spring chart needed

[phat rat]

From the numbers I'm seeing is this for a pair?  Example
              Load rate---2022#
             
            Spring rate---357#  

Well from what I know just worry about the spring rate and the length of the spring.  Those springs are going to compress 1 inch for each 357 lbs.  

So lets say the front of the car is 2000 lbs.  1/2 of that is 1000 lbs. and the spring is going to compress 2.8 inches (1000/357).  So if the spring is 10 inches long compressed it will be 7.2 inches.

See what the compressed height of your current spring is and if you had the frontend weight and took the spring out and measured how long it was you could work backwards and see what it's spring rate is.  Or go by it's current compressed height and using the frontend rate and what I said above you could look for a new spring based on it's length and spring rate.

I'm sure you are remembering that 1/2 inch more at the spring will most likely be more at the tire due to the travel at the spring vs. the tire.  1/2 at the spring might actually raise the car an inch.  Just guessing.

c ya,

Sum

The spring I posted on is as follows.

              Free Ht.----15.94"
            Install Ht.----10.25"

That's a difference of 5.69"  But the way I was understanding what you said the spring would only compress 2.831"

1/2 of 2022# = 1011/357=2.831"

So I'm not understanding. The car weighs 1924# on the frt.  

I just did it with 2022/357 and it comes out 5.663" but that entire weight isn't on just one spring. This is the spring listed for all 73-74 Nova 350/ Ac equipped Novas

[1FATGMC]

Spring Rate - Spring Load - Load Rate

The most mis-understood and the most mis-applied spring terms

What you are about to read is the gospel and anyone who says otherwise is a know-it-all who knows nothing.

(all disagreements can be sent to Mike , 3rd generation spring maker with nearly 30 years experience, all ridiculous arguments will be listened to)

RATE -                   Half the difference between the loads 1-inch above and 1-inch below a specified position.

                                Or put an easier way, it is the amount of weight required to deflect a spring 1-inch.

                                The lower the rate, the softer the spring.

LOAD -                  The amount of weight on the spring.

LOAD RATE -     The amount of weight a spring is designed to be supporting at a certain height.

                                 Load Rate and Rate are not interchangeable terms.

Now let's put what you just learned to use.

A spring which is designed with a free arch of 6-inches and a loaded height of 1.25 inches when

supporting 600 lbs would have a Load Rate of 600 lbs. and a Rate of 126 lbs.

6 inches free height  minus  1.25 inches loaded height = 4.75 inches of deflection

600 lbs.  divided  by  4.75 inches of deflection = 126 lb rate

from...

http://www.eatonsprings.com/rate.htm

--------------------------------

So from that throw away the load rate that you found as it doesn't have anything to do with what you are doing and because of the lever action on the springs your known frontend weight isn't going to help much.  Just work with the spring rate.

The problem with all of this figuring is that 1/2 inch more spring height doesn't transfer into 1/2 inch more car height.  The location of the spring on the A-arm gets levers into the equation and makes it a lot harder to figure without more math and knowing the length of those levers..

Probably the best I could come up with is raise the car with a jack to the height you want.  Now measure the new spring length.  This is how long you now want the new spring to be compressed in it's compressed state with the weight on it.

Forget the frontend weight and figure the weight your old spring actually saw by knowing it's compressed length, before you jacked the car up, and it's free length, the length it would be if it was out of the car.  Now find a new spring that will give you the length you want using the weight the spring is actually seeing using the rate and length of the new spring like we talked about further up the thread.

Simple enough   . PM me if you want me to call.

If it doesn't work and you might want to do this in the first place call one of the aftermarket people that make camaro/nova suspension stuff and tell them what you are trying to do and I'll bet they could sell you a spring that would get you close.

c ya and aren't you glad it's spring,

Sum

[enjenjo]

You sure the load rate isn't listed as "per pair"?

[phat rat]

You sure the load rate isn't listed as "per pair"?

Frank the chart is here. It doesn't say per pair but it would sure seem as though it is.

http://bbb-carb.com/moog_Coil_Springs.htm

Then I went to here for the Nova listings.

http://bbb-carb.com/coilsprings/chevy/nova_rwd.htm

When I was on the Chevy Talk forumn that George suggested I found guys who said "that spring lowered my car an inch"  Next guy comes in and says " that same spring raised my car 2 inches" Thus the quandry. That's also where I found reference to coil overs made for Novas.

Thanks Sum, I'm going to go and check out Eatons site

Would I be thinking correctly that the Install height is the height of the spring with the car on the ground and ready to drive?

[1FATGMC]

.................Would I be thinking correctly that the Install height is the height of the spring with the car on the ground and ready to drive?

I would think so, that is the way installed spring height is referred to for the valve springs in your head.  The difference is that they are not free, but captured at a height depending on valve stem length, retainers, spring pocket, shims, etc..

But like the guys with the novas it is going to depend all on the front end weight that the spring sees.  How much are you trying to raise it anyway??

