Yj coil conversion

a_kelley

a_kelley

mechanical fixer
Joined
Jan 26, 2010
Location
Rutherfordton
I've got a 87 yj, planning to swap a xj front end under it(among other things), maybe a zj rear (yeah it's a 35 but it's free.. Other option is a xj 35)

I was pondering if the lower control arms might bolt into the rear spring hanger on the front and add UCA hanger and spring mounts.. Yeah, I know I could get a tj for less than the work I'll have in it.. Other thoughts were land Rover radius arms (free as well) or a three link.
 
Best solution if you plan on wheeling it would be a 3 link get a whole kit from barnes4wd and build it and never look back


I'd also add a truss and new axle trackbar mount. I used artec truss system it all works great. If you don't plan on keeping the 30 for long then don't do it, its kinda expensive lol
 
I was more shooting for just a small (3-6") lift & better ride.. Really have no practical use for a wrangler. Might just be better off to take what I want off it and sell the rest but the part of me that likes resurrecting stuff said I should keep it. Ask the few trash neons I restored and lost money on.
 
a_kelley said:
I was more shooting for just a small (3-6") lift & better ride.. Really have no practical use for a wrangler. Might just be better off to take what I want off it and sell the rest but the part of me that likes resurrecting stuff said I should keep it. Ask the few trash neons I restored and lost money on.
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Imo, if you have no practical use for it, you are wasting your time and money. You really aren't gaining anything from what you are trying to do. If you wanted to swap to coils in as a prerequisite to swapping in larger axles later, I could possibly see it.
 
justjeepin86 said:
You really aren't gaining anything from what you are trying to do. If you wanted to swap to coils in as a prerequisite to swapping in larger axles later, I could possibly see it.
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So a quadralink suspension or radius arms ride no better than leafs? My wife had a yj before and I thought it rode like crap.. Could be the wheel base difference there too. So yeah, no practical value, but does a resto-mod have practical value other than to improve something you like for yourself? 1461667567426313505390.jpg
 
justjeepin86 said:
Imo, if you have no practical use for it, you are wasting your time and money. You really aren't gaining anything from what you are trying to do. If you wanted to swap to coils in as a prerequisite to swapping in larger axles later, I could possibly see it.
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This x2.

You can get it to ride better with waggy springs.

My yj rode tons better when I installed my rough country lift kit and shackle reversal. It was a night and day difference in ride quality.
 
^^^^what this guy said^^^^ Only reason I switched from leafs to links was too much wheel hopping and almost knocking the front spring hangers off at Gulches on four foot tall rocks
 
I have to disagree here. The coil suspension is a magnitude better than a leaf setup. I guess the amount of gain will depend on what your planing to do with the Jeep.

In order of applicability from street use to offroad use...

The leaf ride isnt even comparable to a coil ride.
Road manners are way better. Road feel, handling in general are far better
The elimination of the axle wrap alone is worth the effort
The flex that can be designed in is so far superior than a leaf.
The flexibility of future axle/wheelbase/link changes arent even a factor with leafs
Approach and departure angles waaaay better
The forward bite that can be designed into a coil/link setup is a magnatude better than a leaf.

Leafs have one saving grace. They are durable. That's why about the only thing still using them are dump trucks!
 
ol'Jeeps said:
I have to disagree here. The coil suspension is a magnitude better than a leaf setup. I guess the amount of gain will depend on what your planing to do with the Jeep.

In order of applicability from street use to offroad use...

The leaf ride isnt even comparable to a coil ride.
Road manners are way better. Road feel, handling in general are far better
The elimination of the axle wrap alone is worth the effort
The flex that can be designed in is so far superior than a leaf.
The flexibility of future axle/wheelbase/link changes arent even a factor with leafs
Approach and departure angles waaaay better
The forward bite that can be designed into a coil/link setup is a magnatude better than a leaf.

Leafs have one saving grace. They are durable. That's why about the only thing still using them are dump trucks!
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I agree that coils are superior in most aspects and it sure as hell would ride better. My thoughts were more about what the OP said. I thought it would be a lot more work than it's worth for him. I 3-linked the front of my YJ when I had it. But it was to put a full width 44 and 36's on it. If he has the parts and the time, whatever floats his boat. As long as he has the skill to do it without killing himself or someone else.

And we never answered the original question either. I have seen lowers bolted into factory spring hangers. They are pretty short that way and would not give you as good of a ride as adding different mounts farther back and increasing the arms length. I'm not sure if the factory XJ arms are the length to get you there or not. Someone else would have to chime in on that one.
 
Download the 4 link and 3 link calculator.

Put the locations of where you imagine the links to be in the calculator and post up what your findings are.

Shoot for 50 to 80 percent antisquat and antidive, less that 1 degree roll axis angle, get your roll axis heights as close to the COG height as possible to minimize body roll.

Get your numbers to stay true throughout the travel range.

There is no reason to fab up a link suspension and not get the geometry correct.

Ride quality is dependant upon spring rate, shock valving, and suspension geometry. Any of the three way far off and any fix is a band aid.
 
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I'll do that with the calculator and post up. Yes, I can lay a decent bead. I built my bumpers with hitches and haven't seen any cracks in my welds develop yet and that was like seven years ago.
 
So for those interested, stock xj lowers are 16" c-c (give or take), 17.5" from axle tube to bolt at level height. Yj is 20.5" from axle tube to leaf spring bolt at level height. Short of long is that xj lowers will not just bolt in without pulling the axle back about 3" (or moving lower CA mount forward. As well, the spring would have to sit under the frame(yj frame at axle is wider than xj at the axle), with stock xj springs would be 5.5" lift or so (assuming front weight of xj & yj is similar). So I shall answer my own question, No the lowers won't bolt in. Can it be done? Sure, longer links than the xj. It'll be a few weeks before I post up my links (paying work interferes with my desires to fab). That or I could move the mount forward but I'd rather lengthen the arms that few inches, and no I'm not welding two stockers together, although it may end up bushing instead of JJ or heims since it will be parts runner/street/trail ride.
 
a_kelley said:
So for those interested, stock xj lowers are 16" c-c (give or take), 17.5" from axle tube to bolt at level height. Yj is 20.5" from axle tube to leaf spring bolt at level height. Short of long is that xj lowers will not just bolt in without pulling the axle back about 3" (or moving lower CA mount forward. As well, the spring would have to sit under the frame(yj frame at axle is wider than xj at the axle), with stock xj springs would be 5.5" lift or so (assuming front weight of xj & yj is similar). So I shall answer my own question, No the lowers won't bolt in. Can it be done? Sure, longer links than the xj. It'll be a few weeks before I post up my links (paying work interferes with my desires to fab). That or I could move the mount forward but I'd rather lengthen the arms that few inches, and no I'm not welding two stockers together, although it may end up bushing instead of JJ or heims since it will be parts runner/street/trail ride.
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This is the reasoning behind my last post. There is no reason to fab up a 4link and not get the geometry close.

You can design everything for free, just takes some time and a tape measure.

Then you can buy all the parts when you can, and build it to match your design.

This way you aren't in a hurry to do either, and no corners are cut.
 
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