Advise on suspension needed

[docjim]

My(late 74) 260z has had the top chopped off to make it into a convertible (still haven't figured out how i'm going to do the roof) and now has a GM 350 and a Camero T5 installed.  it's a beast to drive. 

 

anyway, here's my problem.  I decided to go with the original suspension, so I go new KYB strut inserts and found used springs.  the alignment shop says the springs are sagging so much they can't adjust the camber.  plus, the ride is really jarring going over the slightest bumps.

 

I've seen springs advertised on EBay that are supposed to be replacement springs for a 260Z, but with the changes I've made to the car, I don't know if they would be any better.  I'm trying not to go the coil over route to keep the cost down, but just want something that's a little less jarring to ride.

 

Suggestions?

 

Thanks

 

Jim

[jhm]

http://forums.hybridz.org/topic/117631-new-s30-shock-and-spring-option/?hl=stagg

[loganpratt22]

I have a set of stock 260Z (1974.5) springs that I am replacing with Eibachs if you're interest in them.  They're on the car currently so I can send pics of the ride height so you can see that they're still tip-top.

[JCan]

Jim.

 

my son and I just restored a '72 204z and have been tweaking many aspects of the car.  

 

With respect to suspension, do you plan to drive yoiur car on a track or on the street?  If you are planning to run your car on the street, I suggest you go directly to coil overs and purchase bilstein shocks. this company ->  https://technotoytuning.com/nissan/240z/four-corner-weld-coilover-kit-datsun-240z makes a great kit and is priced very well.

 

Our first suspension used tokiko shocks and springs, was way too stiff;  our second suspension uses eibach shocks and springs and it is still way to stiff.  

 

The primary reason the car is stiff is because when you lower the car the stock strut configuration is almost completely bottomed out.  Therefore the springs have to be very stiff.

 

This is why I suggest going to the coil overs and using bilstein shocks.  When you manufacture the coil overs you can decide what ride height you want and ensure the car sits exactly at the ride height you want yet has lots of travel both in compression and expansion.

 

Either way, what I am suggesting is a lot of work, but the work is fun and you will experience the benifits of your work every time you get in the car.

 

Best of luck

 

Jim

[docjim]

Thanks for the input.  This is just a cruiser--I can't afford to race it (plus at my age, my reactions are way too slow).  

 

If I can help it I would prefer to just change to brand new springs.  I've replaced the springs with used ones (260Z) twice and both sets sag.  I know coil overs are probably the best solution, but that's a lot of work that I'm not sure I can do (I don't weld).

 

The problem is I would like to put on springs that will give a decent ride without bouncing on every road imperfection.  Plus, with the heavier v8 up front, I don't know what spring/coilover will give me what I want.

 

PS  I'm happy with the stock ride height.

 

Jim

[jhm]

If I read your comments correctly, you want to maintain stock ride height and you want a comfortable ride (i.e. nothing too stiff or harsh) and you don't want to switch to coilovers.  And the springs you've tried to date sag too much for you....do they sag in the front, the back, or both?

 

It sounds like the only real solution is to find springs in stock length and rate, correct?  Unfortunately, most of the aftermarket springs available will lower the car and have a slightly stiffer spring rate.  Coilovers will allow you to choose any ride height and spring rate you want.  Or you can keep trying to find OEM springs that aren't sagging.  Probably not the answer you were looking for.

 

The KYBs may be part of your problem in ride quality....good shocks will go a long way towards giving you a smooth and controlled ride.  Stagg and Tokico (HPs or Illuminas) are just a couple examples of what's available.  KYBs are an inexpensive replacement for OEM that many people find lacking.

 

Finally, I don't understand the statement "the alignment shop says the springs are sagging so much they can't adjust the camber".  ???  Unless you're running camber plates, adjustable camber control arm bushings, or some other specialized equipment, you're not going to be able to "adjust the camber" at all.  The stock suspension mounting hardware does not allow for camber adjustment.  You may want to find a different shop to take your car to....just a thought.

[RebekahsZ]

What size coat and pants do you wear?

[NewZed]

GM 350 and a Camero T5 installed.  