Keep in mind the spacers.  When if was ok but the spring wasn't in the pocket right it was probably only one coil thickness higher and a 1/2 to 5/8 spacer might get you right back where you were.  I think I have a rubber one on one side and a steel one on the other as I wasn't trying to raise both sides the same.  The builder, won't mention names, probably put the body on crooked  :cry: ,

Sum

[phat rat]

Well I was under it this afternoon and the right side is setting on the bumper and the left side is a 1/2" higher. So it's going to need raising up better than an inch. It dropped at least this much when the springs were positioned right. Plus it really needed to be raised up a bit even before that. So either new springs or coil overs.

[enjenjo]

Ok, free height does not have much relationship with installed height, and none with spring rate. Installed height depends on being installed in the original application.

So if the installed height on a Nova is 10.25", a six cylinder spring would be different that a V8 spring, and that would be different than a Big block spring, although properly applied, they would all be the same height under load.

So, if you want to raise the car, you need a spring with a higher rate, and a similar installed length. The best way to do this, is to measure the diameter of the spring wire, and get one that is slightly thicker. For an inch, .020 thicker wire should be enough.

[Dave]

Well I was under it this afternoon and the right side is setting on the bumper and the left side is a 1/2" higher. So it's going to need raising up better than an inch. It dropped at least this much when the springs were positioned right. Plus it really needed to be raised up a bit even before that. So either new springs or coil overs.

Well if it was me id go with the coil overs Jack.. the only problem with em is getting the right spring rate. The nice part is adjustable ride height..  Thats real interesting all the miles you put on it and the coils were fine although they were not set in the pockets right ..  :?:  :?:  :?:
Good luck......
Dave

[phat rat]

Well I was under it this afternoon and the right side is setting on the bumper and the left side is a 1/2" higher. So it's going to need raising up better than an inch. It dropped at least this much when the springs were positioned right. Plus it really needed to be raised up a bit even before that. So either new springs or coil overs.

Well if it was me id go with the coil overs Jack.. the only problem with em is getting the right spring rate. The nice part is adjustable ride height..  Thats real interesting all the miles you put on it and the coils were fine although they were not set in the pockets right ..  :?:  :?:  :?:
Good luck......
Dave

Dave, I can't figure that out either. But what other scenario is there? The a-arm bushings were replaced, nothing else was done. I noticed it as soon as I drove up and saw the car sitting there. That's how noticable it is. The adjustable ride height and not having to install and take out who knows how many times for regular springs sure makes a case for the coil overs. Plus they wouldn't settle after a year or two which happened when the car was first put together.

Frank, wire size is .609, .625 and .640. The .640 is what I have and these are for 350 and 454.  Install height is 10.25 or 10.75, free height is from 14.98 to 16.06. The ones with install of 10.25 have a free height of 15.94

[Bugpac]

Ok, free height does not have much relationship with installed height, and none with spring rate. Installed height depends on being installed in the original application.

So if the installed height on a Nova is 10.25", a six cylinder spring would be different that a V8 spring, and that would be different than a Big block spring, although properly applied, they would all be the same height under load.

So, if you want to raise the car, you need a spring with a higher rate, and a similar installed length. The best way to do this, is to measure the diameter of the spring wire, and get one that is slightly thicker. For an inch, .020 thicker wire should be enough.

Sorry frank, i have to disagree, raising spring rate will only make the car a rougher ride, or be capable of more load, and ride higher, The installed height of the spring has everything to do with it IMO....  Maybe I am wrong and maybe i will learn something new....Please educate me if so...But IMO the weight of the car has everything to do with the sag of the spring....the same wire size of spring is going to compress exactly the same length, rather it be 10" long or 20" long, with the same exact weight and leverage ratio.So why wouldn't you just want to search out the spring that is longer? Now if the springs were overloaded from the beginning, I can see needing to up the coil diameter...

With my off road cars, Spring rates are crucial. Most of the time ride height is adjustable..

[1FATGMC]

Sorry frank, i have to disagree, raising spring rate will only make the car a rougher ride, or be capable of more load, and ride higher, The installed height of the spring has everything to do with it IMO....  Maybe I am wrong and maybe i will learn something new....Please educate me if so...But IMO the weight of the car has everything to do with the sag of the spring....the same wire size of spring is going to compress exactly the same length, rather it be 10" long or 20" long, with the same exact weight and leverage ratio.So why wouldn't you just want to search out the spring that is longer? .........

I agree with all of that.  The leafs I put in the back of my truck had a higher spring rate and did raise the back as they didn't compress as much and they did make for a stiffer ride.  If it would have been a lot stiffer then you could call it "rougher", so if the ride now is on the verge of being too stiff/rough then I would search out a longer spring with the same rate.

I don't think coil-overs are necessarily the magic bullet either.  You are still going to have to figure out a spring rate that will work.  They usually don't have the travel and thus have to be stiffer and that can translate into rougher.  Also there is only so much height adjustment you can makeup with them.  You can fine tune the ride height, but not over a large range from what I've seen.

I'll still stick to the idea that 5/8 inch spacers would get the 1 inch back.  They wouldn't cost much to try out.  That's my story and I'm sticking to it  

Sum

[enjenjo]

Ok, free height does not have much relationship with installed height, and none with spring rate. Installed height depends on being installed in the original application.

