After searching this forum for "cut front coils" I've noticed a few things. One is that there is no agreement or consistency on whether the cut the top or bottom coils, in fact when people have talked about cutting their coils they rarely refer to which end they cut. What I've taken away from reading endless posts on this is that the reason for the inconsistent results is that no one does it the same way as anyone else. The one thing that I've figured out from all this is to take it half a coil at a time until achieving the desired result, although which end to take half a coil from is anybody's guess. In my car with an LS1 it definitely needs done because of the 130 or so pounds that is no longer there.

 

What size is your wheel/tire combination? Are the springs still on the car? The only way you will know if you have stock springs is to remove one. It's not rocket science, it's your choice which end you choose to cut. Stock springs are longer than aftermarket springs. If you don't feel comfortable cutting them, you can buy 550 springs from any of the Corvette vendors. Most who buy them are satisfied with the ride height and handling.

 

Since I am a rookie....don't take my findings as facts. Use them to try and make some sense of the process. (I have been known to get my facts confused....LOL) The front end of my '68 sits 29" from the ground to the lip of the front fender---much too high. I removed one "coil" from the "tightly wound" end of the spring which reduced the fender height 3/4".......I will remove another coil tomorrow from the same end, and also 2 coils from the other spring to see how the car will sit with both front springs the same length....(removing another coil could likely cause a much larger drop in the height of the fender than the 3/4" it dropped after the first coil was removed....this is where things get dicey!! I hope this info helps you....maybe we can both post here to provide some info that will make more sense to others.

Below is a "before" pic of the fender height.......





The first coil was cut from the tightly wound end....after re-installing the spring (without shocks on the car).....the car had the same amount of "bounce" as before the cut.....I cut 1 full "wrap" so the spring would re-install into the upper and lower spring pockets correctly......(notice that the other loosely-wound end of the spring is shaped to sit "flatly in the frame pocket---If I were to cut from that end, I would have to 're-bend" the end of the coil to be "flat")





I will post more pics tomorrow of the new changes.

 

By cutting the coil from the tightly wrapped end of the spring, you have not affected the spring rate or ride height as much as if you had cut from the other end. The stock springs are variable rate, to offer a soft ride but good handling.. The closely wound coils are designed to stack tightly on the one end, and offer a soft rate at regular ride height. As the spring compresses further, the more widely spaced coils begin to compress, and exhibit a higher rate, thereby increasing the roll stiffness at that point of wheel travel.

 

This is some good info, I didn't know that they were variable rate and that was the reason for the unevenly spaced coils, this makes it pretty important which end you cut. I know there's a hole in the lower control arm that the tip of the spring goes into, it sounds like there's another one in the upper spring pocket? Or is it a depression that matches the shape of the spring? In either case it seems that you're limited to cutting in one coil sections for proper fit, which affects the decision of which end to cut based on how much you want it to drop. I've read that you can expect a 2 inch drop if you cut one coil from the widely spaced end. Mine sets at 29 inches from the floor to the lip, (it's actually 28 5/8 but it has a 235/60 15 which is the wrong size tire and I'm going to put the correct size on which will bring up to about 29 inches) so I'd like at least an inch drop if not an inch and a half. If I'm limited to cutting in one coil increments then it would seem I can only cut from the top of the spring, which I actually like since the ride would be relative unchanged. Doorgunner, if you got a 3/4 inch drop by cutting a coil from the top of the spring, are you expecting a further drop after driving the car as some have suggested?

 

mine sat at over 29" after i added aluminum heads etc. i just put the VBP 550 lb springs and cut 3/4 of a coil , it dropped that front end exactly where i wanted it. definitely a lowered look. if you don't want it that low maybe a 1/4 coil would do you well.

 

Here's one approach I've taken... Look at the spacing between the coils with the suspension fully settled at both the top and bottom. Since the load on the spring will remain the same, one would expect that the height of the control arm drop would be the distance between the cut coil; however, since the wheel is roughly twice the distance from the control arm pivot as the center of the spring, the drop height will be roughly twice the distance of the loaded cut coil.

Since the spring pockets are indented for the end of the spring to keep it from moving in the pocket, I don't recommend fractions of a coil.

 

I used the "cool and cut" spring-end bending method to lower my '34 street truck" 3 inches, which weighs 3950 lbs and has a 350 cu.in/A.C./M. steering/M. brakes/No Smog....

Reference: The front suspension sat 4-5" high also, before cutting off the coil springs to lower it 3".....




The shocks are what make the final adjustment on the ride quality...cheap shocks=rough ride...since I wanted a "smooth ride" and was not concerned about sport-driving much, I intalled Monroe SensaTrac shocks, causing the truck to ride similar to a car. I can see how SPORT shocks would cause a much firmer ride even with "slightly soft" coil springs. But, those who prefer better handling whic a Vette was designed for, the shocks recommended the most on this forum by expert members should be considered (I needed to "adjust" my vehicles to a smoother ride because of damaged discs in my spine).

It's time for me to go to the garage/cut one more coil off the driver's side spring......I think I'll cut from the larger spaced end to get a larger drop, and will not "rebend" the end of the coil spring .....I'll do the passenger's side spring the same way that I am cutting the driver's-side spring.....then post pics after I drive the car a couple miles over some bumps to make sure the suspension is settled (of course I'll re-align the front suspension myself, then bring the car to an alignment shop to have the alignment "finished correctly".