 

 I decided to go with the original suspension,

so I go new KYB strut inserts and found used springs.

the springs are sagging

replaced the springs with used ones (260Z) twice and both sets sag. 

, the ride is really jarring going over the slightest bumps.

 

the changes I've made to the car, I don't know if they would be any better.

 the coil over route to keep the cost down, but just want something that's a little less jarring to ride.

 

Lots of generality and not much hard fact to go on.  Kudos to those that tried but they're all shots in the dark.

 

The SBC isn't that much heavier than the L6 although people think it is.  An SBC with aluminum heads is lighter than full iron.  No numbers at all on the ride height.  Take a measurement.  Tires have a huge impact on ride quality.  The popular low profile tires are harsh.  There are two types of 260Z bodies, early and late.  They use different springs.  Which body style do you have?  "Coilovers" will only allow ride height adjustment.  You'll have the same harsh ride if you don't get the right shocks, and springs, and bump stops, and set it all up right.

 

Get some facts on what you really have and post those.  A picture would help too.  

[docjim]

Wow!  Your questions have shown me how naive I am about suspensions.  However I will try to answer them.

 

Ride height:  I didn't know where to measure since there is an aero fiberglass piece as a side molding and the frame has added metal on the bottom, so I measured using the only original sheet metal I could find--The piece of sheet metal that contains the jacking points for the trunk jack.   It measures 6" at the front and 6 1/2" at the back from the ground to the bottom of that piece.

 

The engine in a 1975 code block with steel Edelbrock heads and intake manifold.  It's pretty heavy.

 

The tires are Yokahams that Discount tire said has decent traction and good ride.

 

I had the alignment done at a Nissan dealer (which may or may not have been the best choice) and they said the caster out of spec bu more than 1 degree.

 

I'll try to add pictures in a separate post.  

 

From what I'm gathering, the best quick fix is to leave the springs as is and get better shocks?

 

Jim

[docjim]

 

The car:

 

 

 

Where I measured (not a very good picture)

 

Jim

 

[NewZed]

That helps.  I was really looking for tire dimensions, not brand, but the pictures show a "normal" tire, probably 70 series.  Ride height does not look that low.  One thing you might clarify is if you mean factory-spec. ride height or what you have now, when you say you're happy with the stock ride height.  Because if the springs are sagging, you're not at the spec. ride height, you're lower.  Do you plan to keep those tires?  If you don't you might get the new tires before going too far.  They might change things.

 

Also, you said camber in the first post, but caster in the last one.  The only thing that's adjustable though is toe so doesn't really matter anyway.  Unless you have adjustable camber plates.  If you do have adjustable camber plates, even though you don't have adjustable spring perches, there might be other changes to the strut mounts.

 

I might be complicating things but it's not clear what you're dealing with.  Your car's been modified and there are a variety of changes that could have deviated from stock late 260Z.  People do strange things once they start cutting and welding.

 

Anyway, the shop's comments about alignment can't really be acted on easily.  They're just observations.  So you're left with a car that looks right (if I read your comments correctly) but has a harsh ride.  So, tires and shocks, and spring preload are the three main things to consider.  The KYB's are generally considered to be a mild, OE-type shock.  They don't get much softer.

[JCan]

My two cents.

 

I suggest you go back to stock springs and use the KYB shocks.  To level the car, you will have to add spring shims in the back, (if it is not too bad add large washers in between the shock tower and the strut assembly you can get 1/2 inch), they are inexpensive and work well.  Your resultant ride will be what you are looking for (as the spring rates will allow the car to move, and the shock will dampen the movement more aggressively than stock).

 

Regarding alignment.  Your car must be aligned properly.  Find an alignment shop that does 240zs.  They will know how to stretch metal in order to adjust your alignment.  In San Diego I used Roger Daniels 8517 Ablette Rd Santee, CA 92071 (619) 562-7969.  If your car can not be aligned then there is something wrong with your body, either way, the solution is to stretch metal.

 

However, before you do that, I suggest you purchase good sway bars front and back and a tension and compression kit for your front suspension.

 

Best of luck.

 

Jim