Thread: Rearend links- 4 link, 3 link, parellel, angled???

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That should be a nice compact rear suspension. Should look Cool.

Thanks Pro.
Question for you.

You said "I would make is to be sure the adjustment holes in the 4 link brackets are in an arch that follows the same arch the link would make if you removed the bolt though the hiem & moved it up and down from the top to bottom adjustment holes. That way when you make adjustments from one hole to the other the holes will line up without changing the link length. ''Hope that all made sense''.

I was trying to figure out exactly what arch was used on a number of other brackets I looked at. They didnt match the swing of the link.

For instance- pick a link, any link. Lets say the top link. The rear bolt is installed, say in the middle hole. Remove the forward bolt and swing the link up, hole matches, swing the link down and the hole matches. Now move the rear bolt to the bottom hole and none of the holes will line up in the forward bracket. If that makes any sense.

Does that make any sense?

Sorta' like these brackets.
Whether they line up in the real world. But the adjustment holes have a slight curve in the row.

Well it looks like that pic. post upside down.

While messing around trying to find a comfy spot for the coil over shock, I came up with this. Plenty of room there.
The bell crank drawn is a simple one for concept purposes but it seems to work great. These 2 pics show it in 2 positions. A simple link coming up off the rear end tube should work.
I can increase or decrese the ratio of shock/spring action by adjusting the holes in the bell crank. Kind of like laying the shock over at an angle.

What do you thing about this setup?

I have been messing with this all day. I think I have it.
Some fine tuning is still required, but all in all, I think it will work.
I still need to add the watts link and develop a pivot for the shock bell crank.
A couple cross members and some gussets get added next.

It seems like there is a lot going on, but I dont see how to simplify it much.
Good thing I have a pattern following flame cutter (poormans laser) and a good drill press.

Any ideas what would make a good bearing or bushing in the shock bell crank? The weight of the rear of the car is pivoting on this point and I am not sure how to bush that pivot.

And why are my pics so big? I am not doing that on purpose.

How about Johnny Joints. They were mentioned by 27tee and linked by ceh383 and would seem to be a viable mechanism to use in this application. Here are different sizes....
2" with grease zerk...
http://www.currieenterprises.com/ces...t.aspx?id=1167
2 1/2" with grease zerk...
http://www.currieenterprises.com/ces...t.aspx?id=1166
3" with grease zerk...
http://www.currieenterprises.com/ces...t.aspx?id=1081

It may be the angle or the way I'm looking at it, but visualize a line through the shock centerline and another line extending through the shock eye and the pivot point of the rocker arm. These would appear to be somewhere close to a 90* angle and that's how I would do it too, although I'd figure the angle so that the rocker was halfway through its arc at half suspension movement, the same way you set up valve spring rocker arms in a motor.

Now, visualize a line from the c/l of the diff up through the mount on the rocker arm and another line extending through the upper rocker arm mount and the rocker pivot point. The angle would appear to be somewhere around 110* and will increase as the diff goes into bump. With this arrangement, as the diff goes further and further into bump, it appears to me that the spring movement gets less and less, so you have a decreasing amount of spring as the bump gets longer.

I'm no guru on this stuff, I just parrot what I have learned from others. But in this case, I think I would rather have the progression of the spring rate at least linear, if not increasing a little as the suspension increases in bump.

Then again, I may be looking at it all wrong because I have not seen a side view of the geometry.

Originally Posted by techinspector1

How about Johnny Joints. They were mentioned by 27tee and linked by ceh383 and would seem to be a viable mechanism to use in this application. Here are different sizes....
2" with grease zerk...
http://www.currieenterprises.com/ces...t.aspx?id=1167
2 1/2" with grease zerk...
http://www.currieenterprises.com/ces...t.aspx?id=1166
3" with grease zerk...
http://www.currieenterprises.com/ces...t.aspx?id=1081

Are you suggesting using them for the bell crank on the shock linkages?

I would think that something like the roller camshaft bearings could be used in and fabbed pivot----they are available in various sizes

They will be carrying the weight of the vehicle so will need to be pretty robust

Originally Posted by jerry clayton

I would think that something like the roller camshaft bearings could be used in and fabbed pivot----they are available in various sizes

They will be carrying the weight of the vehicle so will need to be pretty robust

I looked at some roller bearings (not for a cam though) and they need a hardened surface to roll on. Do cam bearings have an inner race?

There is a watts linkage on the market that uses tapered roller bearings, like wheel bearings. A little big but might be a solution, what do you think?

Here is a side view at ride height.

The shock is compressed 1/3 of its travel.
4 inches of bump from this picture and the rear end hits the frame ( I am planning on 3" of travel and a rubber bumper)
1.5" of droop from this picture and the shocks are fully extended.

Techinspector, I did struggle with the geometry of the shock/bell crank thing and fully admit I am just guessing. Love to hear more.

Should I keep the bellcrank working at a 1 to 1 ratio or increase one side or the other?

Any unusual forces on the bellcrank pivot or just the weight of one corner of the vehicle?

Thanks all for contributing.

Originally Posted by maddddog

Are you suggesting using them for the bell crank on the shock linkages?

Yes, the rocker arm pivot. You call it a bellcrank, I prefer to see it as a rocker arm.

Your pictures are so large because you're uploading them at 940 x 637 pixels. You need to resize them before you post them. Cut them down to 640 x whatever before posting.

How about using the same bushing GM used on the trailing links on the 60s - 70s GTOs, Chevelles, etc.?

I would use a 1:1 ratio. Then you're not fiddling with your shock rates.

Also, you'll have to mount your shocks upside-down, won't you?

Originally Posted by Henry Rifle

Your pictures are so large because you're uploading them at 940 x 637 pixels. You need to resize them before you post them. Cut them down to 640 x whatever before posting.

How about using the same bushing GM used on the trailing links on the 60s - 70s GTOs, Chevelles, etc.?

I would use a 1:1 ratio. Then you're not fiddling with your shock rates.

Also, you'll have to mount your shocks upside-down, won't you?

I will look into the GM bushings, thanks.

Upside down? I hadnt thought about that. Why upside down, or are you messing with me?