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Weird S/T rear sway bar problem....


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Well, a good racer friend of mine is helping me out with the suspension on my 280z. He's had like 12 of them, each of them quite modified. He has run into a weird problem though.

 

The stance of the car looks insanely sweet, but he's afraid of too much strain on the rear end links.

 

The bottom of the link is horizontal, but the sway bar end is not.

 

To get that end to be parallel to the bottom, the car would have to be lowered like another four inches, which would probably leave the car resting on the exhaust (in fact he claims the stock exhaust isn't going to last because of how low the car is, it needs to be tucked up).

 

He had the same setup before but it was before S/T switched to these lime colored "improved" bars. First we thought maybe the car was too low, but in fact if it was higher the problem would be worse.

 

The bar came with instructions labeled for a 76-78 280z, so it appears to be the right one. Every fit fine, it's just the rear end links....

 

Any ideas?

 

 

I might be able to get some pics but that won't be till a few days....

Mario

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I don't know how a ZX sway bar mounts up, but I assume it mounts to the front. You should be able to change the length of the end links to get something appropriate. I remember my Toyota truck came with 2 sets of end links. Longer ones for stock height, and shorter ones for lowered trucks. You'll just need longer or shorter bolts and spacers to fit between the bushings, everything else should be the same. If you can I'd check to make sure that the suspension can move all the way through its travel without hitting anything, that's the most important thing.

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This is for a rear 78 280z suspension techniques sway bar.

He feels that the angle will cause damage to either the sway bar or the end link bolt.

 

This is how it looks...

 

 

...=||= ...... <- top of end link and bushing

___/||/ ...... <- sway bar end (it's at an angle)

____||/ ......

...=||= ...... <- bushing

....|| ....... -> rear of car

....|| .......

...=||= ...... <- bushing

::::||::: .... <- bottom mounting point (horizontal)

...=||= ...... <- bottom of end ling

 

In other words, the end link is vertical but the bushings and washers sit a little angled on the sway bar end because of the end link mounting surfaces are angled. This is with the car settled on all 4 wheels.

 

If that picture doesn't help... I'll try paint next.... the car is an hour away and he doesn't have internet, so pics are a little hard to get, sorry.

 

Mario

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I think I follow. The ends aren't going to be parallel. Most of the way through the travel the bar and the trailing arm are going to be at an angle to each other, because the trailing arm and the sway bar end aren't going to move in the same arc. I don't think you really need to worry about the situation you're describing there.

 

Even if you make them parallel at ride height they'll be all over the place as the suspension goes through its travel. See: http://forums.hybridz.org/showthread.php?t=105596&page=5

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I understand the suspension will be moving, but in your case you put in custom end links with heim joints (something we were actually discussing).

 

We are just using the bolt and urethane bushings that came in my kit Energy Suspension kit.

 

My friend is just worried that the sway bar will grind through the bolt or the bolt will grind through the sway bar, leading to failure of one part or another. I'm going to call S/T, but you're right, it might not be an issue.

 

I'll post what S/T says.... if I can find a number....

 

Thanks for your replies,

Mario

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Wow, suspension techniques are jerks!

 

My friend called them in the morning and he mentioned the fact that the wrong product might of been shipped, and they're like "go talk to summit first, then us".

 

I called them in the afternoon, like 15min before closing, and the guy was at first saying "send me pictures", I mentioned the car was an hour away, and now he wanted measurements....

 

So it looks like we're pulling it out, measuring it, and probably sending it back....

 

Dammit.... if it wasn't for this, the entire suspension would be done this Thursday....

 

Car looks amazing with how low it is, and it should handle great!

Mario

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I actually had the same problem with the rear of my 280ZXT with the MSA swaybars. It turns out when they manufactured them they didn't get the angle of the "tab" were the end link goes through correct. A heated phone call to MSA corrected the problem, as they sent me a new bar.

 

Aaron

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After speaking to them on the phone again (S/T), we are going to send pics to them tomorrow.

 

They also offered to overnight a bar if it is indeed bad.

 

Doesn't matter at this point, we have to do some mods to the front crossmember to get 2.5* of camber in the front anyways....

 

How I long to drive the damn thing....

Mario

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Well... S/T is really dragging their feet on this problem.

 

I should have an answer on Monday supposedly....

 

Here are pics of what I was talking about:

http://album.hybridz.org/showgallery.php?ppuser=12144&cat=500

 

But wow, drove the car today without the rear bar and it is so awesome. Still need the car aligned, gonna run a nice amount of neg camber, a proven amount of toe in the front, and I'm gonna slot the rear shock towers for camber in the rear.

 

Right now ALL bushings have been replaced with the urethane ones, once the sway bar issue is resolved in the back, the car has gotten new sway bars, and the car looks menacing being so low.

