[68ragtop]

This post could probably go into the suspension tech forum as well, but I wanted to see if anyone can share specific info they might have learned vehicle specific, rather than just a suspension question.

A little background first:

I put my 68 chassis together many years ago, & at the time I ordered new coil springs front/rear I believe from a company called "coil spring specialists"? (I need to see if I can find the receipt) Anyway, they asked very specific questions to get me the right springs. Well, upon first installing them they seemed crazy stiff, in fact the upper control arms stayed on the bump stops. A couple years later I had the car all together for a mock up as I was fitting body panels, etc. The car still sat like a 4X4 front & back. It looked like it had no engine installed.
I then called the spring manufacturer & they assured me I had the correct springs & they just needed to settle down. I get that, they do settle over time. But, it never did. At one point I threw several hundred lbs of sand blasting material on the floors to simulate the interior as that's all that was missing from a weight perspective. no change. Then I put rachet straps on the suspension while it sat on a 4-post lift & pulled it down lower than where it should sit. Left it like that for several weeks. Released the straps & it bounced back up to truck level. So something was for sure wrong with these springs.

So back to my question.

I have the suspension all apart again & I was going to cut a few loops out of the springs to get the car to drop. But I am unsure if I should do that, or just buy more springs & hope to find something that works. I would rather have the car sit a smudge low than too high. Just a personal preference.

Anyway to figure out what the heck these springs are by thickness, height, etc?
I am lost.......

[68ragtop]

I did find a thread I started over a decade ago. Wow, time flies
same springs, same problem. just a much later date........ lol

I am guessing I will try taking some length out of these springs, but Not sure how much to remove. The car sat about 2" too high in the front, possibly even more.

http://forums.maxperformanceinc.com/...springs&page=3

[PurelyGTO68]

My original front coil springs have 9 full coils. Looks like your springs might have too many coils and/or may be too tall. Your rear springs look like mine...

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[dataway]

Bear in mind, if the spring rate is too high, and you remove coils, it will actually STIFFEN the spring. It will lower the car yes, but if the springs are the wrong rate (too stiff) it will be the right height, but the ride would probably be horrible.

Each coil compresses, fewer coils to compress, higher spring rate.

Those things seem to have a LOT of coils ... I could go down and count mine I guess .. but they are aftermarket also.

[68ragtop]

I am just ticked at myself for not pushing the issue when I bought them. Wasn't cutting corners, even paid them extra to have them powder coated at the time. I still have my originals, but like most they are pitted & wouldn't looked good restored. I must have had a picture of them side by side in the old thread, but the picts are long gone.

Is is safe to say most springs use the same steel strength, or would that be very incorrect? I am not sure if I ever measured the diameter of the coils compared to the originals.

[dataway]

Since you still have the originals ... how do they compare in diameter of coils, thickness of coils, number of coils and height ... even though height might be meaningless on used coils.

It's doubtful the height changed dramatically from being used. Otherwise the ride height would have been unacceptably low. Might change an inch uncompressed. Old springs will probably lose some stiffness and compressed height ... but probably lose less uncompressed. In other words they probably get "weaker" but might not lose much uncompressed height.

[68ragtop]

I'll have to go get them. I have a bunch of old worthless parts in storage about 3 miles from my home. I can't tell you how many times I go back there for stuff like this. Just like the endura bumper a couple months back. Its bent bad, but was a great reference to originality.
When this car is done I will be purging a lot of old parts.

I am thinking I must have compared the springs to my originals at one time on that older thread. something was different, I just didn't describe what it was & the picture is no longer hosted. I am having a hard time lately with how many years this car has been apart..

[north]

If you still have your original front springs I'd reuse them. Ames sells 1/4" and 1/2" rubber spacers if they have sagged a bit since new, rule of thumb is the spacer will raise the car by a bit more than double the spacer thickness. For the rear I'd use the standard Ames rear coils (they sit a touch high so if you want a bit lower stance order the coupe ones for a rag top. Stock ride height for a 68-69 is 9.5" front and 9" rear as measured at the bottom edge of the rocker molding. This is with a full tank of gas and the stock G78 tires, If you run G70's or 225-70/14 radials it will sit 1/4" lower.

The convertible still has its original front springs with no added spacers (69k miles and it was ordered with ride and handling option-they haven't sagged at all). Rear are Ames standard ride coupe springs with factory thickness upper insulator.

[nytrainer]

I changed rear springs ('68 conv) recently with the cargo type as the (supposed) originals were tail dragging and bottomed with rear passengers. I like the height with G70's. I don't recall seeing upper insulators though. Did they get tossed sometime in the last 50 years?

[455GRIN]

The front springs I removed from my 69 GTO in 1994 (not sure if original), have 11 coils and are 18 inches tall. The ones I put in, I cut a half a coil or so. Dropped it right where I wanted.

how tall are yours?

[68ragtop]

So I finally picked up my original springs last night. To my chagrin they are nearly identical to the springs I bought. What the heck? Same overall diameter, same coil diameter & oddly they are longer than the replacements I am having trouble with. Are they different temperaments?

.

[dataway]

Without a doubt spring rate depends on what metal is used in the spring. So they can be identical and have different spring rates.

