lowering spring slop

[datsfun]

Funny you should mention the gauge of the wire, the rear springs seem really soft (then again, they are way too long) and the rear suspension can be compressed easily by pushing down on the rear of the car. Can't really tell either way with the front as they have never had the weight of the car on them and it's hard to tell by just pushing down on the springs.

If you have gone for the standard ( 30mm lower, 15% uprated) set up, then the wire gauge should be thicker on the newer units when compared to factory ?

As for getting the front and rear springs mixed up -- when I first got the springs the two shorter springs had F on them, and the two longer ones had R on them, so it would be pretty hard to mix them up

Hmm, would you trust the spring manufacturer to get this right in light of current issues? On other datsuns where I have had springs remanufactured the front are sometimes longer when compared to rears.

Compare them to original units to be 100%...by that I mean are orig fronts shorter than rears? That should eliminate any mix up theories for sure

It may also be an idea to find someone who has an early 260Z with uprated springs just to compare measurements, especially when not under load...no of coils F&R, wire gauge etc

 

[highway star]

think ive been down this road too. i have an early 260 and bought what looks like the same springs off Mike and had exactly the same problems you're having. i ended up chopping one full loop of the old springs & putting them back on. i was told the lower spring seat on the early 260s were lower than the rest. if you manage to fix it please let me know!

 

[morbias]

aaah information overload

moggy240 - I'm certain now the shocks aren't the issue as the rear springs are too long and the fronts too short, there's no way shock length could cause both those issues, it should be either too long on both or too short on both as the actual shock assembly is the same in both the front and rear, the rears just have a spacer tube.

datsfun - There isn't much difference in length between the original fronts and original rears, I'd have to look again but I'm pretty sure the rears are very slightly shorter, as in a few mm at most. Even if they were labeled incorrectly then I'd still have the very same issues, only in reverse. Also, the problem with finding someone with a lowered early 260z who isn't using adjustable coilovers is slim!

highway star - I've been weighing up my options and am contemplating doing the same... by chopping off one loop then the spring rate of the remaining coils effectively goes up ~10% unless I'm mistaken?

I've been pondering the problem all day long and to be quite honest this is the way I see it right now; there seems to be a lot of confusion relating to strut differences between years and variations in Euro vs US springs. As far as I can tell, the early 260z rear strut is identical to that of the 240z. The front strut is identical to a 240z front strut apart from the fact the lower spring seat is 1" lower down. As for the differences in Euro / US springs... well really who cares? It just complicates matters and isn't significant in the least bit as the springs are being replaced. As long as the differences of the struts are understood then it should be as simple as getting springs manufactured to 240z specifications with the only difference being that the front springs are 1" longer when unloaded, I don't see the point of going through the hassle of having the originals load tested and so on if it isn't a reliable method of coming up with a usable spring specification.

Basically what I think I need;
rear springs = exactly the same spec as 240z lowering springs.
front springs = same specs as 240z lowering springs, just 1" longer unloaded.

Which is pretty much why I am wondering how the hell I have ended up with springs that are ~5" too long on the back and ~1" too short on the front. Clearly the fronts seems to be made to 240z spec, but I've no idea at all what is going on with the rears.

If my logic is flawed then someone please feel free to point out why.

 

[zbloke]

Taking everything into account, I would take the hacksaw to your original springs and chop 1 or even 1.5 coils off.

It will move your project on.

I chopped my springs years ago and was happy with the results, I then aquired some spare struts and worked on a platform adjustable setup so I could do a straight swap over when they where ready.

IMO of course

 

[morbias]

Maybe, but it's not an ideal solution - I'd rather have new uprated springs as I don't know how bad the originals really are and chopping them might just make the ride really bad. If it came to it I would rather just put a 240z spring kit on and put up with the 1" lower front, at the risk of bottoming out now and then, though I've already cut the bump stops down by about 3/4" so it shouldn't happen too often.

 

[datsfun]

Since you have invested in brand new and expensive shocks, why dont you convert the struts to adjustable ride height and use 2.25ID spings instead? This will cure the issues you are facing at the moment and also give you the option to swap springs easily to get your setting spot on.

