.

 

I have not done this, but need to say right away that it is NOT a 1:1 ratio.

The lever action of the lower control arm, with the pivot at the bushings, gives the springs (attached part-way down the arm) less leverage than the wheel (attached at the end of the arm) has, so a given amount of movement at the spring causes MORE movement at the wheel.
You can determine the ratio by measuring the length of the arm, from the centerline of the bushings to the centerline of the ball joint, and again from the centerline of the bushings to the center of the spring.

Remember to calculate the length of the compressed spring, not the free spring.

- Eric

edit: Here's a diagram -

 

Will you have enough camber adjustment to compensate for the control arms riding higher than normal? You might need the offset UCA shafts...

 

I would start with 2/3 of a coil put it together and drive to see where it settles. You can always go back for more later.

 

i believe summit sells lowering springs pretty cheap. I have been pleased with the summit brands in the past . just thought id throw that out there

 

I was pleased with my Eibachs

 

It will be about a 1:3 ratio, meaning cutting the free length down by 1" will give 2-3" lower ride height. With 68-72 springs, cut the tangential end, leaving the squared off end alone. With 64-66, both ends are tangential and it is usually best to cut a little off each end, leaving an integral number of coils plus 2" more. The 68-72 upper pocket is flat, but the early cars have a formed pocket in the frame and the spring should fit it, ending at the end of the recess, just past a locating hole that yyou can see looking under the upper A arm.

 

X2. Eibach springs are the most consistent springs out there in my opinion. i have no experience with them on cars but they are almost all we used in off road racing.

 

The shorter you make a spring the stiffer it becomes. I cut down coils on a 67 ElCamino years back and was not pleased. Rode like crap and dropped very little (if any) did not measure before.

gearheads78 were your Eibachs progressive?

 

I don't think they were. But not 100% sure on that.

 

Don't cut the springs unless you like feeling every bump and bottoming out. See if dropped spindles are available and keep the ride quality.

 

I wouldn't cut springs

end thread

 

The front springs have been cut on my '63 Starfire and it is way too low, been dropped 4-5"and are going to need replaceing. Does anybody do lowering springs for this car?

 

if you put a lighter engine in the car you need a spring with a lower spring rate[ie smaller wire]

whe we did stock cars we looked for station wagons and air conditioning for heavier springs, we had about a pickup load of spare springs for what we were running and had our own spring rater, but they do not make them tall enough for street cars

if you have a mid size GM frame there are many other springs in the other car lines, the best thing I can say is to get a caliper and look for a smaller wire size

lots of ways to skin a cat take a tall spring and squeeze it down a lot

or take a heavier spring and cut it down some then it will really kick up the rate

best is to find something out of a similar car that has a lighter engine and try it it should go easily doen a inch or 2 which should be tollerable

 

I have cut springs a lot of times. I am using cut 6 cylinder springs in a drag car to get the rate and ride height I want. However, it is hard to get just what you want the first time. (1) You have spring rate, and its increase as the coil gets cut more and more. For example, rear springs can go up in rate quite a bit if you take station wagon springs and cut several inches off them (in a 1964-66 where the top is not a pigtail). I am guessing the rate went from 159 lb/inch to about 200. (2) ride height is sensitive to rate vs. overall length, and may sag a bit after a while depending on quality of the springs, etc. Also, the end coils are wound tighter and it can be hard to predict the effect as you get toward where the coiils are separated from each other more.

 

X2 on what Joe D said.

I've also cut springs many times, using both a cutoff wheel and a torch. The trick when using a torch is to submerge the spring in a bucket of water with the water line just below the cut line. One data point is that on a 1972 Cutlass that originally had a 350 and A/C, I cut one full coil off the stock springs and installed a 455 without A/C. The front end dropped about 2" and the ride quality was fine.

 

Yes, the good way is to use a cut off wheel, protecting the next coil from being scraped or covered with bits of hot metal. Then, debur the ends; even the stock end often is mis-shaped from shearing it off before winding the coil.

 

We have cut springs, heated springs etc.
What I can tell you from doing it to new and old, is that if your springs didnt have 20+ years ware cutting a coil out of a nee spring doesnt hut the ride quality all that bad, a spring as old as yours (if they are stock) no way I would not do it, I would buy a decent spring kit, Eibach or Hotchkiss, better yet drop spindles in front and cut or lowering springs in the back

 

Yes it does, and yes you should buy lowering springs instead.

Talk to the pro-touring crowd on either www.lateral-g.net or www.pro-touring.com
Or you can call Hotchkis and ask the professionals who know suspensions.
Savitske classic and custom wrote a book on suspension info as well.

Both of those vendors spend alot of time answering questions on those sites.
Stock A-body suspension is horrible......literally horrible and lots of room for updating.

 

sorry to dig up an old thread but im looking to lower my 66 here pretty soon and wanted to see if i could find a general rule for cutting coils vs drop the car gets. i have personally lowered my old 62 nova 3" by cutting coils and didnt get a harsh ride but it was bouncy on the freeway but i attributed that to having old shocks. anyways my car has 6 cylinder springs and im looking to cut the front coils for a 2" drop then ill just cut, check repeat on the rear since its easier.