 

I cut the same amount of tight coil as Doorgunner:

 

the best rule of thumb for how much to cut off a coil spring came for a guy who made springs for over 60 years. he told me measure the height at the top of the wheel well, decide how much drop you want , remove the spring and measure it, mark the spring with the amount you want dropped and cut it. in other words shorten the springs overall length the amount of drop you want. But, variable rate springs should be cut on the widely spaced end. he also said that if you need more than 2 1/2 inches a new spring would probably be better.

 

Good info!

 

going by that my car should have dropped almost 12''

 

I made the second cut on the driver's side coil spring......took the car thru the neighborhood over some nice bumps...

The fender to tire clearance is about 3/4" higher than I am aiming for....

BUT LET'S REMEMBER THAT i STILL HAVE TO REMOVE/CUT/RE-INSTALL THE PASSENGER'S SIDE COIL SPRING..............WHICH WILL CAUSE THE DRIVER'S SIDE OF THE CAR TO SETTLE MORE.

I'll post pics with more details in about an hour.


NOTE: This time the whole process was less than one hour from start.....to test drive....to measuring the fender after the suspension settled.

 

My car was at 29" floor-to-fender lip....I cut 2 wraps off the "open end" of the coil spring.......now the driver's side of the car is very close to what I want in clearance above the tire (still need to modify the other--passenger's spring)

That's probably why the unofficial rule is to "Cut a little off at a time"....so we don't end up ruining a good coil spring.

( The camber and toe "went bizerk" on the passenger's wheel....needs LOTS of adjustment....LOL)

 

O.K.

I'm a Rookie......bear with me....

USE JACKSTANDS/BE CAREFUL/SPRINGS BITE!

I found from forum members that leaving the wheel on the car makes it easier (which doesn't sound right...LOL)........ I jacked the car....jackstand under frame......jacked lower control arm.....removed the shock......removed nut & loosened tierod with pickle fork......lowered control arm....pulled wheel away a feel inches.....loosened end caps on lower control arm shaft to allow control arm to settle to floor....pried spring out of lower arm and removed from chassis...






Here is a pick looking up into the spring pocket....notice to the left/inside edge of the top coil.....is a 3/8" hole I drilled with a 1& 1/4" long bolt inserted into the hole to hold the top of the spring in the pocket when re-installing the spring......this bolt keeps the upper spring from binding/refusing to stay in the spring pocket depression...






The spring is removed with a prybar ( FIRST...remove the rubber bump-stop to keep from damaging it)......Here is a pic of the " upper spring alignment bolt that I installed....






Here's a pic of the 1st and 2nd cut and changes that the cuts made/the measurements aren't exact...






Here's a measurement after the spring is re-in stalled and the car is driven to settle the suspension.....





I'll post more pics after I remove the passenger's spring and modify it (I hope all of the above makes some sense, since I did not do a step-by-step explanation--assuming that members have read threads about the topic).

 

wow, that's still really high. my ground to fender measurement is about 26.5'', with a 26'' tire

looks like you have some really short tires there too, what size are they?

 

I am going to change my 15" original wheels for some 18" alloys and i want to lower the car also.

The discussion about cutting springs always interested me because there are so many different opinions about a simple mechanical device as a coil spring.

The way i look at it: (*)

A coil spring is nothing more than a coiled torsion bar, just like the ones you have in your front and rear suspension, and it functions under the same principles.

The stiffness (stiffness: how much deflection under a certain load) of a torsion bar is only set by thickness and length. Think of a torsion bar with one end rigid and a torque load on the other end and it is not so hard to figure out that a thinner and longer torsion bar will turn more under the same load than a shorter and thicker one.

Back to the coil spring, this is just the same torsion bar but coiled into a spiral. Spring geometry/stiffness is stated as the result of wire thickness, number of coils and coil diameter. The last two are just another way of designating bar length.

So a spring which more coils is softer than the same spring with lesser coils, and a spring with a bigger coil diameter is softer than the same spring with a smaller diameter, simple mechanics.

Cutting one coil of the spring will reduce its number of working coils so the spring becomes stiffer.

A modern rising rate spring has a progressively wound coil, our Vettes have dual rate springs (looking at the picture above) meaning one half of the spring the coils are wound tighter than the other end. The tight coil end is softer than the end which the coils are more spaced. Normally the "soft" end handles minor bumps smoothening the ride out as mentioned above but under heavy compression the soft tight coils all stack up so they do not contribute to the spring anymore so the number of operating coils is reduced, firming up the spring!

So it does make a huge difference if you cut one end or the other.

And about the ride height: If you cut one inch off, the spring becomes one inch shorter and a bit stiffer. But the spring is not positioned at your wheel, but much more inside. I don't know the exact ratio but if your spring is roughly positioned in the middle between the wheel and the lower control arm connection point, any 1" cut will allow the wheel, which has twice the distance, to travel 2".







(*) meaning: my personal opinion.

 

Wow, had your doors blown off, eh?! You need to focus on engine power and not the springs.

 

That's a good one!

 

So you cut one coil?