned, its a jeep. I am using the rough stuff mounts for spring and shackle you sold me and the suspension already works better than it did with my home made mounts that seemed to bind the springs a bit.

Thanks!

 

I'm glad the mounts are working for you.......make sure you use some lube...........On the springs I would much rather be under-sprung a little rather than over.

 

I've done a shackle reversal on an early CJ5 with stock springs, a 3B with sprung-over YJ springs, a Willys PU on a Scout frame, and a '74 Scout, both with SOA YJ springs.

I did this in all my competition rigs because I was going through spring packs like crazy with the standard setup. In the standard configuration, the axle's natural arc of travel is up/forward, with the arc's radius traveling around the frame mounted spring eye in the rear. When you hit a bump or rock, it naturally wants to travel rearward, not forward like it is being forced to do. Go hard and fast against an immovable object and you end up with the main leaf with a permenant bend in it, about 4" in from the rear mount. Doing a SR changes that arc's pivot to the front, and you have a much more natural, less jarring movement of the front axle. It improves traction because the axle can travel backward while the vehicle is still moving. The standard setup requires the axle to move forward unnaturally as the springs compress.

I've personally never noticed a difference in braking.

What I've found is that the #1 issue with a SR is that when going up a hill or over a high obstacle and the springs unload when the weight transfers to the rear, the axle wants to (A) walk out from under itself due to the action/reaction of the torque of the wheel going forward, forcing the equal amount of twist on the axle and springs in the opposite direction. The pivot in the front and shackles in the rear allow this movement to happen. This axle twist also causes (B) the pinion to twist down toward the ground, placing an even greater strain on the already tight u-joint angle. A & B together are the cause of the massive amount of slip-yoke travel needed for a SR, especially with a long-travel setup. I typically use endless-travel PTO parts from the tractor store for my front driveshafts. Factory splines just aren't long enough.

The #2 issue I've come across is death wobble. It was a noticeable difference - but not too much of an issue - in my Scout frames, and I've managed to get it under control in my 3B, but that 5 was awful. The theory I've come up with... and this is just my thoery... is that even in a perfect, fresh leaf spring setup, there is always going to be a bit of side-to-side "swing" in the shackles. With a traditional setup, the steering control is between the axle and the swing (the shackles up front), and the hard mount is keeping the rear end under control. When this swing is on the far side of the axle and steering controls, I believe it just puts too much axial leverage on the shackles for them to be able to keep everything from flopping around with the slightest bump in the road. The narrow spring width and inherently weak spring bushings on the CJ5 only added to its issues.

For a primarily off-road rig, I think the benefits definitely outweigh the drawbacks, but for a street rig, I honestly don't see the point.


Disclaimer: The preceding mosly applies to leaf springs that have a positive arch. Springs that have zero, or a negative arch may fall under different rules

 

I won't hijack your thread with pics, so here are some links if anyone is interested.

Square PTO shaft: http://i1280.photobucket.com/albums/a481/FCWoodworking/Mobile Uploads/image_zpslyie98sp.jpeg

SR on the 3B:
http://i1280.photobucket.com/albums/a481/FCWoodworking/Mobile Uploads/image_zpsv7haitmy.jpeg

Close-up of the through-frame shackle mount. Note the rub-plates I put on the frame to help prevent the "swing" of the shackles. This virtually eliminated death wobble.
http://i1280.photobucket.com/albums/a481/FCWoodworking/Mobile Uploads/image_zpscyol9nfn.jpeg

 

Im going to hijack my own thread with a pic of a new engine mount.

not the best TIG welder but I get it done. I would have mig welded the spacer but that machine is outside in the rain covered up. Didn't have the right tube, so i made it out of solid round stock on my lathe. Not the best economy of time, but its done.

 

this is totally safe


I gotta say I was irritated as all heck with how this was all going together today. Pushed the engine forward an inch to get better clearance for the headers and succeeded in messing up the hole in the body for the shift tower, transmission cover don't fit no more and the headers still fit like poo. They are made for a cj5 not a cj2a. Really have to have at least a 1" body lift no matter what. I did all this on my last iteration and somehow thought that I could do better, well with what i have its going to be a similar fit. My real issue was that the passenger header tube would rub on the body a bit before. I really must fix that or I will go a bit more crazy for sure. Hate buzzes, rattles and the occasional doinks. Scooby doo sound effect jeep?

yes, i know the front shackle angle is so not right. I though that with the weight of the engine it would get right. Nope. gonna have to cut off the spring mount and push it forward an inch or so.

 

fixed front shackle angle today. Tacked in the motor mounts for the second time and cut them out. I then tacked them in a third time. i think they will be ok where they are now. The engine is offset about 1.5 inches to the DRIVERS side. There is still plenty of room for steering and whatnot. The real problem and one that irritates the heck out of me is working with the CJ5 headers in the CJ2A body. They just aren't the right thing. I made them work before and they will work again but they just aren't ideal.

The body must have a minimum of 1" lift.

http://www.novak-adapt.com/catalog/headers/buick-90-degree-v6-headers/
These might work but require a lot of real exhaust work and they are expensive. I know some of you guys have done other things.

The idea behind the CJ5 headers is relatively cheap fast and easy. I could probably cut out 4" out of the tube on those and weld them back together but they are already rusty as heck. Even painted them with high temp paint.

I have a set of buick cast manifolds that exit rearward. Once again this requires a lot of work to get around the CJ5 headers.

I have to leave for work and won't be back to do jeep work before next tuesday, so everything is covered in the car port and all cleaned up.

 

Been busy with life, so jeep had to wait. I have had an hour or 2 here or there. cut out a motor mount for the 4th time to make it right. i think it is ok, cut off all the body mounts and re tacked them an inch and a quarter higher. cut off the rear bumper and raised that up an inch and a quarter higher, cut off the rear shackle and spring mounts that were on that bumper and then fixed the shackle angle. gotta make the stand offs for the grill again as they are now too short.

today in between rain I am mocking up the saginaw gear. I am doing that so I can cut off the cross member the shaft has to go through, saw out the hole, insert pipe and weld.

I am using the mount plate I fabbed up for my old frame. i cut it off and it will work fine. Its made out of 3/8 plate. The bottom has 3/8 doubled to compensate for the setback of the saginaw gear mount points.

I dont know the correct way to orient the drag link, so i am just trying to keep it as straight as possible without interference with the tie rod. I have read that this is a way to prevent bump steer.

I could go up with the steering gear and mount it proud of the top frame rail, but I don't know that its required. You tell me.

 

The pitman arm looks straight and the short tie rod angle looks good where it is at right now.
If the Saginaw box is moved higher then that will only increase "bump steer".
Was you planning a tie rod flip ?
If so do it now.
You may want to add the body or simulate the correct gross vehicle weight.

 

I'd get the box as close as you think it should be and just tack it on for now. You can always fine tune its location after all the weight is on the rig. You want the drag link and tie rods as close to parallel as possible when finished. Since you can always get a pitman arm with less of a bend (and not more), you might want to start out a little lower. If you end up too low, you can grab a pitman arm from a junkyard with less of a bend. Less pitman arm offset also puts less strain on your box and mount.

Mounting it lower might simplify your hole through the crossmember, too. You could just do a half-moon on the bottom of the tube, then that wouldn't limit your location if you had to move it lower later.

Man, you don't have much turning radius with those 35s, do you?