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260Z suspension query - springs & shocks


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#1 gilltech

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Posted 01 April 2014 - 10:46 PM

Just picked up a full set of 'low' option popular aftermarket springs for my 260 to replace the tired originals.
'Low' option is 30mm shorter than their 'standard' (the latter intended to maintain original ride height).
The rears seem fine, but the fronts are only 280mm high & don't engage with the retainers at top when suspension at full droop, I'd say they're about 12mm short.

My tired originals are 335mm, factory manual calls for a range of heights between 341.5 & 395mm depending market, 2 or 2+2, standard or hard suspension, A/C etc.
And my 260 already has the shorter of the 2 types of '74 260's strut heights.
Anyone else struck this issue?
The manufacturers have been most helpful but can't shed any light on how their R&D came up with those lengths, other than they worked off an actual car.

Clearly I can't use the 'low' springs as they are as they wouldn't stay in place, & the longer 'standard' ones will lift the front up 30mm which would pitch the car nose-high. Both options are 175lb.
I either give up & refit my original springs, or find shorter cartridge inserts (happy to replace them). Anybody done this & know what worked?
Thanks in advance.

#2 Cozza

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Posted 01 April 2014 - 10:58 PM

Yep I found the same thing when i bought "low" king springs for my 240. Part numbers KDFL08 and KDRL09.
Both front and rear are non captive by about 5mm. I used cable ties round the bottom spring perch to the bottom of the spring and again cable ties round the top hat to the top of the spring. I know its not ideal but i have driven about 1000 odd k's since installed and no probs as yet.
I know some others use tie wire instead.
On another note, I have found the fronts did not drop the ride height by the suggested 30mm. I'm interested to find out how your ride height works out.
Mick

#3 Lurch ™

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Posted 02 April 2014 - 06:23 AM

Early Zeds have a massive amount of droop (from static ride height) compared to bump travel (from static ride height).
So as you lower a zed with lower springs, the springs can move out of the spring perch.

I've never worried about the shorter (lower) springs falling out when driving (they never will),
but as Cozza has stated just use some heavy gauge hi-tensile tie-wire to tie the springs to the perches if you're worried ;)

#4 d3c0y

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Posted 02 April 2014 - 09:21 AM

My car has KDFL08 and KDRL09 and i've never had any issues with them, but i don't jump it.
You don't need to worry about it.

#5 Scottz

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Posted 02 April 2014 - 09:45 AM

Yep - wire the spring to the perch.
Unless your rally driving you will probably never get enough droop to allow the spring to come free of the perch anyway.

#6 44014

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Posted 02 April 2014 - 11:33 AM

I get a wheel off the ground every time I go up my driveway...

#7 d3c0y

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Posted 02 April 2014 - 12:17 PM

Your drive way is verging on a cliff face though and you cut your springs so your car has no travel when loaded...

#8 gilltech

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Posted 02 April 2014 - 01:30 PM

So no-one's had any problems when getting a road-worthy check?

Cozza, as for my ride height, I'd say the car is maybe 12mm higher than originally with my old springs, which would be quite a bit softer than the new ones.
The back also looks a touch higher, I replaced them first & duh never thought to measure the original height first. I think I'll go back & measure it all up before/after.
So I won't be throwing my old springs away; I liked the car's original stance & ride-height & I'm not really wanting to raise the car so looks like I've got a bit of thinking to do about all this.

Thanks to everyone for your input.

#9 Gareth. J.

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Posted 02 April 2014 - 01:41 PM

Run a shorter shock, it will limit the amount of travel at full droop and keep the shorter spring captive the whole time.

#10 PB260Z

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Posted 02 April 2014 - 05:36 PM

So no-one's had any problems when getting a road-worthy check?


That would depend on the inspector  8)

#11 gilltech

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Posted 02 April 2014 - 06:45 PM

Exactly Gareth J, that's what the tech guy suggested.
But it's a matter of finding an equivalent one about 15-20mm shorter.

#12 Cozza

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Posted 02 April 2014 - 07:03 PM

This is a little off topic but it does pinch my nerve.
From what I read of posts on this forum regarding King Springs, I don't think I have seen any 2 posts stating the same information the King tech department have given them.
I have been quoted by the tech dept. the following spring rates:
KDFL08 280 lb/"
KDRL09 320 lb/"

I have read all sorts of conflicting rates for these springs on here. Is this just bad info from supplier or something else?