Weld on threaded kits arent expensive either

 

[morbias]

I see what you're saying, but then I would have to work out where to weld on the new seats and given my luck recently (or total lack of it) I could potentially end up with a much bigger problem.

 

[datsfun]

I see what you're saying, but then I would have to work out where to weld on the new seats and given my luck recently (or total lack of it) I could potentially end up with a much bigger problem.

Nope...if you buy the threaded sleeve type of kit and once you have ground of the existing seat, you simply slide the threaded tube over the now bare strut. The top of threaded sleeve is normally a few mm below the top of the strut, so that you can unsecrew the gland nut and remove insert. tack this sleeve in place and weld away. The threaded sleeve,allows the spring seats to move up <> down by over 4". 2.25ID springs are available in lenghts from 7" all the way to 14" , so no issues about either bottoming out or having slop. Its the only way forward IMHO if you want adjustable ride height and damping

Have a look on the web, lots of articles on how to convert to coilovers. I would advocate the weld on type rather than those held by grub screws or slip on type...

 

[morbias]

The thing is, I briefly discussed weld on sleeves with Pete Mac the other day and pretty much came to the conclusion that it would still be a case of getting the correct spec springs for the application. If you lower the seats then you are not just lowering the car but reducing the compression of the coils; ie. if the springs aren't long enough then I would end up with the same problem of the top of the spring not contacting the top mount.

Anyway, I will look into it a bit more at some point, but not just yet as I have to be up for work in 4 and a half hours and have decided to deal with the rear spindle pins next... right now I can't even get both the locking pins out, I imagine further pain and suffering lays ahead.

 

[Rob Gaskin]

If you lower the seats then you are not just lowering the car but reducing the compression of the coils; ie. if the springs aren't long enough then I would end up with the same problem of the top of the spring not contacting the top mount.

If you lower the seat you will lower the car unless the damper is as low as it will go. That shouldn't happen but if you lower the car a lot with standard length dampers they might bottom on compression (I have shortened struts/dampers).

You buy the correct length spring (lots available cheap) so that on extension of the damper the spring is not loose. The problem is with long dampers you would need soft springs to get it lower when it's on it's wheels. So lowering springs need to be matched to dampers and if you want to go very low, to the struts too.

For a couple of years I ran on standard shocks and 1 coil cut off the spring, however on changing to my current suspension it made a big improvement. If you've got this far get it right now either with 'off the shelf' stuff or coilovers.

 

[Albrecht]

I've been pondering the problem all day long and to be quite honest this is the way I see it right now; there seems to be a lot of confusion relating to strut differences between years and variations in Euro vs US springs. As far as I can tell, the early 260z rear strut is identical to that of the 240z. The front strut is identical to a 240z front strut apart from the fact the lower spring seat is 1" lower down. As for the differences in Euro / US springs... well really who cares? It just complicates matters and isn't significant in the least bit as the springs are being replaced. As long as the differences of the struts are understood then it should be as simple as getting springs manufactured to 240z specifications with the only difference being that the front springs are 1" longer when unloaded.....

I find posts like the above depressing. If the differences were properly understood and recorded accurately then problems like the ones you are experiencing would be a lot more unusual.

Of course the differences between market models matter! Differences in spring seat heights and differences in spring rates, compressed and free lengths for "240Z" and "260Z" models ( those "240Z" and "260Z" names mean nothing on their own ) are the very reason why you and the people trying to help you are confused, let alone the spring suppliers.

The first thing people seem to do these days is look at the USA-based sites for data on springs and dampers, then confuse themselves by believing that the USA-referenced data applies to UK market cars. They also read about so-called "Euro" springs and think this refers or applies to the UK models ( it doesn't! ).

Basically what I think I need;
rear springs = exactly the same spec as 240z lowering springs.
front springs = same specs as 240z lowering springs, just 1" longer unloaded.

See? What are "240Z lowering springs"? It's meaningless!




If you have a UK market 'RS30' 2-seater model ( and/or its 'Q' suffixed variant ) then your ORIGINAL spring specs should be as follows:

FRONT:
( 'Standard' ) Active turns of coil: 9.5, Free length: 384mm, Spring constant: 1.84kg/mm ( 103lbs/in )

( 'Hard Suspension' ) Active turns of coil: 8.5, Free length: 362.5mm, Spring constant: 2.06kg/mm ( 115.4lbs/in ).

