Build-up plan XJ to MJ

[TNT]

How about mounting them on the upper part of the spring on the bumpstop tower? Maybe then you could use a lower bumpstop extention with the stock bumpstop for the final stop. This way you wouldn't have to guess how far they will compress before stopping.

Just a thought... It might increase there rate also.

 

[Jeff 98XJ WI]

Man I love these threads. Since your talking MJ stuff here TNT... let me ask you a few things.

Your considering removing the factory control arm mounts? I looked at these and was pleasantly surprised by the beef! Part of me does not want to touch them and just use them. Yet I really want a midarm setup 3 link identical to Goatmans. What have you decided to do with those mounts? Are you willing to cut them off? I am wanting to use the prerunner inspiration on my new MJ too.

I did a little more stripping on my MJ carcass today and after the carpet was pulled, I got a good look at some of the extra beef the MJ gets as compared to an XJ. There is a heavy guage Hat of sorts directly over the frame rail on the inside of the cabin spot welded through the floor pan to the uniframe rail underneath. I also noted a heavy guage piece of steel sheet formed into a gusset of sorts extending from the frame rail hat to the door sill area with a matching gusset underneath going to the frame rail. There is another one of these in the rear corner of the cab underneath. They are so beefy I really don't want to remove them, but they are in the way of creating a high clearance replacement rocker. I'm not sure what I'm going to do. The frame rail is quite interesting too. The bottom continues flat from the crossmember area back beyond the cab back. It gets quite tall by the back of the cab. The floor pan rises some as it nears the back of the cab though. Oh, the extra piece that is bolted to the side of the frame rail for extra bolts into the crossmember is also bolted through a flange on the uniframe rail, the floor board, and the hat I mentioned before. It's going to require more study before deciding on a course of action for the rocker region. As for the MJ lower control arm mount reinforcement pieces, you used to be able to buy them separately and install them on XJ's. I've got a few friends who did that. Jeff

 

[TNT]

I did a little more stripping on my MJ carcass today and after the carpet was pulled, I got a good look at some of the extra beef the MJ gets as compared to an XJ. There is a heavy guage Hat of sorts directly over the frame rail on the inside of the cabin spot welded through the floor pan to the uniframe rail underneath. I also noted a heavy guage piece of steel sheet formed into a gusset of sorts extending from the frame rail hat to the door sill area with a matching gusset underneath going to the frame rail. There is another one of these in the rear corner of the cab underneath. They are so beefy I really don't want to remove them, but they are in the way of creating a high clearance replacement rocker. I'm not sure what I'm going to do. The frame rail is quite interesting too. The bottom continues flat from the crossmember area back beyond the cab back. It gets quite tall by the back of the cab. The floor pan rises some as it nears the back of the cab though. Oh, the extra piece that is bolted to the side of the frame rail for extra bolts into the crossmember is also bolted through a flange on the uniframe rail, the floor board, and the hat I mentioned before. It's going to require more study before deciding on a course of action for the rocker region. As for the MJ lower control arm mount reinforcement pieces, you used to be able to buy them separately and install them on XJ's. I've got a few friends who did that. Jeff

So whats the build up plan for your MJ?

 

[Lincoln]

I wouldn't want my to increase the rate. I let my shocks be the final stop after 3" of squish. They slow the axle down a lot before they bottom the shock and I almost never feel a hard bottom.

I can't remember what I told Goat, but I think for go fast stuff I would plan 3.5" or 4" of squish. Whatever he ended up with on the first try wasn't enough. I drive pretty slow so the 3" works pretty good for me.

Your idea is something to look into but I would mount them the easy was and give them a try. Goat and I run quite different spring rates and both of us are happy. I don't know what springs Cracker runs but he seems good with them too.

 

[Matt S.]

