If you feel it in the seat then it is coming from the drive train. Check drive shaft, half shafts, diff, mounts, etc. While cruising at highway speed when the vibration is there take it out of gear and see if it goes away or lessens.

Hi Bart,

The vibration problem is one hell of away to fast track your restoration.

All jokes aside. If another set of wheels (mine;)) don't fix it, then I have no idea what will. It can't be in the engine or gearbox because you would feel that at lower speeds in the lower gears with the same revs and you have changed just about everthing that rotates.

Chas

I bet it's the wheels/rims to ! I'm going to try yours..

It looks like radial runout tire or rim

Hey Bart, I was just reading a blog at White Head performance and it mentioned `typical brass bushing wear``at either end of the steering rack which can cause wheel shimmy at highway speeds, perhaps this is your problemÉ FWIW

mark

I allready tested yesterday with the new rebuild steering rack, slight difference but not much. I also read their site, and thought that could be it, that's why I let a shop rebuild the steering rack..it had to be done anyhow.

@ rcb280z: allready tried that to, in our out of gear no difference !

Those vibrations / shimmy's are a PITA to find sometimes. Mine is about 95 percent gone and is one of those shimmy's that come and go. I'm just living with it for now. Went through the "rim repair" scenario etc, and nothing completely fixed it. Am curious to see what you find.

I just picked up Chas wheels. I'm going to try them tomorrow on my Z and find out if this is the problem !

Hey Bart. I once had an annoying bouncing in my 240, and the tyre shop traced it to four poor quality tyres which were impossible to balance. The inside bead of the tyre was not true with the tread area, resulting in a tyre that moved up and down when rotated. Tyre brand FALKEN. I could have named them something more appropriate.

I kicked myself for buying cheap.

Brian.

Edited April 5, 201410 yr by olzed

Problem found... chas's wheels solved the problem, it was not even aligned yet, but a steady ride finally..

now I know where to look, possibly other new rims and bolts..

Thats great.

Yup. I have been looking for classic 14 inch wheels, but it's going to be hard here.. I've called a dozen shops allready, but none seem to have.

See if you can get a new set of American Racing Ansen Sprint wheels. They are one of the makers of the "original" dealer add on wheels (like on your car), but now they make them in 15" instead of 14". They were reasonably priced over here in the US at least.

I've had them on my Z for a number of years now and they are great.

Doug

Bart,

It sounds like you and I might have the same problem. To solve my vibration problems I put on new tires. I took it around to a few tire shops and most said the same thing: Putting new tires on it should take the shaking out of it. And it did! I was amazed!

I'm only saying this after reading so many of the above posts... as I remember, your tires are older? 2002 if I remember correctly. It might be something to consider, especially if they are older and you would be replacing them at some point anyway. Hope this helps...

SoCal-280zx

Bart, Take the wheels to a tyre speacialist and ask them to remove the tyre and check the wheel for run-out on a tyre dalancer. You can rotate it by and check it against a dial indicator or screwdriver. Something to give you an idea if its bent or out of shape. If he doesn't see any run-out, remove all the weights and let him check the balance. If the balancer reads perfect, and I mean perfect because the balancer not so accurate on a light wheel. He will need to set it up for a 12" wheel to compensate a little for no tyre.

I would then try a new set of tyres.

You are looking for another set of 14" rims so if this doesn't work you can use the new tyres on them. I think its worth the gamble, if you can test the rim first.

Goodluck

Chas