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gilltech

260Z suspension query - springs & shocks

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Gareth, I ended up getting a set of Z31 KYB (just GR2's) from Baz - I measured them as being only 5-7mm shorter than stock at the front - haven't tried the rear yet (possible the 30mm you mention was the rear?).

 

:-\ Not sure what's going on there, here's the body length on mine. I would've thought the rears would be longer than fronts, I'll see If I have the part number from them.

post-1489-144023749882_thumb.jpg

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OK so I've bit the bullet and decided to section the fronts on the weekend...  with the roughly 6mm shorter Z31 shock and by removing a further 5mm from the bottom of the shock's little perch/foot, I was able to section the strut by 12mm (with 1mm of crush on the shock to hold it in place in the gland nut inner taper).  Hopefully that allows me to keep king lows, cut stock springs, or some other spring solution captive (with the added benefit of adding some suspension travel).  Any more and I would have needed shorter shocks or to lose the shock perch/foot completely, which I preferred not to do.

 

Haven't measured the assembled length yet between the spring perches but will let you know once I do.

 

 

Also meant to measure the KYB Z31 GR-2's for comparison to the AGX's over the weekend but forgot - will try to do so this week.

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You seem to be making good progress Dan260Z.

But what I don't get is why these aftermarket springs are the length & rating they are. I mean, according to my Nissan manual the factory RS30 spring rates could be anywhere from 103 lb to (IIRC - manual is not to hand) about 115 lbs or so. All depending on market, standard or hard, A/C or not, 2-seat or 2+2 etc.

So why are the so-called replacement 'standard' springs up at 175 lbs, & way shorter than stock. IMO a replacement 'standard' spring should be just that, either close to or OEM. And then the 'low' option of about 30mm shorter can be a little stiffer to compensate. Either way they should fit such that the springs are fully captured.

It's all to do with the number of coils over a certain length, the diameter & the cross-section of the wire.

To me the specs of the ones I've bought are just wrong.

So I'm following your efforts with interest, as my front struts still have the original internals & I don't mind replacing them with an appropriate insert if that will solve my problem.

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Cheers... time will tell once I get my hands on some king lows.

I agree though.. it is very disconcerting. Even if I can keep lows captive I've no idea if they'll actually lower my car.. and it'll be years before it's all in one piece and a representative weight so I can find out. Certainly as I progress though I'll keep you posted. Would be great if someone in melb could even loan me some king lows so I could at least let you know if they fit!  And I'm still super eager to run the spring calculator over them and see what rate they really are.

 

The plot thickens further re the z31 shocks.. my kyb gr2/excels are 36cm... longer than Gareths kyb agx's. I have 4x kyb 365056.. supposed to be z31 fronts... perhaps Gareth has rears or a different variant of z31 (eg. turbo/non turbo?)

 

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Heres a pic.

 

Also I discovered the green and blue marks on my springs are just that.. dots that appear to be identifying marks (perhaps to identify them on a production line?). The rest is black through to the metal. My 2+2 had air con and I suspect was originally manual.. and is a DRS30 if that makes a difference. I don't have a manual unfortunately... mind if I ask which one you have and where to buy it?

post-572-144023750322_thumb.png

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Dan260Z, sounds like your springs are factory then. Yes the colour dots will be code for the assembly line. But I don't have a decoder for them like I do for my Mustang for example.

And I doubt if these aftermarket springs will lower your car, IMO they are too stiff for that as they replicate the ride height of the softer factory springs under normal load. Well, that's my finding anyway. And like me, others on here have also found that the 'low' versions don't provide spring capture.

 

I have a hard copy of the original Nissan manual for the 260s, must have bought it well over 25 yrs ago. I see them pop up on eBay from time to time. I've had my RS30 30 yrs later this year. It's in storage, I'm giving it a mech refurb as time permits.

 

Give me your email address & I'll send you my jpg scans of the spring specs pages; I tried to upload them to this post but the file sizes are too large.

I'll also pick your brains regarding the dust boots, mine have long rotted away & I should put new ones on while I'm at it.

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Interesting re. the colour dots.  Good to know at least that I have a factory set to reference in terms of length, etc.

 

In terms of whether the kings lows would lower mine - there is something I could do to get an idea - if you (or someone on here) could provide... rough measurements of

 

- The coil wire diameter

- Coil diameter

- No of coils (inc the squared off end coils)

- Free length

 

...I could calculate the rate.  Then, in theory, if the rate is similar to my stock springs, but the length is shorter, they should in theory lower my car.  As for captive, the sectioned struts should help in that respect.

I'm willing go out and buy a set of lows off ebay, etc but obviously running the spring calc over them first would help justify the purchase given your experiences.

Theoretically going by the rate King advertise (175lbs), adn the shorter length you mention (280mm??) they should lower mine, as my stock springs worked out to ~190lbs on the calculator and are around 330mm long).  Perhaps the 2+2's are a lot heavier...

 

That's be awesome if you could send through the scanned pages... will PM you my email address as soon as I post this :)

 

No probs re. the dust boots, still haven't received them but will let you know as soon as I have them.

 

Gareth have you any info or thoughts re. our differing Z31 shock lengths?  Wish I'd got some as short as yours now as I could have sectioned more out of the front struts and opened up my spring options a lot!

 

 

 

 

 

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For the record I've got KYB 361003s in the rear and 361002s in the front. The springs are what came with the car and are captive at full droop. The car is a 1976 2+2.

Richard

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