Sorry for the rant but it does bug me.
Mick


#13 Roberto

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Posted 02 April 2014 - 07:44 PM

The tech dept. is dreaming.  Those rates are very stiff for the street.

The correct King Spring rates:

KDFL-08  305mm 100-170lb (progressive) FRONT
KDRL-09  285mm 175lb REAR



#14 gilltech

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Posted 02 April 2014 - 08:23 PM

Roberto,
Thanks for info. But the 240's struts are taller than the 260's, so those springs you quote will surely be too short to achieve full spring retention?
Cozza,
Yes this bugs me too, I was expecting a simple replacement & associated upgrade but its not working out.
Look I really appreciate the suggestions as to what others have done & I can understand the reasons but I'm just not comfortable with wiring the springs in place. I'd rather install slightly shorter strut inserts, it's time they were replaced anyway, but it's a matter of working out which ones.
Thanks everyone.


#15 cracker

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Posted 02 April 2014 - 09:08 PM

I have also received the same information as Roberto quoted, direct from king springs. (They were quite forthcoming with info)

I decided to go with the 160lb (f&r) Lovells springs as I wanted linear rates f&r. They are also supposed to drop the car by around 30mm but I believe they have actually lifted slightly. (I didn't measure sorry)

It would be relevant to note that I combined the springs with the "factory replacement" kyb gr2 struts, which wouldn't help trying to drop the car.

EDIT: To clarify, my car is a 240z

#16 Roberto

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Posted 02 April 2014 - 10:14 PM

Roberto,
Thanks for info. But the 240's struts are taller than the 260's, so those springs you quote will surely be too short to achieve full spring retention?
Cozza,


I have an early 74 260z fitted the 240z low king springs and my springs are completely captive at full drop or when struts are disassembled from the car.  Does that help?

#17 gilltech

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Posted 02 April 2014 - 11:04 PM

Roberto,
My car too is the 'early' '74, so it originally had the 240-style front struts like yours but one was damaged when I bought the car nearly 30 yrs ago so I eventually substituted the later-260 type pair from a parted-out car which are slightly shorter & thicker, & installing them therefore dropped the front a little which was a good outcome.
I'm picking the springs you used wouldn't be captive by very much? And what's your ride height like?

So for my car at least I conclude that the 175lb rate is too high for the fronts as resultant spring ends up too short & I'm not keen on wiring it in place. So either I find a taller & softer spring so car settles down to a nice height (Cracker used Lovells at 160 lbs), or I find a shorter strut insert, or I give up & stick with my original front springs maybe have them re-tempered & reset. The new low rears are entrapped just fine, ride height is raised slightly but I can live with it.


#18 dat2kman

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Posted 03 April 2014 - 02:22 AM

As long as the spring is physically captured by both top and bottom spring perch/seats, you will not have any issue, both with driving and inspections.
On 260 struts for circuit use, the spring perches can be repisitioned 20-30 mm lower, rewelded on, lower height linear rate coils, (270 lb or higher) and, rather than tie wire or cable ties, a pair of small metal tabs, welded to edge of spring perch, and eased over the seated coil, is pretty well foolproof.

#19 gilltech

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Posted 03 April 2014 - 09:38 AM

If I had a machine shop I could probably re-work & shorten the damper rod at the threaded end.
I think it best I find a shorter damper insert, it's time they were replaced, maybe I'll contact Monroe & see what they have in their range.
Not a simple bolt-on exercise after all!!!
But thanks guys.

#20 Gareth. J.

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Posted 03 April 2014 - 09:52 AM

I use KYB's from a Z31 300zx, IIRC they're about 30mm shorter than stock shocks so youd need a spacer on top. Total length is approx 340m, I have the AGX 4 way adjustable type, similar to the Koni yellows. I guess they are probably available in the base model GR2 gas which should be ok and cheaper. The 240z inserts have a 'D' shaped thread on top, the Z31 type have a 14mm round top so you'd need to drill the top insulator too.




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