 

I would start with 1/2 coil at a time. I know it will be a pain but if you cut too much at a time you will have to start over.
As you said before be sure to have good shocks.

Gene

 

There is no general rule because the amount of drop varies depending on the control arm length, spring location, spring rate, and car weight. This is entirely trial and error.

I've cut coils on 68-72 cars and gotten about 1"-1.5" drop with about a full coil being cut. Unfortunately, cutting coils causes other problems, as you are putting the suspension arms in a different point on their travel arc than the designers intended when at normal ride height, which can cause problems with getting the right front end alignment. These days I use lowering spindles when available, especially if you are converting drum to disc brakes, as it kills two birds with one stone.

Also, your Nova has the springs above the UPPER control arm, which is completely different from the A-body, so there is zero relationship between the two.

 

Talking about the nova and cutting springs was just to illustrate my experience with cutting coils and having a harsh ride after. I know where the springs are on both cars and the relationship between the two is the fact that cutting coils increases spring rate and many people believe you get a harsh ride because of it.

 

And again, you can't generalize this. Cutting coils increases the spring rate of a given spring (it's true, check the formula). The result is that a cut spring WILL ride harsher. How much is a function of the before and after spring rates and the design of the suspension. Sorry, but your Nova experience means nothing to an A-body. It's like saying that since you got a certain HP increase with a given cam profile on a Ford, you'll get the same on an Olds.

 

I see what your saying, they both increase in spring rate but the increase will vari between the two. But my point still stands that I did not notice an apreciable ride difference after lowering my car 3". I cant imagine the amount I want to lower the olds would give me a harsh ride, I might even like it better since I'm on 6 cylinder springs that I assume are softer than v8 springs. I did find nearly everyone with a 66 chevelle said one full coil got them roughly a 2" drop

 

I put QA1 coil overs in the front of mine.1" spring lowering dropped it a little over two inches. 2 inches in my 68 Cutlass was way to much. Ended up with about 3/4 of an inch.

 

LOL
Will just plop my 2 cents into this thread.
I loved the stance of Black Beauty from the moment I first saw her. But, after getting her home I rolled underneath and discovered a few things. First most noticeable thing was the headers were almost pancaked at the lowest portion of the tubes.
I looked at the left front spring and see the aluminum twist in spacers. Hmmm....
Rolling to the rear I see a steel plate welded between two coils.
Hmmm....
My thoughts are the previous owner down the line wanted to lower the stance so they cut the springs. Then it was TOO low so they used whatever means possible to get the right lift. By doing so they compromised the ride with the compromised spring action. The quickest, easiest and most reliable way to remedy this was to order a set of drop springs. I ordered a set 1" lower than stock. That way I KNOW what I have. I'm not one to be squeamish to get my hands dirty but I'm NOT up to going to the trouble of removing a spring, cutting, reinstalling, testing and removing again till I get it where I want it. That's a job I want to do ONE time only. Another member posted that the best money they spent was for a nice set of coil-overs. Those are adjustable and would solve the issue of guessing or multiple R&R tasks.
But, if you HAVE the time and a lift, go for it.

 

Actually, the most reliable way is dropped spindles. With lowering springs, the amount of drop is still dependent on the weight on the front end (A/C or not, aluminum vs. iron intake, etc). With dropped spindles, the amount of drop is EXACTLY the distance that the wheel centerline is moved up on the spindle. Also, you can swap the spindles without removing the springs, just leave the shocks in place to prevent the springs from coming out. And finally, as I noted above, dropped spindles keep the control arms in the same location as before when at nominal ride height. This way there is no change to the camber curve during suspension travel.

 

I can certainly agree with that Joe. Dropped spindles are a more desirable remedy. BUT, I have to replace butchered springs anyway so the dropped springs was the best and most economical way for me to go. Everything SHOULD align as it is now. May go the dropped spindles IF this doesn't work as I believe it will.

 

I have done all 3, I cut springs on my cars and I used lowering springs and drop spindles. For the A-bodies it seems for every 1/2 coil cut the car dropped bout an 1".
The problem with drop spindles is that you still have to lower the rear and they require a little more work that just swapping the springs.
IMO there is a big difference in the ride quality between the cutting and replacing the springs, especially when driving above 50mph. I am never cutting springs again.
There is couple of options out there, depending on the budget and desired firmness of the ride.
If you can afford it and you like the way the stock ride feels, Eaton springs is the best way to go. They drop the car 1 or 2" but the ride remains soft just like with stock springs, however they will set you back little over $500.
Than there are sport springs, such as Hotchkis, Eibach, BMR etc. They will firm up the ride, improve cornering, improve weight transfer, but they are firm and not as comfortable as stock. IMO this is the way to go. With good quality shocks the firmness of the ride is not as noticeable,
I have BMR 2" drop in the rear and Eibach 1" drop in the front.
Something to be aware of, front dropped almost 3" with Eibach 1" drop spring.
Here it is with the current setup.

 

I have purchased the BMR 1" drop set and new shocks. Can report more after the install. Now, I just have to find the time.