One thing I hate about most aftermarket springs is the fact that one end of the spring is not finished properly. You can see how the OEM spring is manufactured to be flat on the top side so it fits nicely in the frame pocket. The lower side has the tail that fits into the pocket designed to accept it in the lower control arm. Without the flat top end, the spring tries to cock to one side under load.

Easy to check, a front spring should stand up straight, or close to it, on the top end of the spring. I ground down that tail a bit on my springs to get it flatter on the top.

I freakin hate springs ... you never know what you actually have until the car is completely assembled and ready to go ... and if it's wrong, which it often is .... you have to play around with springs ... which is no fun on the front.

Hopefully you can get some feed back from people here that have bought a specific spring, from a specific supplier and can tell you the results.

[68ragtop]

These are ground a little flat on the top, but nowhere near as nice as the originals like you mention. I know springs can be a pain & that was one of the reason I bought from coil spring specialists. I told them my concerns right up front & the sales guy took all the information & at the time I felt I made the right purchase. I remember the phone call well. These were not cheap either. way more than the local parts stores at the time, But I was trying to ovoid the situation I am in right now...... shoulda ordered them for a 250 OHC tempest.

[PurelyGTO68]

Originally Posted by 68ragtop

So I finally picked up my original springs last night. To my chagrin they are nearly identical to the springs I bought. What the heck? Same overall diameter, same coil diameter & oddly they are longer than the replacements I am having trouble with. Are they different temperaments?

.

I am confused why your original springs have 11 coils and mine only have 9? My car is a disk brake car....is your car a drum brake car.....and would that make any difference? (I would think they both would use the same spring all else being equal...)

This is the best photo I could find of my springs. This is the pile of stuff that went to the media blaster.

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[ponchjoe]

AC springs are typically a different part number. If the tears sag it will raise the front. I’ve seen the opposite too, the tears sag so it raises the front

[PurelyGTO68]

Originally Posted by ponchjoe

AC springs are typically a different part number. If the tears sag it will raise the front. I’ve seen the opposite too, the tears sag so it raises the front

Good point.
My car is a convertible non A/C car with power steering and disk brakes...if that matters.

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[ponchjoe]

Originally Posted by ponchjoe

AC springs are typically a different part number. If the tears sag it will raise the front. I’ve seen the opposite too, the tears sag so it raises the front

But there’s no crying (tears) I in the car hobby so I meant rears. Damn spellcheck

[dataway]

Hate to say it, but probably the only solution here is to hope someone with the same car posts and tells you what they used, and how it worked out. Springs are available from so many sources that you are going to have to find someone that got springs that worked well for them.
At least with AMES (our sponsor) you probably have a good chance you can return them if they are way wrong ... but still a lot of work on your end.
I know there are people on this forum that have been through the same thing ... give it some time and they will post here.

[Formulajones]

I only use Coil Spring Specialties out of Kansas. They came highly recommended to me from the Z/28 crowd many years back, and if you know Z/28's and their intended purpose, there are many different front springs used in these cars. This company has been excellent at producing the correct spring with the correct heights for these cars, so I use them for everything these days. A couple of the bigger parts suppliers have now started using Coil Spring Specialties as they have a huge archive of correct springs and spring rates used for all manufactures.

Back in the day I used to buy Moog stuff from the local parts stores. It was always hit and miss. I can't tell you how many sets I've swapped looking for the right height. The problem with these store bought springs these days like Moog for instance, is that most of their numbers have now been superseded and they have combined parts numbers for numerous applications. A way to keep stock down, less production, and save money I guess.

If you call and talk to Coil Spring Specialties, especially about Pontiacs, they will get very in depth on coil springs and how each year is an entirely different spring. We just went through this with my fathers 69GTO and talked about how both 68 and 1970 are different and what Pontiac was trying to accomplish during that time.

With my fathers car, we made a lot of changes, but wanted a stock ride height while at the same time, a spring that reacts and transfers the weight better. Talk about throwing some curve balls at them After telling them aftermarket block, fiberglass hood, aluminum heads, hidden headlights, and the car is street driven as well as wanting weight transfer at the track.
They nailed it. Here's a picture.

If you want to make sure you get exactly what you have, you can also send in your original spring and they can duplicate it exactly. The Z/28 crowd resorted to this with excellent results. Just to give you an idea of the crazy spring specs on these cars, here's a chart with all the springs offered by GM at the time and how options affected the spring rate to give you an idea. See attached chart.
The other alternative I do is use the original springs and do what North suggested and use very small spacers to get the height you want. It's the only way to keep ride quality because if you resort to cutting coils you'll end up with a car that rides like a dump truck, just as Dataway mentioned. It just increases the spring rate to the point the car is uncomfortable.

[dataway]

I assume you have heard the speech about how to tighten the suspension components up AFTER the car has weight on the wheels?

If you tighten the suspension bolts before weight is on the car then the bushings all act as springs and try to hold the car up. This specially applies to the front suspension.

A lot of people have made his error because their suspension was assembled when the car was on blocks, or without an engine, etc.

If that is not your problem ... then might have to send one of those springs back and have them test it for proper rate.