So if the installed height on a Nova is 10.25", a six cylinder spring would be different that a V8 spring, and that would be different than a Big block spring, although properly applied, they would all be the same height under load.

So, if you want to raise the car, you need a spring with a higher rate, and a similar installed length. The best way to do this, is to measure the diameter of the spring wire, and get one that is slightly thicker. For an inch, .020 thicker wire should be enough.

Sorry frank, i have to disagree, raising spring rate will only make the car a rougher ride, or be capable of more load, and ride higher, The installed height of the spring has everything to do with it IMO....  Maybe I am wrong and maybe i will learn something new....Please educate me if so...But IMO the weight of the car has everything to do with the sag of the spring....the same wire size of spring is going to compress exactly the same length, rather it be 10" long or 20" long, with the same exact weight and leverage ratio.So why wouldn't you just want to search out the spring that is longer? Now if the springs were overloaded from the beginning, I can see needing to up the coil diameter...

With my off road cars, Spring rates are crucial. Most of the time ride height is adjustable..

The installed height is only valid if you are carrying the design weight. If you carry more weight, the installed height will be less, if less weight, the installed height will be more. If the design installed height with 2200 lbs is 10.25", it  will be 10.50" high with 2000 lbs, and 10" high  with 2400 lbs. All these figures are approximations.

Unless the spring is worn out, which is possible considering the miles that Jack drives, then he needs more spring rate to get it off the bumpers. If he is happy with the ride, the best thing to do would be to install a spring spacer to raise it. They are available at most 4x4 shops.

A coil spring works by twisting the wire, it actually works more like a torsion bar, rather than bending like a leaf spring. The thicker the wire, the more resistance to twisting there is. The longer the wire, the less resistance to twisting there is.

If you look at the springs on older cars, late 40s and early 50s, you will see that they used about 15 turns  of wire, much  thicker than is used today. Current cars use about 5 turns of much thinner wire. Yet the spring rates are similar, because the longer wire in the old springs, will twist more because of the length, for the same applied weight.

So lets carry this to ridiculous lengths. Suppose we wind a spring with 2" wire. The spring rate would be about 20,000 lbs per inch. To have a 10.25" installed height, the spring would be about 10.6" free height. now we wind another spring with .25 wire, with a spring rate of about 50 lbs. For a 10.25" installed height the spring would  have to be over 30" free height.

Now, since Jack says the front end is setting on the suspension bumpers, we have two possible reasons. 1, the spring is worn out, or 2, the spring rate is too low for the weight carried. The third possibility, too short a spring, does not apply because he didn't change the spring length this time around.

[Bugpac]

Ok i agree, I thought he said it was fine, but could have been 1" taller...I was basing my conclusion that he wanted to raise the car 1" higher than it originally sat...

[phat rat]

Wow, I didn't think would get this long. When the car was built we cut one turn off the (6cyl I think) springs. This gave the ride height I wanted although after about a year it settled about an inch. I was content with this for a while. But a few years ago I took it apart and added a spacer, after driving it a short time I took them out as the car was riding level which I didn't care for. I wanted it to be nose down. Forward to last week. I was under the car doing my annual clean up and inspection and found that two of the a-arm bushings were bad. I didn't want to change them as I remember what a heck of a job it was the first time.  So I took it to a fellow who I trust to do work that I won't/can't do. When I picked it up I realized right away the car sat lower. When I talked with him about it he told me that he had had a real bear of a time getting one of them to seat in the correct spot, ie: the end of the spring where it's supposed to be in the pocket, in fact he had to do one twice. So all I can think is that it was not in there correctly when I took it to him. Otherwise what could change the height of the car by simply changing out the bushings?
I'm not totally hooked on coilovers yet. I can't find a lot of info, such as loaded height and such. What I've seen so far I'm not sure I could get it down as low as I want it. I read about it for Novas over on a Nova board.

[Bugpac]

Wow, I didn't think would get this long. When the car was built we cut one turn off the (6cyl I think) springs. This gave the ride height I wanted although after about a year it settled about an inch. I was content with this for a while. But a few years ago I took it apart and added a spacer, after driving it a short time I took them out as the car was riding level which I didn't care for. I wanted it to be nose down. Forward to last week. I was under the car doing my annual clean up and inspection and found that two of the a-arm bushings were bad. I didn't want to change them as I remember what a heck of a job it was the first time.  So I took it to a fellow who I trust to do work that I won't/can't do. When I picked it up I realized right away the car sat lower. When I talked with him about it he told me that he had had a real bear of a time getting one of them to seat in the correct spot, ie: the end of the spring where it's supposed to be in the pocket, in fact he had to do one twice. So all I can think is that it was not in there correctly when I took it to him. Otherwise what could change the height of the car by simply changing out the bushings?
I'm not totally hooked on coilovers yet. I can't find a lot of info, such as loaded height and such. What I've seen so far I'm not sure I could get it down as low as I want it. I read about it for Novas over on a Nova board.

so maybe reinstall the stockers you used before, then in a yr it will be perfect...

If your going to run coilovers, do the math the first time, that link i posted is an excellent link to figure out all the details, coil over springs are about 50.00 each every time you change them....