Front LCA pivot point

[Jumbo240z]

Has anyone relocated the front LCA inner pivot point UP 3/4". I've heard it's done to help cure bump steer on lowered street driven 240z's.

Just curious.

Thanks. Jon

[kthomas]

Not in IT (that'd be illegal), but for a street car I know some folks who've done it. In IT some people run the so called bump steer spacers, although unless they're a permanent part of the strut (which can be replaced) they'd also be illegal. I have run nearly back-to-back tests with and without a bump steer spacer on a Z and the stopwatch and driver couldn't tell the difference. For a street car with more suspension deflection and roll maybe you could tell a difference, and on paper it helps.

Our biggest problem on an IT Z is getting enough camber in the front. We noticed that not all front crossmembers are created equal, and if you hunt around enough you can find a factory stock crossmember with the lower control arm holes farther apart (up to 1/4 of an inch!) than others. Might be an actual model year specific change but we didn't go to the trouble of correlating that.



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katman

[x-ring]

Katman, did you ever have any sucess with those offset bushings? I fooled around with them for close to a year trying to find some way to make them hold a position. Short of fabricating one out of steel and welding it to the crossmember I'm out of ideas. I don't think that it would be legal anyway.

That's facinating information about the LCA holes, I'll have to check my stash.

Sorry about the hijack, Jon. It just seemed like an appropriate time to ask the question.



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Ty Till
#16 ITS
Rocky Mountain Division

[Jumbo240z]

Thanks for the info katman. Yea it sounds illegal for IT since you're changing the suspension location points.

I haven't noticed any bumpsteer on the track either, but there are other guys that swear it's an issue. Maybe they're running softer rates than I? Anyway, don't shoot me! but my car isn't an IT car. Though I figured if anyone knew about suspension it would be here and I truely appreciate it.

X-ring, no problem at all.

Thanks. jon

[kthomas]

We have used the old Kontrolle style offset camber bushings in a pinch, but I don't like them because they bind up the suspension until they get sloppy, and then you have a sloppy bushing. What I mean is the inner front control arm pivot has to rotate about a longitudinal axis (think rotate about the bolt axis) as well as a laterial axis (think rotate about a line drawn thru the left and right bushing). This is because the T/C rod is attached to the control arm and pivots about where it does. Therefore, until the bushing gets sloppy the suspension binds and the control arm and T/C rod bend. Lots of people get away with that but I don't use them. We try to get camber other ways.

For a non IT car I'd use the bump steer spacers and/or relocate the LCA pivot to maintain a slightly downward orientation of the LCA for negative camber gain in roll and better bump steer.

[x-ring]

OK, I had kind of suspected the same. I'm not sure what 'other ways' you might be refering to, other than adjustable plates at the top strut mount. I have a set of those installed, from Ground Control, but they will only give me 1.5/1.6 degrees negative camber (L/R) and it looks like that is all there is to be had from the top.

As I mentioned earlier, I'll dig through my parts cars and see what's up with the crossmember hole locations. Maybe one will be better than what I have.

Any other suggestions?



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Ty Till
#16 ITS
Rocky Mountain Division

[Parrish57]

I'm looking for alternatives to the offset bushings myself. This past weekend at Carolina Motorsport Park my bushings spun in the LCA. They had never done that in my old Z. The result was toe out of almost 2 inches. I absolutly SMOKED a set of good front tires. Is it legal to drill a hole to put in a set screw?

[Tom Donnelly]

Keith,

What kind of bushings were you using?
I'm using the camber plates and offset bushings. Did you ever try rod-ends?

Tom

[ITZ34]

I've had them spin also with the results being about 90 degrees of play in the steering wheel. A bit hairy at speed. I use a big breaker bar to keep them tight, and check them before EVERY session. I can only get 1.8- 2.0 with them and Ground Control plates. Not sure how others get 3.0 to 3.5. Ground Control suggested having the struts bent at the bottom, but I'm not comfortable with that. Fortunately, my tire temp readings are acceptable (10 - 12 degrees difference) so I'll live with it until I figure out somethiong better. I would really like to have more adjustment just to play around with. I have the opposite situation in the back.

DC

[kthomas]

Tom:

Sorry for the delay, been out. We've used the Tilton spherical bearing for the front control arm pivot. I think you'd have to get it from Don Oldenburg at DP Racing now. Then you have to get more camber somehow.

DC: I have had Z struts bent like Ground Control suggests. There's a shop in town that has a device for that exact purpose. It ain't an exact science and it's scary and ugly to watch. We don't do it that way anymore. I usually cut the tube about 3/4 through from the inboard side at the bottom where it enters the spindle forging. Then bend the strut tube and reweld a filler back in the gap with two layers of weld to capture the forging too. This method usually won't interfere with the shock insert, depending on brand. The limit to how much camber you can add this way is dependent upon tire to strut/spring clearance and you usually end up with 1/2 inch wheel spacers. Be sure to leave at least 3/8 clearance because the tire will pull over at the top under cornering. I prefer 1/2 inch.

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katman

[Tom Donnelly]

Keith,
Thanks. Going to take a close look at my current setup this weekend.

Tom

[ITZ34]

Thanks Keith:

I guess there's no easy way. I think I'll look for another set to play around with, so I don't screw up the ones I've got.

DC

[ITZ34]

Katman:

You wouldn't happen to have the part # for the gland nuts for 280Z struts, would you?
I ordered the part # you listed from a previous post with the struts, but I didn't think about the fact that the 280 struts are 55mm, not 50mm. Having trouble finding this out from Bilstein, because they don't have Datsun applications. If not, I'll probably have to machine out the centers of the ones I use with the Tokicos, which I'd rather not do.

Thanks

DC

[Parrish57]

DC... I don't know the part number for the 280Z but I think I know of someone who can help you. His name is Jack French. He works for Bilstein. He knew the part that I needed for my 240Z immediately. His number is 800-537-1085. I hope this helps.

Steve ITS 240Z 57

[Tom Donnelly]

DC,

Another place to try is Courtesy Nissan.
1-800-527-1909 www.courtesyparts.com
They have Nissan Comp parts on the web.
And the 240/260/280z microfiche is on the web. http://www.carfiche.com/s30/

Tom

[kthomas]

Yup, give Jack French a call at Bilstein. The 280 struts are different.

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katman

[ITZ34]

Thanks for the help, guys. Bilstein has the parts on the way.

DC