I did a little more stripping on my MJ carcass today and after the carpet was pulled, I got a good look at some of the extra beef the MJ gets as compared to an XJ. There is a heavy guage Hat of sorts directly over the frame rail on the inside of the cabin spot welded through the floor pan to the uniframe rail underneath. I also noted a heavy guage piece of steel sheet formed into a gusset of sorts extending from the frame rail hat to the door sill area with a matching gusset underneath going to the frame rail. There is another one of these in the rear corner of the cab underneath. They are so beefy I really don't want to remove them, but they are in the way of creating a high clearance replacement rocker. I'm not sure what I'm going to do. The frame rail is quite interesting too. The bottom continues flat from the crossmember area back beyond the cab back. It gets quite tall by the back of the cab. The floor pan rises some as it nears the back of the cab though. Oh, the extra piece that is bolted to the side of the frame rail for extra bolts into the crossmember is also bolted through a flange on the uniframe rail, the floor board, and the hat I mentioned before. It's going to require more study before deciding on a course of action for the rocker region. As for the MJ lower control arm mount reinforcement pieces, you used to be able to buy them separately and install them on XJ's. I've got a few friends who did that. Jeff

I have been looking at rocker possibilities as well. I have almost come to the desicion that I dont want to cut any part of the MJ up (maybe ditch the bed but not soon). I know I will be plating the frame rail simply for dent resistance and flat belly possibility. Did you notice how different the crossmember mounts? I have a feeling the rockers will wind up looking like toyota tube sliders that have a kick in them to help protect the bed (and provide a step) I really cant wait to get it on a rotissery to start analyzing it all.

 

[TNT]

I wouldn't want my to increase the rate. I let my shocks be the final stop after 3" of squish. They slow the axle down a lot before they bottom the shock and I almost never feel a hard bottom.

I can't remember what I told Goat, but I think for go fast stuff I would plan 3.5" or 4" of squish. Whatever he ended up with on the first try wasn't enough. I drive pretty slow so the 3" works pretty good for me.

Your idea is something to look into but I would mount them the easy was and give them a try. Goat and I run quite different spring rates and both of us are happy. I don't know what springs Cracker runs but he seems good with them too.

I just might but if I use my shock as the stop I would add the shock bumpstops Goat posted also. Just some added cushion for those real hard hits and they might just save a shock.

poly shock shaft bumps

 

[TNT]

I have been looking at rocker possibilities as well. I have almost come to the desicion that I dont want to cut any part of the MJ up (maybe ditch the bed but not soon). I know I will be plating the frame rail simply for dent resistance and flat belly possibility. Did you notice how different the crossmember mounts? I have a feeling the rockers will wind up looking like toyota tube sliders that have a kick in them to help protect the bed (and provide a step) I really cant wait to get it on a rotissery to start analyzing it all.

Maybe a rocker replacement boatside combo???

 

[Lincoln]

I just might but if I use my shock as the stop I would add the shock bumpstops Goat posted also. Just some added cushion for those real hard hits and they might just save a shock.

poly shock shaft bumps

Goat was telling me about those tonight. I'm trying to think of how I would set it up knowing I had a secondary soft bump.

I run cheap shocks and usually shafts turn blue and other shit goes wrong before I lose a seal. One of these days I'll invest in something good and if I continue running my current setup they will get shaft bumps. One of these days I'm going to redo my front suspension and I've been waiting for that before buying good shocks. My current shocks were put on early last year and have a handfull of trips on them and are already blued.

 

[Matt S.]

Maybe a rocker replacement boatside combo???

You know, I am not sure if I want to go that route right away. Possibly when I put it down for the 2 version of the build when I do the tube work and new bed (maybe). Right now I think I am going to be building "bolt" on MJ sliders and a rear bumper, with hope to sell them after the 2nd version of the MJ.



Farmer kinda taught me that why slide on something that protects nothing? I almost feel having a skin from a rocker replacement to the bottom of the frame rail is useless. Why slide when you could just have air there?


On those bumpstops, if your saying your getting 4" of compression under hard use, do you have odd street characteristics because of the lack of non bumpstop compression during normal usage?

 

[Lincoln]

There are usually tubes supporting the rail that make nice rock grabbers.

 

[TNT]

I'm just tossing out some different thoughts on having a smooth increase in spring rate from the bumpstops. Also having a positive stop to protect your shocks and keep your axle from being force further up than planed and hitting the oil pan or something. Air bumps are great but $$$$.

