Coil springs & radius arms for d350 to w350 conversion

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Coil springs & radius arms for d350 to w350 conversion

Postby liftarc » Sat Nov 18, 2017 7:13 pm

I have a 92 D350, already swapped in a g360/np205 on a stock 4wd trans x-member to replace the original auto. Rear has factory 6" blocks and longer rear driveshaft, good for now.

For the front Ive been cooking up a plan to keep the 2wd engine x-member, leave the coil springs in place, fab radius arms and mounts, and of course add spring buckets to the d60.

By placing the axle under the 2wd coils, I would gain plenty of height, minimize downtime and cost, and hopefully have better ride quality than stock leaf springs. I want to prefab my mounts and arms and have it ready to go so I can do the actual conversion while Im home between jobs. The axle is tore down for rebuild so I plan to do all the needed modifications before its rebuilt and painted.

My goals are to have a comfortable and capable daily driver that can haul at least what the truck is rated for, get my 4wd functional with as little actual downtime as possible and to keep costs low. Im not building an offroader, just need to get my tools and trailer to jobsites through snow mud etc. I don't care much about adding lots of suspension travel or articulation, I have my Ramcharger for wheeling.

I am totally comfortable doing the fab work but I need help with the tech side, parts selection, suspension geometry and Im happy to take any advice.

Thoughts?
92 D350 club cab flatbed dually-201k G360, NP205,D60 swap soon
92 Ramcharger 5.9 Magnum, 46rh, NP241-238k
liftarc
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Re: Coil springs & radius arms for d350 to w350 conversion

Postby liftarc » Sat Nov 18, 2017 8:21 pm

@#$% photobucket for screwing forum based research....
92 D350 club cab flatbed dually-201k G360, NP205,D60 swap soon
92 Ramcharger 5.9 Magnum, 46rh, NP241-238k
liftarc
fuel screw!!!!
 
Posts: 94
Joined: Thu Mar 03, 2016 1:28 pm
Location: State of Jefferson

Re: Coil springs & radius arms for d350 to w350 conversion

Postby RedRam » Sun Nov 19, 2017 7:15 pm

This is a great idea. I think that you would want an adjustable length track bar and have the caster angle adjustable at the lower radius arm mounts.
I have a crossover steering setup from NW Fab in Canada, probably my single favourite upgrade to my truck. Steers like a new truck.
1992 w250 ext cab a518, 4.10, bd fuel pin/spring, BHAF, 4" exhaust, parabolic springs, 33" duratracs
1990 w250 reg cab new project
2016 cclb 6.7 g56 laramie, levelled, 325/65/18 duratracs
RedRam
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Re: Coil springs & radius arms for d350 to w350 conversion

Postby liftarc » Mon Nov 20, 2017 10:48 pm

RedRam wrote:This is a great idea. I think that you would want an adjustable length track bar and have the caster angle adjustable at the lower radius arm mounts.
I have a crossover steering setup from NW Fab in Canada, probably my single favourite upgrade to my truck. Steers like a new truck.


Why do you suggest making the adjustment point at the lower radius arm mount? I planned to make it adjust at the upper mounting point like Ive seen and I prefer that hardware on top of the arm where its more protected. This would be caster angle right?
92 D350 club cab flatbed dually-201k G360, NP205,D60 swap soon
92 Ramcharger 5.9 Magnum, 46rh, NP241-238k
liftarc
fuel screw!!!!
 
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Joined: Thu Mar 03, 2016 1:28 pm
Location: State of Jefferson
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Re: Coil springs & radius arms for d350 to w350 conversion

Postby RedRam » Wed Nov 22, 2017 8:15 pm

Either way would work if it means your axle ends up where you want it.
What I like about the bottom adjust - the axle moves forward or backward slightly when you rotate it with the adjuster to change the caster with either setup. When you lift a radius arm truck the axle moves rearward, and you also lose caster. By restoring the caster with the bottom adjuster it also rotates the axle forward again into the center of the wheel well (in thoery). If you were using a top adjuster you would be pulling the axle back further when you correct the caster.

