260Z suspension query - springs & shocks

[gilltech]

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.

[Cozza]

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

[C.A.R.]

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

[d3c0y]

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.

[Scottz]

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.

[44014]

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

[d3c0y]

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

[gilltech]

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.

[Riceburner]

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

[PB260Z]

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

 

That would depend on the inspector 

[gilltech]

Exactly Gareth J, that's what the tech guy suggested.

But it's a matter of finding an equivalent one about 15-20mm shorter.

[Cozza]

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

 

[Roberto]

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

 

 

[gilltech]

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.

 

[cracker]

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

[Roberto]

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?

[gilltech]

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.

 

[dat2kman]

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.

[gilltech]

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.

[Riceburner]

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.

[Dan260Z]

FWIW, I got the following info from King springs (cut and paste from the guy's email):

 

KDFL-04  175lb Low 260Z Front

KDRS-09  175lb Low 260z Rear

KDFS-04  180lb Stock height 260z

KDRS-05  175lb Stock height 260z

 

Also - if I understand this, most people are reporting "low" springs "raise" the car?  In that case what's the point of using them? 

 

Man nothing is easy with an S30!  I'm literally at the stage of cleaning up and reinstalling the struts on my '74 2+2, and I have no idea whether to use 260z kings lows and full length 260z KYB's... or shorter Z31 KYB's spaced down and cut springs?  Custom Kings? ($$), some other brand of springs?

 

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?).

 

I was about to sell them and just buy 260z versions and king lows... until I read this thread...

[gilltech]

FWIW my conclusion is that the replacement springs I bought - the 'low' versions - are a little too stiff and the fronts are also physically too short.

The back end on my car is now slightly higher (10mm??) than on it's old original & 40-yr old tired springs. But acceptable, especially if they settle down a bit with use.

The front end is also slightly higher than before (15mm??) with the car sitting down on the springs. But with car raised & suspension at full droop the springs are not captured, so not acceptable; so either I find a shorter strut insert, or find softer/longer springs, or re-use my existing springs (re-tensioned perhaps).

The 'standard' versions which have the same rating would push the car even higher, so I can't see how they would be usable.

I haven't decided which way to go as yet.

 

[Dan260Z]

Let me know if you end up selling the king lows - I haven't decided yet either which way to go, but I may be able to use them as I have a set of Z31 shocks that should reduce the drop on the front by about 5-8mm (more if I take the perch off the bottom of the shock and space it down further).

 

Stiffer actually sounds good to me as mine will only be a weekend car - but yeah I'm still curious about the raised height.  My calcs on the standard (OEM) springs I have suggest they are the same rate as what King supply (for both lows and std), so in theory we have same rate as OEM, only shorter - should equal lower.  Perhaps the 2-seaters have lighter OEM springs given they're lighter?  (I have a 2+2)

 

If you're interested, ping me the Spring diameter, wire diameter, free length, and number of coils and I'll try to work out if the OEM 2-seater springs are softer than mine.

 

Also as a side note I measured my FRONT struts last night and they also appear to be about 290mm between the perches - so with the 280mm springs they'd also be non-captive - but perhaps using the shorter z31 shocks I can keep them captive.

[Dan260Z]

Or if anyone is interested in calculating it themselves:  http://www.acxesspring.com/spring-calculator.html

 

I got around 190lb for the stock 1974 260z 2+2 Fronts, tad higher than what King advertise but I may have chosen the wrong material (or perhaps mine aren't stock?  They're dirty/black but on some chipped areas they appear to green or blue underneath.  They measured around 330-340mm long free)

[gilltech]

Dan260Z, FWIW my originals measure about the same length, which is down on stock according to my Nissan manual. If you have one to hand you'll see that factory spring lengths & rates varied quite a bit depending on sales market, if A/C fitted, standard or firm option, 2-seat or 2+2, etc.

 

If yours are blue underneath the black then either someone painted them to make them look pretty or they're aftermarket.

I suspect a lot of Zeds by now have had new firmer springs installed at back to reduce the typical acceleration 'squat'.

 

On mine the new rears will be fine but the lack of 'capture' on the fronts is not acceptable, & I'm not prepared to wire them in place. I think a 20mm?? shorter strut insert with suitable spacer underneath would be best but I haven't investigated the matter any further as yet.