Very wobbly at high speeds

[misturmoneybags]

I just bought a '73 240Z with tokico shocks and eibach springs but whenever I get onto the freeway and exceed about 60 mph, the ride gets reaaaally wobbly and twitchy.

Is there anything besides worn out bushings that could cause this?

[260zCaliCar]

do you mean the front wheels bounce (as though they are out of balance), or does it feel like it wants to turn and you need to keep pulling it back?

[LowCarbZ]

That's the first place to check is worn out bushings. Could be anything really. Bearing, bushing, tie rod end, wheel out of balance. You'll just have to check each piece. No real way of just making a hazard guess of what it is.

Personally I had a bit of a shimmy in the steering wheel at speed that was caused by worn strut rod bushings.

[jmortensen]

Ball joints and tie rod ends are the first culprits to check. Then bushings. Bushings are a pretty big job if you get a "master kit", search here and you'll find lots of tips that will save you time and effort, especially in the rear control arms area. Hint: spindle pin puller.

[Mr Camouflage]

I just bought a '73 240Z with tokico shocks and eibach springs but whenever I get onto the freeway and exceed about 60 mph, the ride gets reaaaally wobbly and twitchy.

Is there anything besides worn out bushings that could cause this?

Yep, lack of front spoiler will cause this.

[bobc]

Check your bearings and make sure they are set properly. 240Z's have to have the front bearings set just right, or you will experience a shimmy.

[Carl Beck]

The first things I'd check would be the wheels/ tires, followed by front end alignment.

Only the toe is adjustable, but if it's out ie. 0 to negative it will cause the car to wonder/hunt. This can be even worse with wide tires.

These is also the possibility that a strut is damaged/bent or other damage to the front end has been done - throwing off other alignment settings...

If you have a good front end alignment shop - they will check the condition of the front end parts when they do the alignment. Alignment can not be made correctly with worn parts...

FWIW,

Carl B.

[260zCaliCar]

Thanks Carl, you confirmed my first thought which was wheels/tires. When I got my classic car insurance and they limited my driving to 3000 miles a year I went out and bought cheap new tires. Immediately the car seemed to have a mind of its own (like he says, wobbly and twitchy). When the guy mentioned that he just bought the car, the thought ran through my mind that the PO put new tires to make the car easier to sell.

Misturmoneybags never answered my first question so I never posted this logical jump (my other initial thought was tires out of balance which is why I asked for further clarification of the symptoms), but it would be interesting to know if his Z has new tires, and if so, what.

[nahurry]

my z did the same thing but only at slower speeds. i have a front air dam, new ball joints, tie rods, eibachs and tokicos. everything in the front end is new with urethane bushings, but the steering wheel still shimmied. even had the wheels checked and rechecked. only when i went to a 15" konig wheel and new tires did the shimmy stop. now it's as smmoth as silk.

[misturmoneybags]

Sorry for the late reply.

260zCaliCar -- yeah, the car does feel as if its trying to turn and I constantly battle with the steering. The tires may be the problem as well, because the PO mentioned that he had put on some new tires.

Thanks for your help everyone! I'll be taking the car to a shop specializing in Z's, so hopefully they can pinpoint the problem

[mgood]

Sometimes the wheel can be out of round and not caught by the tire balancing. I had this problem with a front wheel for 31 years, always had a shimmy at around 45 to 50 and would go away after that. I kept the wheel and moved it to the back from the front and the shimmy when away.

[beandip]

If you have checked the bushings and what the others have mentioned. You may have a wheel/tire problem. I bought a set of 15'' mags from a friend of mine and they had 225/50X15s mounted . Falkin tires and they were is good shape. I put them on my 240 and it was all over the road when I was on the freeway. Here in northern Ore. people run studded tires in winter and they will groove the roadway. These tires would hunt for a track and were vary squirrelly . I had only bought the wheels not the tires, but decided against using either . I sold the wheels and gave him back his tires and went back to my original turbines. My car is solid at speed now. I do have and had when trying the wheels, new struts and Euro stage 1 springs+ I lowered the car all around. This made the biggest difference.

Gary