The reason all of this may be important is that there is a good possibility that having more positive caster may a cure for stability issues (wobble) with solid axles, and nothing beats having and nice straight tracking front axle. Or at least nothing worse than the opposite.
If you're interested in more potentially useless info in the subject I have plenty, especially if you're building this for off road use.
1992 w250 ext cab a518, 4.10, bd fuel pin/spring, BHAF, 4" exhaust, parabolic springs, 33" duratracs
1990 w250 reg cab new project
2016 cclb 6.7 g56 laramie, levelled, 325/65/18 duratracs
RedRam
smoke screw?
 
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Re: Coil springs & radius arms for d350 to w350 conversion

Postby RXT » Fri Apr 06, 2018 8:41 pm

liftarc wrote:Thoughts?


Yeah, I hope this isn't too lateā€¦.so, beginning with your quote;

For the front Ive been cooking up a plan to keep the 2wd engine x-member, leave the coil springs in place, fab radius arms and mounts, and of course add spring buckets to the d60.


The 2wd X member is a large piece thats designed to carry the weight of the vehicle via the suspension normally attached to it. Keeping it will mean you might have a clearance problem between the x-member and the front axle, especially the differential. The only option to keep the x-member and use that axle is a bunch of lift.

As for using the coil springs, yes you'll need to build spring buckets, but also brackets to mount up the radius arms. The big concern is the width of the axle. It has to be wide enough and allow the springs to be used. Remember, each spring is about 6" in diameter and that has to be factored into the design. Especially when you figure where the spring captures are on the frame.

As for the adjustment on the radius arm. You don't need to be able to move the axle forward or back. The only adjustment you want is for making Caster adjustments, and that can be put on the upper arm where it's stronger.

My goals are to have a comfortable and capable daily driver that can haul at least what the truck is rated for, get my 4wd functional with as little actual downtime as possible and to keep costs low. Im not building an offroader, just need to get my tools and trailer to jobsites through snow mud etc. I don't care much about adding lots of suspension travel or articulation, I have my Ramcharger for wheeling.


You can have comfortable and capable with leaf springs, if you pick the right set of springs. Coils can be a bit smoother if they are the right spring rate but it's going to take more time and cost more to fabricate a coil spring suspension because of the links needed, that are part of the design. A simpler and effective idea is to find a set of leaf springs that are longer and softer and remove that big X-member. Then all you'll need to fab up are the spring shackles and hangers, and simply bolt on the axle to the springs using the existing hardware.

Ed
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Re: Coil springs & radius arms for d350 to w350 conversion

Postby Horus » Sun May 13, 2018 8:52 pm

Liftarc,

Are you still looking at this thread? If so how is this coming along? I'm no fab pro but my wheeling rig is a 1996 Grand Cherokee with roughly 3.5 inches of lift an 42 inch TSLs. I run a kingpin style dana 60 in the front of my rig. The biggest question facing you with this project is Packaging. Being as it's been six months since you posted, I bet you've learned that. :D

Anyway, if you're still in the planning stage I'd love to kick in any knowledge I can provide from experience with axle swaps.
91.5 W250 Dodge 4X4 CTD. Getrag. DD Power pin removed, stock fuel cone back in. 366 spring. Power screw at stock depth. Stock turbo. Stock lift pump. Straight piped and Intercooled.

93 D250 Dodge club cab 2wd. All stock for now. Automatic.
Hard KOR Wheeler.
PNWJeep club member.
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Re: Coil springs & radius arms for d350 to w350 conversion

Postby liftarc » Fri Jun 29, 2018 8:45 pm

I'm still kicking this one around. I've
been driving the piss out of the truck till a couple weeks ago when I blew up the rear end, hence my new thread.... I'm working 60hrs a week building the new Russian River brewery, wife and I had another baby, bought a house, blah blah blah. So I haven't had time for much wrenching but its still in the works. On a positive note, the fuel system I put together has been great and my downpipe/dump exhaust is still loud as fawk.... :mrgreen:
92 D350 club cab flatbed dually-201k G360, NP205,D60 swap soon
92 Ramcharger 5.9 Magnum, 46rh, NP241-238k
liftarc
fuel screw!!!!
 
Posts: 94
Joined: Thu Mar 03, 2016 1:28 pm
Location: State of Jefferson
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