280z Rear Strut Spacer?

[chaseincats]

Hi guys,

I was reading that the 280z's rear strut mount was higher than teh 240's and requires a spacer (this part).  If I don't add this to the car, does that mean the front will sit higher than the rear or did the 280z have a rake to it when new?

[EuroDat]

The rear spacers on the US 260Z and 280Z are 25mm longer than the 240Z. You can use the 240Z, but it will lower the rear by 25mm (1"). That spacer in the link will correct it.

I was planning to lower my car by 1". To do that I want to use the 240Z insulators on the rear and lower the spring perch 1" on the front struts. Just have not got around to it yet.

I have no idea why they increased the height on the US version 260Z and the 280Z.

Edited December 4, 2022 by EuroDat
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[chaseincats]

Since they increased the ride height on the rear of the car for the 280 means that when it was sold new it had a bit of a rake to it where the rear was higher than the front then?

[Zed Head]

55 minutes ago, EuroDat said:

I have no idea why they increased the height on the US version 260Z and the 280Z.

I think it was so the bumpers would be at the regulated height.

Found an interesting Hagerty article.  I've also read somewhere that part of the reason for the big bumpers was for insurance purposes.  The insurance companies were paying out too much for minor parking lot bumper bumps.  Can't remember where I read it but it stuck in my brain.  A congressman was involved.  They're called "safety bumpers" but the safety is for the insurance companies.  5 mph.

https://www.hagerty.com/media/opinion/the-hack-mechanic/two-years-that-changed-cars-forever-1974-bumpers-and-75-smog/

[Zed Head]

1 hour ago, chaseincats said:

Since they increased the ride height on the rear of the car for the 280 means that when it was sold new it had a bit of a rake to it where the rear was higher than the front then?

It seems so.  There's overlap though.  Kind of doesn't make sense in light of the 5 mph requirement.  The front bumper is usually hitting the back bumper of the car ahead.  Bureaucratic nonsense.

1976 -

[chaseincats]

1 hour ago, Zed Head said:

It seems so.  There's overlap though.  Kind of doesn't make sense in light of the 5 mph requirement.  The front bumper is usually hitting the back bumper of the car ahead.  Bureaucratic nonsense.

1976 -

Gotcha, so in this case, to have a level car like a 240/260/any other car, the spacer isn't needed.

[Zed Head]

The spacer that the ztore is selling is designed so that they can sell insulators for both small bumper cars and big bumper cars.

What they're saying is if you want a replacement insulator for your big bumper car you have to buy the short 240Z insulator plus the spacer.  Because the "correct" insulator is NLA.  They should really call it an adapter.  It adapts the short 240Z insulator for use in the 280Z cars.

Seems really expensive for what it is.  The specs are probably way too precise.  It looks like a wheel adapter.

[Zed Head]

2 hours ago, EuroDat said:

I have no idea why they increased the height on the US version 260Z and the 280Z.

I think that my comments about the bumpers didn't really address the "why" of the struts.  The rear 280Z struts are longer after the redesign of the body.  It might be that the 280Z's have more rear suspension travel than the 240Z's.  Seems like they could have used the same insulators and matched the strut length to it.  Probably an engineer "perfecting" something, or just starting from scratch.

[chaseincats]

14 minutes ago, Zed Head said:

I think that my comments about the bumpers didn't really address the "why" of the struts.  The rear 280Z struts are longer after the redesign of the body.  It might be that the 280Z's have more rear suspension travel than the 240Z's.  Seems like they could have used the same insulators and matched the strut length to it.  Probably an engineer "perfecting" something, or just starting from scratch.

It sounded like from your post/the fsm pic that adding their spacer to get back to 'stock' ride height for the 280 gave it a rake out of the factory where the body was higher in the back than the front and not using the spacer would get you/us a level-sitting car, no?

[Zed Head]

Well, there's bumper height and then there's body level.  I guess rake might be measured by wheel arch gap?  Don't know.  It's a visual thing.

As far as the Zstore product, it actually lowers the rear end by 0.05", by their own math.  Unless "nearly" means 0.05".  3/4" = 0.75".  (They really shouldn't be mixing measurements like that.  Pick one and stick with it.)  Or maybe "about" means 0.05".  Who knows.  Nearly, about, 0.05", 3/4 inch, 18mm.  18mm = 0.071".

https://www.thezstore.com/product/5532/rear-strut-mounting-insulator-adapter-kit-9-74-78-260z-280z

"Description:
Nissan discontinued Rear Strut Mount Insulators for 9/74-78 260Z & 280Z many years ago. The Front insulators were the same height from 70-78, and are still available, but they are nearly 3/4" shorter than the factory late 260Z & 280Z rear insulator. 

...

These adapters, when fitted to the factory front strut mount insulator and installed in the rear of a 9/74-78 Z-Car, will raise the rear by about 18mm (about 0.7") compared to the front insulator alone,.. "

[Zed Head]

3 hours ago, chaseincats said:

Since they increased the ride height on the rear of the car for the 280 means that when it was sold new it had a bit of a rake to it where the rear was higher than the front then?

I reread your post and the Zstore page and see how they have confused things.  It looks like what they were trying to say is that their new spacer plus a short insulator is "almost" a match for the original 280Z tall insulator.  Kind of poor writing.  "will raise"..."compared to the front insulator alone".

They should have just called it a "short insulator adapter".

"These adapters, when fitted to the factory front strut mount insulator and installed in the rear of a 9/74-78 Z-Car, will raise the rear by about 18mm (about 0.7") compared to the front insulator alone, effectively replacing the original taller rear insulator (or restoring height for those who installed a shorter option previously)"

[Zed Head]

I'll bet a person could just make a solid "donut" of metal or plastic and extend the short insulator studs to make a much cheaper adapter.  The donut takes the compressive forces and the standoff nuts and studs take the tensile.  Should work.

https://www.mcmaster.com/standoff-nuts/

https://www.mcmaster.com/studs/

Edited December 4, 2022 by Zed Head