Early 260Z Stock Ride Height

[oldhemi]

Nissan raised the height of the rear by 1 - 1 1/2" to the best of my memory in 1974 to help some high speed stability. I never liked the look. I put on Mullholland springs and shocks in '77 and that lowered it too much. I would like to get the same stance as the stock 240z's and I am asking if anyone knows what I gotta do.

I still have the original springs somewhere, I think. IIRC, all 4 springs have the same color coded tape on them - meaning that they are all the same spring rate I would guess.

I dont want to cut the coils. IIRC, the local auto parts places list the same spring for the 240Z and 260Z which I know is wrong. Are there correct 240Z rear springs that I can substitute? Or, as I saw in some thread recently, did Nissan accomplish the deal by substituting thicker top insulators?

Also, I can no longer take the stiff ride of the springs/shocks. What are some gentle brands of shock cartridges out there?

Thanks for any input/opinions/comments.

[geezer]

Different springs were used on the '74.5 & '75 models. Here is a comparison of dimension specification chart covering '74, '74.5 & '75. The insulator design changed with the '74.5 model, with an increased height of .79".

Can the dimensional specs for the 240Zs be found to make a comparison?

Edited December 18, 2009 by geezer

[oldhemi]

Thanks Geez! Interesting numbers on the chart - can I ask you where this chart can be found? The insulator pic should also be helpful to 280Z folks.

Like you posted, now I (we, if anyone else is interested) need the 240Z equivalent. I am going to hunt through some old boxes this weekend which might still have some info concerning the spring color codes that was in the parts boxes with the springs. I know that it is not factory documentation but it might be helpful for any other historians here.

Edited December 18, 2009 by oldhemi

[geezer]

I found this chart & the insulator illustration in the 1975 Design Specifications manual. It is a good manual, showing the differences between early and late 260Zs and the transition to the 280Z in 1975. The spring specs can be found in the FSMs for each individual year of the 240Z. If no one beats me to it tomorrow, I can dig up this info.

[geezer]

The FSMs can be downloaded here.

http://www.xenons30.com/reference.html

Here is the relevant information:

'73 240Z.......................................................................'74 260Z (early)

11.4mm (0.449in)...............Spring Wire Diameter...................11.5 (0.453in)

100mm (3.94in)..................Spring Coil Diameter....................100mm (3.94in)

10.65................................Number of Coils.........................9.25

369mm (14.5in)...................Free Height...............394mm (15.51in)

215mm (8.4in).....................Installed Height...........221mm (8.70in)

288kg (635lb)......................Normal load.............................705lb

1.85kg/mm (103.6lb/in).........Spring Constant...1.85kg/mm (104lb/in)

Edited December 18, 2009 by geezer
fixed mistake

[oldhemi]

Thanks for both bits of info! And, I apologize for not searching harder for the online manuals. I have downloaded EVERY manual up to the 260Z manual and been studying.

So, I look at the data and I see that it appears that the early 260Z was only.3 inches higher in installed height. It seems to me that the car sat at least an inch+ higher than 240Z's. I also see that the 260Z springs have a higher weight capability which is good because me and the mizzus are no longer svelte 20 somethings:)

I guess that I will have to look at aftermarket springs and shocks. Not sure if there are new 240Z springs available. I just can not take the bone-jarring setup that I now have.

I am seeing that KYB and Tokiko(sp) are the front runners for cartridges? I am hoping to hook up with some local Zhedz and see if ZI can get a ride in their cars with various setups. Meanwhile, I am busy poking and prodding the rust.

[geezer]

All this information only gives you the stock configuration which was too high for your taste anyhow. Hopefully it will help you decide what combination of springs & struts to use to achieve the ride quality and height you are looking for. Tire selection, air pressure, bushing material, spring and strut combinations can be best evaluated by asking questions here. Every possible configuration has been looked at I think. Looking at the pictures in the gallery will help too. Good Luck!