 

I'm gonna have to get a new exhaust (something more tucked up) and learn how to drive all over again with 3" of ground clearance to the frame rails....

 

Can't wait!

Mario

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That really doesn't look that bad to me. You have to be pretty far out of line with a semi-trailing arm suspension because when the arm moves the pivot point will swing back and out. If it moved straight up and down then you could point the end link right at the hole in the arm, but it doesn't. You could pull one of the struts off and attach the bar on that side and swing the semi-trailing arm up and down through it's range of motion and see if it gets better or worse as the suspension moves. I'd bet it looks a lot better when the suspension is at ride height. I know mine did.

 

If I were you I'd slot the rear crossmember for camber and toe. IIRC, and I might not, the ZXT has bushings at both ends of the strut. So if you slot the strut tower and move the top of the strut over you won't actually change the camber, you'll just compress the bushings on the ends of the strut. As camber changes on a semi-trailing arm toe also changes, for this reason you need to be able to adjust both.

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This is all for a 78 280z, so slotting the towers will allow for camber adjustment.

 

Also, all the pics were take with the car set on wooden blocks to put load on the suspension. The only time the angle would get better would be when the suspension is bottoming out. Any other time and the angle would be worse.

 

How do you get toe adjustment for the rear of a 280z?

 

Mario

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Oh, I thought this was for your ZXT. If that was in the middle of the travel I think you might have a beef with ST. Sorry I wasn't following that part at first. It looks to me like if you could straighten that last bend a little bit you'd fix the issue. I was able to bend my 3/4" bar in a 12 ton press pretty easily. I think yours is 7/8", might be doable.

 

Rear toe adjustment on a 280, well, you can get G machine camber bushings, or you can make your own variation of the poor man's toe adjuster: http://forums.hybridz.org/showthread.php?t=89111, or you can get adjustable control arms from MM or AZC.

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Yea, we were thinking about getting camber bushings and just putting them on the front of the suspension arm, and put rubber bushings, maybe urethane would also work, in the rear and adjust toe that way.

 

Car seems to be pretty toe'd in in the rear, and in the front my tie rods might not be long enough to run 2.5* of camber up front and the right toe since we repositioned them on the cross member.

 

Need to double check it though, but it should be fully dialed in next week, with or without the rear bar. If S/T keeps this $h!t up I'm gonna return it to Summit.

 

Thanks for the responses,

Mario

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Yea, we were thinking about getting camber bushings and just putting them on the front of the suspension arm, and put rubber bushings, maybe urethane would also work, in the rear and adjust toe that way.

Why not just use them at both ends? They're a lot more stiction free than poly, and I think if you buy them you get all of the adjusters for the rear control arm as a set.

 

Car seems to be pretty toe'd in in the rear, and in the front my tie rods might not be long enough to run 2.5* of camber up front and the right toe since we repositioned them on the cross member.

The stock specs allow for a pretty healthy amount of toe-in out back, but what you want to look out for is the strut being drilled at the wrong angle. That has come up enough times that it is, IMO, pretty likely that you could have that issue. Need a 4 wheel alignment to check.

 

On the front tie rods, I had that same fear. I just checked the ones on the rack that I'm working on, and the inner tie rods have a full 2" of threads on them. If you follow my 1.5x the diameter in the threaded section rule of thumb, then you should have about 13/16" inside the tie rod. That allows for a decent amount of lengthening the control arm.

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The stock specs allow for a pretty healthy amount of toe-in out back' date=' but what you want to look out for is the strut being drilled at the wrong angle.

[/quote']

I don't quite get what you mean by this. The struts are Tokico Illuminas and they all looked identical. Could you explain this more?

 

I just checked the ones on the rack that I'm working on' date=' and the inner tie rods have a full 2" of threads on them.

[/quote']

That's good to know, I'll recheck how far out they are now.

 

Thanks again,

Mario

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There have been quite a few threads that have come up in the past few years where there was a very large amount of toe in in the rear. Turns out that some of the struts were just plain manufactured wrong, with the hole for the spindle pin drilled at an angle which causes pretty severe toe in on one side or the other. John Coffey was the first one that I saw actually identify that this was due to the strut being manufactured incorrectly.

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  • 1 month later...

Ok, it seems like the bar was defective, and they sent a new bar! Got here today!!!

 

(The guy said "I can't believe that thing made it through quality control... it was really off.")

 

So, I have this and hopefully (fingers crossed) twice pipes and 3 into 2 headers comming. I think I'm staying NA. The car supercedes my skill to drive it at it's current state anyways.

 

Mario

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Hey Mario,

I was just checking out your sway bar problem, and I noticed your wheels. Are you going to run those wire wheels? In the photo it looked like they hung out quite a bit from your fender. Im building a wide body and I could use them if by some chance you're not going to use them.

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