Urethane bushings

[drunkenmaster]

I have heard from one source recently that the firmness of these can causes structural failure of other related systems and welds.

Any opinion on this?

[biker]

With the stiffer type of bushing, it may contribute.

Look around the race track and you do see a lot of Zeds with stress cracks around the roof line particularly near the hatch.

biker

[260DET]

On the 260Z anyway, the stock anti-sway bay mounts are inadequate and should be beefed up, even when using stock rubber bushes. Using urethane suspension pivot bushes is questionable given the compliance designed into the stock bushes, at the very least they could inhibit normal suspension travel which possibly could lead to component cracks.

On rear pillar cracks, they are the direct result of body flex, nothing to do with urethane bushes.

[drunkenmaster]

So we are getting negative feedback for urethane bushes?

Anyone for them?

[260DET]

For anti sway bars and tension rods they are excellent, providing as I said the former mounts are beefed up. Try the following test on the stock rear bar mounts.

Jack the rear up so that you can remove one wheel. Then remove the bar end suspension arm connecting link from the same side as the removed wheel. Lower the car so that the other wheel is sitting firmly on the ground. Place a piece of pipe over the end of the exposed bar to gain some leverage and push it up/down, at the same time observing the bar mount on the body. You can actually see the mount moving around under load.

[2ManyZs]

I've seen numerous Z's that were raced and many of them never had any problems with the mounts or any structural problems due to using urethane bushings. I think a lot of it may have to do with the condition of the chassis in question as it sits before the modifications are done.

FWIW, I raced a 75 280Z for 5 years with urethane bushings with no problems... and the car was a street car for many years after the first owner rolled it on its side and a friend of mine replaced the bent suspension pieces and straightened the roof. Nothing was ever done to the sway bar mounts, and it is now on the track again after sitting in my backyard unused and neglected for 8 years...

[SledZ]

Ok I am new to the Z and it's suspension. My car is completely stripped of it's suspension and I have all new urethane bushings waiting to go into it. Should I stop and re-order rubber? Am I in for that much of a rough ride compared to rubber?

I have read about all the posts in about all the forums on the web and the majority of the Z's all put in Urethane and I assumed it was the way to go...:paranoid:

Also my Z is in great shape, bit's of surface rust and 51k miles

[2ManyZs]

I'd go for the urethane.... last longer than rubber and you'll get better handling without sacrificing too much ride comfort. The biggest thing that will affect the ride will be your spring/shock choice anyways....If you were planning on adjustable coil overs with 200+ pound springs etc. then I'd say you were heading for ride problems...Stock or close to stock springs with the urethane bushings should be fine for the street. Also, you have to remember that tire size and profile contribute greatly to your handling and ride comfort as well, the lower profile you go, the harder it will ride yet will more than likely handle better.. It's all in how you choose the rest of the components that will give you your best results.

Just remember to lube the bushings with a good grease to prevent squeaks and you shouldn't have any problems.

[SledZ]

Thats reassuring. I am keeping it stock. I bought the KYB struts because they were close to stock and am only going to ride it on the street. Not sure about the wheels yet. I have both stock rims and another set that came off a 280 "I think". I'd really prefer the slotted dish cause thats how I remember them!

Thanks!

[260DET]

Re stock rear sway bar mounts, sure they won't usually break using urethane bushes. But since strengthening them on my 260, rear end breakaway on the track has become much more predictable and progressive, plus, a lighter rear bar can be used.

But if people are happy with the stock setup then thats OK by me.

[drunkenmaster]

I went to a reputable suspension place and spoke to a guy who uses a 240Z in targa tasmania and he was of the opinion rubber all round for the rear with some urethane up front.

Decisions decisions...

[260DET]

It would be interesting to know the reasoning behind the rear rubber sway bar mounts idea. From everything that I have read and from a little practical experience, all sway bars should be as rigidly mounted as possible from a performance perspective.