Gonna build my own 4-link....any thoughts/suggestions, and I have a couple questions

[davidk68]

Hello guys,
I'm planning on building my own 4-link for my 68 Camaro. I'm planning on a triangulated 4-link similar to the Alston g-bar/link. I will use the front leaf spring mount for the front lower bar mount. I'm planning on using axle brackets from Ridetech for the axle lower bar mounts. I'll make the upper axle mounts out of square tubing with one side cut out. I'm going to gusset the inner frame rails with 1/8" plate in the area of the front upper mount. The mount itself will be 3/16" plate. I am using 1.25" diameter, 0.120 wall tubing for the bars. I'll use johnny joints or a combination of jj's and urethane mounts. I'm planning on running the shocks up into the trunk like DSE so they don't hang down so low like on the Alston systems. Car stats are 383 ci, 450 hp/450 tq, Viper T56, 12 posi 3.73/3.90 gears, 17" wheels (17x11 rear, mini-tubbed), mostly street driving with occasional autocross and track-day. I have a few questions:

1. Should I run johnny joints at all ends similar to the g-link? I was thinking of running polyurethane on one end of the bar. If I do this, should the poly be on the axle or the frame. It may help to have the jj on the front lower to clear the tire??

2. Is there a minimum bolt size I should use? One of the johnny joints I saw on Currie's website uses a 7/16th bolt. I think the stock leaf spring bolts are 1/2".

3. Anybody recommend a good spreadsheet for calculating the geometry?

Thanks in advance for your help,
David

[MrQuick]

I was using JJ's for a while then switched to Spohn ends just due to the ability to use a larger through bolt.
http://www.spohn.net/shop/Del-Sphere-Pivot-Joints/

The Spohn has a smaller body overall but the through bolt is 3/4" and used with high misalignment spacers you can drop down to 1/2" if desired.

http://www.barnes4wd.com/index.php?cPath=244 i like to use these guys, they also do custom brackets to your specifications.

Do a search for members Billy Shope and Norm Peterson here. They have a few excellent resources for rear suspensions. Think CornerCarvers without the attitude.
Vince

[davidk68]

Thanks for the info MrQuick. The Spohn joints look like nice pieces and the video is very informative. Very similar to the johnny joint only with delrin instead of polyurethane. So which is better? Delrin or polyurethane? Still not sure if I should run a swivel-type joint on both ends??

[MrQuick]

Hey David, at the most run the ball type at the axle side.

Delrin will have less deflection, will last longer but will transfer NVH a bit more than poly.

Poly runs hotter so it might use more grease than the delrin used in the same application. Higher friction could be due to lubrication used. But I have found that poly required more frequent re-greasing much more than the Del's. Maybe the del ball dissipates heat faster? Un known. Arguable, I know but its just what I have noticed.

You can also adjust the pressure on the delrin and ball with an adjustable plate/lock screws. (Spohn)

I went with the Spohn just for the compact housing and larger through bolt.

vince

[chevyhector]

I'm gonna keep an eye on this thread, sounds like something i might do in the near future. Remember the pic's ! They will be a huge help.
:jump:

[davidk68]

Quick - do you mean at the least, run the ball type on the axle side and regular poly bushing at the frame, and then a better system or upgrade would be ball type on both ends?? I'm a little confused by your reply.

I have Global West front upper and lower control arms with Delrin bushings and I didn't feel any increase in ride/harshness. But it is mostly a street car so I do like the polyurethane. Maybe I'll flip a coin :cheers:

Chevy - I'm putting in minitubs first so it'll be a few weeks at least until I start with the 4-link. But, I'll try to keep the post updated.

[chevyhector]

Thanks ! I'm currently starting a 12 bolt conversion and I wanna install a 4link. I'm also planning to do a mini tub on my Camaro.
So, i have a few weeks to wait.


Chevy - I'm putting in minitubs first so it'll be a few weeks at least until I start with the 4-link. But, I'll try to keep the post updated.[/QUOTE]

[JRouche]

Hey Vince, good points.. I think the friction with the poly is what causes it to get warmer and needs more grease. A high quality grease might help in that area too. I use lubriplate "special auto-marine grease" for all of my suspension points that need grease. Its a very high performance grease thats compatible with most suspension parts. http://www.lubriplate.com/webstore/detail.aspx?ID=7

I for one would opt for the delrin bushed joints. A lil NVH is not as bad as a failed poly joint. I wish the manufactures would use Delrin AF in their rod ends. It has some great specs, perfect for suspension joints. As long as they are not too close to exhaust heats. AF cant withstand the heat as well as Delrin without the teflon. JR




Hey David, at the most run the ball type at the axle side.