 

[Goatman]

On those bumpstops, if your saying your getting 4" of compression under hard use, do you have odd street characteristics because of the lack of non bumpstop compression during normal usage?

I know mine compress at least 3.5" and likely a little more. Street handling is normal. We only use a couple inches of up travel during normal street driving so the bumpstop doesn't even get used, unless we hit a big enough dip or pothole or something, and then the bumpstop works like it's supposed to. One nice effect of those super soft bumpstops is that they give a more progressive spring rate just like an air bump.

 

[Jeff 98XJ WI]

You know, I am not sure if I want to go that route right away. Possibly when I put it down for the 2 version of the build when I do the tube work and new bed (maybe). Right now I think I am going to be building "bolt" on MJ sliders and a rear bumper, with hope to sell them after the 2nd version of the MJ.



Farmer kinda taught me that why slide on something that protects nothing? I almost feel having a skin from a rocker replacement to the bottom of the frame rail is useless. Why slide when you could just have air there?

Upon looking at the MJ outside the frame rail and below the floor, it already has a couple angled pieces in there that I feel might get hooked on something. The XJ doesn't have anything there. So, unless you remove the braces (which look to be adding quite a bit of strength), there IS something there other than air. I see Captain Ron removed his at some point in his buggy build. In fact, he removed everything from the outside of the frame rail out.

I don't want to go that far as I want to keep the cab intact and the ability to run doors for the crappy weather we have here in the midwest. So what to do to get high clearance rockers that can slide on things and not get hung up?

Tim, I plan to replace my current XJ with the MJ. I have a set of axles I'm working on and the MJ carcass. I'm building a HP44 with 60 outers, 60 shafts, and a 35 spline ARB. In the rear, I'm building a full float HP 60. I have a 4l60E tranny with an Advance Adapters output with VSS and plan to mate that to a GM 5.3 engine. I hope to run a Klune 4:1 mated to a STAK Dana 300 replace a case. I also hope to put coil overs on the front and possibly a rear quarter elliptic. I've got a LONG way to go, but I'm picking away at it slowly. Jeff

 

[Jeff 98XJ WI]

Take a look here:

http://share.shutterfly.com/action/welcome?sid=8IbtGzVo3bMnC

for some pictures of the MJ floor pan, factory braces, and rocker panel area. Jeff

 

[TNT]

Take a look here:

http://share.shutterfly.com/action/welcome?sid=8IbtGzVo3bMnC

for some pictures of the MJ floor pan, factory braces, and rocker panel area. Jeff

They are nice and beefy but would sure hang up hard on a rock. I would at least add a 45 degree or more braces to the edges to keep the from hanging up as easy and act as a slider. If you replace the rockers and boatsided it the frame strength would surely increase. They sure beefed an MJ compared to an XJ....

 

[vetteboy]

Just another bumpstop idea...

I got these small rubber helper springs from Timbren.

It starts off at around 4" and goes down to about 1-5/8" inches when fully compressed. There are two they offer in this size and I got the stiffer ones...I don't have quite enough weight to squish them down all the way so I think the softer ones may have been a better choice. There's a metal sleeve at the top and the bottom is open, you just put a bolt up through it and it's done.

They were around $24 each, part number A520-75 from any dealer of Timbren products...A520-65 is the softer version. I'm pretty happy with them so far.

 

[vetteboy]

While we're on the subject, Daystar has a new product that I think should work very well. No matter what you're running, I would go buy these right now.

poly shock shaft bumps

I have shaft bumps on the coilovers on the buggy, but being able to get shaft bumps on any shock is a great idea.

In the video, they only show them being installed over a stud-type mount...can these still be used over an eye/eye type of shock?

Might be a neat alternative for the front of mine, rather than the stack of hockey pucks I was going to use...

 

[Onkover]

The vid say that they can be used on eye to eye shocks also. I assue that you have to have rebuildable shocks though... just my assumption

 

[vetteboy]

I watched the video with no sound, so that might be my bad. I have Bilstein 5125's so if there's any shock that should be adaptable, I'd imagine those are...

 

[Goatman]

There is an intallation tool listed for eye to eye shocks as well as stud mount. I'm getting a set for my rear 5150's......maybe the front 7100's.