front sway bar hitting frame rail

[mrk3cobra]

I just installed an upgraded St performance front sway bar on my LS2 240Z. The bar is a 1" diameter, you can see in the picture the bar is resting against the frame rail with the car sitting on the ground. Do I have to install a spacer at the frame rail to use a 1" sway bar?

[ZHoob2004]

If it's hitting, then you probably need a spacer. Adding a small spacer won't really affect the performance of the bar, and can be as simple as a small piece of steel with a pair of holes drilled in it.

[mrk3cobra]

I would think if all larger sway bars need a spacer to work, they would include in the kit. Most people would not notice and just install the kit and the bar would be hitting  the frame and as the wheel goes through compression the frame would stop the bar from rotating.

[jhm]

I think one of the reasons it's hitting is either your end links are too long, or the car is significantly lowered, or both.  There's not a lot of "plug-and-play" or "one size fits all" parts made for these old cars.

 

You can easily shorten your end links, if that's part of the problem  Length can easily be adjusted (shorter or longer) by changing overall length of bolt and the spacer.  

 

I would use the spacer, too, as zhoob suggested.

Edited February 14, 2020 by jhm

[ZHoob2004]

Also maybe a dumb question, but is the bar centered on the mounts? I would think the bends would be far enough apart to clear the rails...

[mrk3cobra]

yes, both sides are hitting the frame rail.

[JoeK]

Mine looks exactly the same. I guess I’m one of those that didn’t notice. My car isn’t particularly low and the end links aren’t getting any shorter either. Guess I’ll add some spacers, anyone think 1/4” thick will be enough?

[mrk3cobra]

0This is a 1/4" spacer. I also do not like the angle of the tie rods.

[mrk3cobra]

I will cut the spacers at the sway bar links, when i get new outer tie rods.

 

[jhm]

Mrk3cobra, your LCAs appear to be past horizontal, which means your negative camber may actually be decreasing as the suspension compresses (not an ideal situation).

 

I would definitely recommend some bump steer spacers, which should improve your suspension geometry, improve your tie rod end geometry, and help solve your sway bar intereference issue.

Edited February 18, 2020 by jhm

[mrk3cobra]

JHM, who sells bump steer spacers for OEM outer tie rods?

[jhm]

Available from many sources....T3, Silvermine, DP Racing to name just a couple.  I've even seen them on eBay from generic vendors.  They go by other names as well:  "knuckle risers", "roll center adjusters", etc.  One caution when using these is that they can cause interference between the steering knuckle and the rim on 15" wheels or smaller.  

 

You can also relocate the LCA mounting hole on the crossmember to improve LCA geometry.  Common mod that's been discussed quite thoroughly here on HybridZ.

 

Finally, it appears as though your 1/4" spacer is giving you sufficient clearance for your sway bar vs the frame rail.  So that's some progress, at least? 

[JMortensen]

10 hours ago, jhm said:

Mrk3cobra, your LCAs appear to be past horizontal, which means your negative camber may actually be decreasing as the suspension compresses (not an ideal situation).

 

I would definitely recommend some bump steer spacers, which should improve your suspension geometry, improve your tie rod end geometry, and help solve your sway bar intereference issue.

This is incorrect. I was under the same assumption and blueovalz fixed me up about 15 years ago. The way it works is that the negative camber increases (very linearly) until the spindle is perpendicular to the control arm, then you would see camber go more positive. I think this is practically impossible to do in a Z, so for all intents and purposes it's not going to be an issue.

The real issues are having the roll center underground, and bumpsteer. Roll center might not be underground at this particular car's ride height, but if it does end up underground it will require more spring to get the same amount of body roll. Basically gives you some "pro roll" in the suspension geometry. The bumpsteer is bad on a Z, but if you get low enough it gets really wacky. I had a situation where I was running really low without fixing bumpsteer and there was a sharp rise in the track, and when I'd hit it my car would jerk hard to the right, like an emergency avoidance maneuver that it just decided to do on its own. Fixed bumpsteer by raising the inner LCA pivot about 7/16 and that was gone.