Delrin will have less deflection, will last longer but will transfer NVH a bit more than poly.

Poly runs hotter so it might use more grease than the delrin used in the same application. Higher friction could be due to lubrication used. But I have found that poly required more frequent re-greasing much more than the Del's. Maybe the del ball dissipates heat faster? Un known. Arguable, I know but its just what I have noticed.

You can also adjust the pressure on the delrin and ball with an adjustable plate/lock screws. (Spohn)

I went with the Spohn just for the compact housing and larger through bolt.

vince

[MrQuick]

Quick - do you mean at the least, run the ball type on the axle side and regular poly bushing at the frame, and then a better system or upgrade would be ball type on both ends?? I'm a little confused by your reply. Yes, ball on both ends can be considered over kill unless you really need the extra articulation. I'd run at both ends if you can afford it.

I have Global West front upper and lower control arms with Delrin bushings and I didn't feel any increase in ride/harshness. But it is mostly a street car so I do like the polyurethane. Maybe I'll flip a coin :cheers: Then you are part of the 75%ers. :1st:

Chevy - I'm putting in minitubs first so it'll be a few weeks at least until I start with the 4-link. But, I'll try to keep the post updated.
Cool, fit your rims and tires then make the suspension fit. my reply in bold

picture of the difference between the spohn(3/4") and JJ(9/16)

[BillyShope]

3. Anybody recommend a good spreadsheet for calculating the geometry?
Page 13 or Page 40:
http://www.racetec.cc/shope

[davidk68]

Thanks for the info guys, I've been traveling for work alot lately and haven't had time to post or work on my car, plan to this weekend though.

MrQuick: I am probably going with the Spohn's also as I like the bigger bolt and the ridetech brackets use a 5/8 bolt. I noticed on your bars the ends thread straight into the bar insted of a welded bung. What is the I.D. of your bar with the Spohn ends?? I can probably afford to go with all Spohn ends but was thinking of poly ends on the frame side with Spohn's on the axle. I plan to offset the front lower mount so a ball end may be better here. I know 1st gen camaro leaf springs are angled but not sure about the front spring pocket. I have my rear wheels and tires and have done a rough mock-up and it looks like it's gonna be close. Need to do my min-tub to be sure.

Billy: thanks for the link, I plan to check it out this weekend

david

[chevyhector]

Looking good, thanks for the info.

Billy, i really apreciate the "racetec" spreadsheet ! Thanks.

[MrQuick]

Hi David,
*just to note the upper arm in the picture is the Spohn equip arm (upper link).
I just use your average Late model sportsman recipe.

Links are built with:
1.0 OD .156 wall DOM 5" long tapped for 3/4" threads and then pressed and tigged into 1.250 OD .095 wall DOM. The length depends on the build. I can make 2 sets of lower arms for about $150 minus the joints. Taps (3/4" RH & 3/4" LH) are about $14 each.

Billy's spreadsheet will help you a lot with that. I usually run the longest lower arms possible then adjust the upper and make it fit running placement numbers calculated with Billy's site.


On first gens you can straighten the arms out by using the stock spring perch. I'd recommend leaving enough room on both ends to keep the ability to adjust your LCA inwards or outwards for tire clearance.(1) Space the joint with high misalignment spacers (3/4" to 5/8" bolt) then just adjust the mounting bracket location on the axle. I don't believe there is a need for the convergence on links if you plan on a panhard or Watts.

1. Side note, I have 1/2" clearance between my tire and the lower links with 335's on 12's. I still have room to adjust with spacers alone.


Good luck with your build.
Vince

[jtm311]

David, Not sure if this will help, however, the pricing seems good I have not purchased from them but I will once I start mine.

http://www.welderseries.com/catalog/index.php?cPath=22

John

[Norm Peterson]

(later)

[MrQuick]

...great, Norms gonna leave us hangin. LOL

Love that welders series site, super clean metal.