( 'Europe' ) Active turns of coil: 8.5, Free length: 362.5mm, Spring constant: 2.06kg/mm ( 115.4lbs/in ).


REAR:
( 'Standard' ) Active turns of coil: 9.5, Free length: 406mm, Spring constant: 1.84kg/mm ( 103lbs/in )

( 'Hard Suspension' ) Active turns of coil: 7.5, Free length: 350.5mm, Spring constant: 2.59kg/mm ( 145lbs/in ).

( 'Europe' ) Active turns of coil: 7.5, Free length: 363.5mm, Spring constant: 2.59kg/mm ( 145lbs/in ).




At least with some kind of datum point you'll be able to figure out what direction you are going in.

 

[STEVE BURNS]

Alan Not that i know diddly as a lot of it goes over my head
but does that mean that the front "hard suspension" and "European" are the same as the spec is the same
And the rear Hard and European end up the same lbs/in even though the spec is different

Please be easy with me as you know I am a numperty on tech stuff just trying to understand

 

[Albrecht]

...does that mean that the front "hard suspension" and "European" are the same as the spec is the same
And the rear Hard and European end up the same lbs/in even though the spec is different

Yes and yes.

On the rears, the 'Hard' and 'European' are the same in turns of coil and spring constant, but the free length is different.

There are several sets of figures for the Japanese market models too, not to mention other market variants.

Lots of subtle differences. And - after all these years - any individual car could have been retro-fitted with anything and/or modified. I always try to have a good look at the stamped part numbers on the strut tubes at the very least....

 

[SeanDezart]

Here endeth the lesson - please give generously on your way out - thankyou.

 

[datsfun]

Morbias, I am not sure that I agree with your analysis of the possible problem arising again when using the 2.25ID springs. I woud measure the open lenght ( base of gland nut to tip where it mounts onto top mount. This should give you min lenght of spring required - free standing at least. Add 2" to that and hopefully you have a good starting point as far as spring lenght is concerned.

As for rates, this is a personal choice...180lb/ft would be a good starting point and easy to change.

I agree with what Rob says that sometimes if you want to go silly low, then there is a chance that shock will bottom out and only way round that is shorter shocks etc.

I have converted nearly 5 pairs of different struts ( non s30) but datsuns all the same over the years and never had issues with spring lenghts etc. Recommended min lenght up front is usually 10-11" ( open lenght)

There are a few people here whose s30's run adjustable platforms...surely they can pass you data of their springs ( admittedly they may different struts but we are looking at max 1" difference? ) This can be compensated by moving spring seats accordingly??

Lots of subtle differences. And - after all these years - any individual car could have been retro-fitted with anything and/or modified. I always try to have a good look at the stamped part numbers on the strut tubes at the very least....

Very important and often over-looked point above. Most cars have been through a few owners, perhaps a few restorations too...who knows if the struts on the car are actual factory spec or have they been swapped in the past?

 

[morbias]

I find posts like the above depressing. If the differences were properly understood and recorded accurately then problems like the ones you are experiencing would be a lot more unusual.

Of course the differences between market models matter! Differences in spring seat heights and differences in spring rates, compressed and free lengths for "240Z" and "260Z" models ( those "240Z" and "260Z" names mean nothing on their own ) are the very reason why you and the people trying to help you are confused, let alone the spring suppliers.

The first thing people seem to do these days is look at the USA-based sites for data on springs and dampers, then confuse themselves by believing that the USA-referenced data applies to UK market cars. They also read about so-called "Euro" springs and think this refers or applies to the UK models ( it doesn't! ).



See? What are "240Z lowering springs"? It's meaningless!




If you have a UK market 'RS30' 2-seater model ( and/or its 'Q' suffixed variant ) then your ORIGINAL spring specs should be as follows:

FRONT:
( 'Standard' ) Active turns of coil: 9.5, Free length: 384mm, Spring constant: 1.84kg/mm ( 103lbs/in )

( 'Hard Suspension' ) Active turns of coil: 8.5, Free length: 362.5mm, Spring constant: 2.06kg/mm ( 115.4lbs/in ).

