G Link Suspension question

[tmadden]

Have the Alstons G link under my 69. when shifting I noticed it jerks pretty severely sideways and sometime when reducing speed. What is that? could it be as simple as putting the the anti roll bar in and having suspension set with 4 wheel alignment or is there something else I'm missing?

[Ron Sutton]

Have you scaled the car?

Is there preload in the 4-link rods?

Either of those can cause the car to drive left or right, depending on which rear tire has more loading on it.

It's most noticeable under hard acceleration or decel.

[tmadden]

I just got it running and that was the maiden voyage. I still need to have the suspension setup but was led to believe I wouldnt need the panhard bar but it seems I do. You have accurately described my issue. once the panhard bar is installed I will take it for setup and 4 wheel alignment. Hope that cures it.

[Rod P]

Originally Posted by tmadden

Have the Alstons G link under my 69. when shifting I noticed it jerks pretty severely sideways and sometime when reducing speed. What is that? could it be as simple as putting the the anti roll bar in and having suspension set with 4 wheel alignment or is there something else I'm missing?

G-link is a triangulated 4 link...make sure nothing is different lengths often the upper bars are not welded to the Diff squarely and that cause a side shift

[Rod P]

Originally Posted by tmadden

I just got it running and that was the maiden voyage. I still need to have the suspension setup but was led to believe I wouldnt need the panhard bar but it seems I do. You have accurately described my issue. once the panhard bar is installed I will take it for setup and 4 wheel alignment. Hope that cures it.

a triangulated 4 link doesn't need a panhard bar, that will really jack up the suspension....call Alston

[Ron Sutton]

Originally Posted by Rod P

a triangulated 4 link doesn't need a panhard bar, that will really jack up the suspension....call Alston

Agreed. A panhard bar with a triangulated 4-bar suspension will cause binding.

My recommendation is to put the car on a truly level set of scales ... and see what the corner weights are. if you have a lot of wedge in the car ... meaning the LF & RR weights are significantly different than the RF & LR weights ... that will cause the issue you are describing.

The cause of your car having too much wedge ... if it does ... can be either the 4-bar isn't adjusted properly (and you have preload in it) ... or you simply have the spring adjustments uneven.

Check your rear end to make sure it is centered in the frame & square with the chassis. Then loosen the jam nuts and attempt to rotate them with your hand. If one or two are super hard to turn, you may have preload in one of the bars. By "preload" .... I mean one bar is adjusted too long or short which is a binding of sorts & preloads one side of the suspension ... and that scale will read heavier than it should.

If you turn one bar and all the bars "relax" ... that is the clue you had preload in the 4-bar. Once you get the rear end center, square & zero preload (pinion angle correct too) ... then dial in your spring adjustments to make sure you don't have significant wedge.

If you do this with the driver weight in the car, the left side will of course be heavier, so don't forget that. If you do this without driver weight, the car should be fairly close to equal weights left & right. Again, don't let these left side or right side weights through you off. The key is finding significant wedge ... differences in the LF-RR numbers compared to the RF-LR numbers ... and eliminating it.

P.S. If I have a well designed race/track car that weighs 50/50 left & right ... with the driver ... I set the LF-RR total to match the RF-LR total. On the other hand, if I have a production based car that is left side heavy with the driver ... I set the LF-RR total to match the right side weight total of the car. Do with this with spring adjustment & keep the bind/pre-load out of the 4-bar. This makes it handle the same on left & right hand corners.

Best wishes.

[tmadden]

Ron,
thanks for the detailed info. I think I meant anti roll bar. As it is called on their website. It wasnt doing this prior to to having the trans looked at. Not sure where it came from. Gonna get under the car tomorrow and see if I can spot anything.

[Rod P]

Originally Posted by tmadden

when shifting I noticed it jerks pretty severely sideways and sometime when reducing speed.

Originally Posted by tmadden

could it be as simple as putting the the anti roll bar in

what your describing here is a bind or misalignment, that is not what a sway/anti roll bar cures

[tmadden]

Bind or misalignment of what? I'm gonna throw it on lift tomorrow and look for a problem

[Chassisworks]

Hi Tony,
There are essentially two possible culprits.

1- Something is improperly adjusted.
2- Something is loose.

Have you found anything out since your last post?