Vince

[ErikLS2]

I started this thread on this last year with the same plans, then was going to just stick with leafs and now I'm back to doing a 4 bar again. Some relevant information in it I think.

https://www.pro-touring.com/forum/showthread.php?t=57774

The G-Link installation instructions are a great reference too.

http://www.cachassisworks.com/Attachments/Instructions/915804-F10.pdf

[elitecustombody]

Hey David, at the most run the ball type at the axle side.

Delrin will have less deflection, will last longer but will transfer NVH a bit more than poly.

Poly runs hotter so it might use more grease than the delrin used in the same application. Higher friction could be due to lubrication used. But I have found that poly required more frequent re-greasing much more than the Del's. Maybe the del ball dissipates heat faster? Un known. Arguable, I know but its just what I have noticed.

You can also adjust the pressure on the delrin and ball with an adjustable plate/lock screws. (Spohn)

I went with the Spohn just for the compact housing and larger through bolt.

vince

Vince,thanks alot for the info posted, how is the road noise transfer with spohn joints? Are you running them on both ends or just the axle housing side?

OP,I didn't mean to intrude,I'm in the middle of search for the right components for my suspension and this thread has alot of good info and links,please let me know if I'm stepping on your toes.

Stefan

[MrQuick]

Hi Stefan,
I have yet to drive the car with the Spohn's. Just started to use them this year switching from JJ's.

They shoud be similar to the other Del-alum setup being used. I find them harsh but if you ask another person and they would not even notice the difference.

The JJ's are smooth.

I run them on both ends. In the long run its cheaper for us.



Steel toe boots are always on.

Vince

[davidk68]

Thanks for all the info guys. John, I did check out the welders series brackets and the #318532 is similar to the Ridetech #A113 I am looking at. I'm leaning toward the ridetech because the front is "straight" and I can drill additional holes for adjustment of the lower bar in it.

Erik, awesome link to your thread, lots of good info there. What are you planning for your set-up? The g-link instructions are very much appreciated. I gotta say, from seeing the up-close pictures, the g-link looks like a very nice product. Too bad I can't buy just the pieces I want.

Vince: I know the answer to this depends on car hp, traction, braking ability, g-forces etc., but could the 1" OD 0.156 bar be run full length without the 1.25" OD splice?? Even though I'm just running 315's, I wouldn't mind a little extra tire clearance. I will be ofsetting the front lower mount. Is it better to run the Spohn end in a 1" threaded bar as opposed to a welded bung in a 1.25" OD 0.120 wall bar? Disregarding the bar strength, I would think the full thread engagement of the threaded bar would be stronger - but not necesarily needed?? There are plenty of welded bung bars on the market from very reputable companies.

I started my minitub over the weekend and will probably be purchasing bars and brackets this week. I'm going with at least 6 Spohn's and probably 8.

Elite - no problem with the post. I've always thought it was kinda silly that people got upset about that. We're all just trying to get the information we need from the people who know and have the experience. That's what these forums are all about - IMO. :)

[MrQuick]

Vince: I know the answer to this depends on car hp, traction, braking ability, g-forces etc., but could the 1" OD 0.156 bar be run full length without the 1.25" OD splice?? Even though I'm just running 315's, I wouldn't mind a little extra tire clearance. I will be ofsetting the front lower mount. Is it better to run the Spohn end in a 1" threaded bar as opposed to a welded bung in a 1.25" OD 0.120 wall bar? Disregarding the bar strength, I would think the full thread engagement of the threaded bar would be stronger - but not necesarily needed?? There are plenty of welded bung bars on the market from very reputable companies.


sure you can, just depends on your comfort level of fabrication.

I have used AL bars in the past but would not recommend them on a street car or a car I build for a client.

I have never liked the weld in bungs and I don't work with chrome moly.
just a personal preference thats all.
Vince

[ErikLS2]

Erik, awesome link to your thread, lots of good info there. What are you planning for your set-up? The g-link instructions are very much appreciated. I gotta say, from seeing the up-close pictures, the g-link looks like a very nice product. Too bad I can't buy just the pieces I want.


That's kind of what I thought. I was looking under mine last night. I think if I'm going to do it I may try and improve on the biggest compromise of the g-link, which I believe to be the upper arms. I'd like to figure out if moving the axle end of the upper link rearward a bit and attach it slightly behind the diff cover to something similar to what's used on a torque arm setup would be advantageous.

I'm hoping Norm will chime in here. I'd like to know what he thinks of my theory. A Satchell is another possibility I've considered but I'm sure the upper arms would have to intrude into the back seat and I got to put kids back there.