( 'Europe' ) Active turns of coil: 8.5, Free length: 362.5mm, Spring constant: 2.06kg/mm ( 115.4lbs/in ).


REAR:
( 'Standard' ) Active turns of coil: 9.5, Free length: 406mm, Spring constant: 1.84kg/mm ( 103lbs/in )

( 'Hard Suspension' ) Active turns of coil: 7.5, Free length: 350.5mm, Spring constant: 2.59kg/mm ( 145lbs/in ).

( 'Europe' ) Active turns of coil: 7.5, Free length: 363.5mm, Spring constant: 2.59kg/mm ( 145lbs/in ).




At least with some kind of datum point you'll be able to figure out what direction you are going in.

So are there any differences in the height of the lower spring seats between markets? Because that is all I need to know. If there is no difference, then no, original spring spec doesn't matter to me whatsoever because I can buy an off the shelf lowering kit (the 'meaningless' 240z lowering springs I was alluding to) from Eibach or Tokico or similar and know exactly how low the car is going to sit.

But as it turns out it appears I have 'US' spec springs as the specs match those in the Haynes book of lies.

Also, it doesn't matter which spring specs the manufacturers were going by; none of those specs would result in the rear springs being 5" too long and at the same time the fronts 3.5" too short (yeah, it was really that bad on the first set they sent me - I didn't think it was so big a difference until I went back and looked at the photos). Even after sending my current springs to be tested the replacement rear springs came back exactly the same.

Sorry, but it is pretty clear to me they screwed up on an epic scale and it's not simply a case of Euro vs US spring specs.

.

 

[SeanDezart]

For a couple of years I ran on standard shocks and 1 coil cut off the spring, however on changing to my current suspension it made a big improvement.

Roll on the '80s eh ?

 

[Rob Gaskin]

Roll on the '80s eh ?

Sean, I'm not sure what you are getting at but if you think I'm stuck in the 70s that's because my lovely car (that means so much to me) is a 70s car. I have very fond memories of the 70s my personal favourite decade. That's why I wouldn't put a modern 20xx engine in it.

I've got my 370Z for the modern side of motoring.

What I was saying in reply to Zbloke suggesting cutting a coil off the springs is that it works, no problem but when you upgrade to decent suspension it works even better. Not rocket science but if Morbias has had this much aggro then it may be worth going 'all the way' now.

 

[SeanDezart]

What I'm getting at is that your cut springs were THE suspension mod to be done back in the early '80s, just like truck-weight "4 piston calipers"and vented discs and as you've stated, getting it right makes a HELL of a difference but people didn't look further back then to know better.

 

[Albrecht]

So are there any differences in the height of the lower spring seats between markets? Because that is all I need to know.

YES. Look at post #12 in this thread.

If there is no difference, then no, original spring spec doesn't matter to me whatsoever because I can buy an off the shelf lowering kit (the 'meaningless' 240z lowering springs I was alluding to) from Eibach or Tokico or similar and know exactly how low the car is going to sit.

The point I'm trying to make ( in laboriously typing out all those specs from the factory service manual for the UK & European '260Z' variants ) is that knowing the OEM spring lengths will enable you to understand the springs you originally had. As far as I can see, they are your only positive datum points at this time.

The reason I'm making the point that the term "240Z lowering springs" is meaningless is because there's not one single model of "240Z" and there was big variation in both springs and struts ( strut differences included different length tubes and different lower spring perch heights ). How can you know how to get where you want to go if you don't know where you are?

But as it turns out it appears I have 'US' spec springs as the specs match those in the Haynes book of lies.

I've never looked in a Haynes manual for the cars, but I'm surprised yours lists the "US" spring data. Is it the Haynes manual for the "US" models, then? No wonder you are confused ( and I am too.... ).

So ( unless its a secret ) what are the coil counts and free lengths of the 'original' springs that came off your car, and what are the ( Nissan ) part numbers on your front and rear strut tubes?

Sorry, but it is pretty clear to me they screwed up on an epic scale and it's not simply a case of Euro vs US spring specs.

I wasn't saying it defintely was, just that it's something that should be taken into account. I can understand your frustration, but please don't throw good information, given with good intent, back in the faces of people who are trying to help you.