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Old 08-11-2007, 11:13 PM
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Chopping coil springs

I've started on my front end kit and while the springs are out I got the idea to chop them to lower my ride about an inch. I know I know some people don't think its "the correct way" but keep in mind this is a 1959 pontiac. Not a Nova, or a camaro, or a mustang or even a GTO.There are NO aftermarket parts and no drop spindles available. I just want the front end 1" - 1.5" lower. How much would I have to chop the uncompressed spring to lower the car 1.5" when it is fully loaded? The coil is 17.5 inches uncompressed.

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Old 08-12-2007, 01:00 AM
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I'd take 1/2 a coil out at a time and see what happens..

It's hard to tell how many coils to chop, you need to know the springs installed height at ride height, How many coils there are, and then the motion ratio. Usually springs move roughly 1/2 the distance that the spindle does, but without some measuring and ciphering you will find it's just easier to do 1/2 coil at a time, and see if you get where you want to be. Once you cut out a 1/2 coil, you will know about how much each trimming will lower your car.

Hope this helps, mikey
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Old 08-12-2007, 07:01 AM
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Some Pontiacs, that were equipped with A/C from the factory ... had a spacer ring installed between the coil spring and the seat to raise the car ( to compensate for the added weight of A/C ) if your is so equipped ... discard it first ...

I suggest cutting the coil with a cut - off saw ...



Like Powerrodsmike said ... cut a little off ... first ... then continue to remove coils to get it as low as you want.

Deuce ... Moderator
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Old 08-12-2007, 08:13 AM
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DO NOT get the coil hot, or even very warm.
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Old 08-12-2007, 04:49 PM
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Hot Coils = very bad Might even use a sawzall to cut them with might keep it a little cooler.

Shane
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Old 08-12-2007, 05:35 PM
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I always just set them in a chop saw. If you get the end hot it won't matter one bit, the end doesn't affect the spring rate in any measurable amount. You need to heat them to red hot to take the spring temper out anyway.

As far as how hot you can get them, they put springs in an oven and bake them at 400 degrees to powder coat them, I've never heard of them failing after powder coating.

I never tried to cut a spring with a sawzall. Have you?
Spring steel is much harder than drill bits and saw blades.


Just for a laugh, I went and took a brand new lenox sawzall blade, 18 TPI and tried it out on a spring that I just pulled out of the 57 chevy in my shop.

It went in about 1/16" before all the teeth went flat.

Later, mikey
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Old 08-12-2007, 06:02 PM
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Open mouth insert foot ........all I thought about was preserving temper yet not thinking about what that temper would do to the blade........now that I think about it its probabably about the same as the sawmill band saw blades that I use to make knives out of they will wear out a bit or blade before you can hardly get started
Shane
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Old 08-14-2007, 07:39 PM
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Thanks for the tips. The problem with cutting a little at a time is that I do not have the motor in and I'm waiting to do the front end before I drop the motor in. So I'll just cut half of a coil and finish the front end and put the motor in and hope for the best. It will be lower and that is all that matters. I'm not going for a certain exact height but i just want it lower. I'll chop it slowly with a chop saw and let yall know how it goes.
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Old 08-14-2007, 07:43 PM
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Cut through it quickly, otherwise the heat builds up even more in the part, and the little melty bits from the piece you are cutting will clog the cutoff wheel..

I usually push the wheel into the work until I can hear the motor just barely loading down.

Later, mikey
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Old 08-14-2007, 11:26 PM
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cutting coils

I would check with a spring shop as it is my experience that it isn't that expensive to get new springs made. They should be able to calculate the proper height when the make them.
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Old 08-15-2007, 06:22 AM
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Quote:
Originally Posted by Poison Heart
Thanks for the tips. The problem with cutting a little at a time is that I do not have the motor in and I'm waiting to do the front end before I drop the motor in. So I'll just cut half of a coil and finish the front end and put the motor in and hope for the best. It will be lower and that is all that matters. I'm not going for a certain exact height but i just want it lower. I'll chop it slowly with a chop saw and let yall know how it goes.
You can get it right the first time, but it takes a little measuring before you cut.

First, you must determine the suspension linkage ratio. You need a measurement from the inner pivot for the lower arm to the spring centerline on a line which is perpendicular to the axis of the spring. Then, measure, on the shop floor, from a point directly below that inner pivot to the center of the tire patch. Divide the last measurement by the first and you have the suspension linkage ratio.

Next, look at the spring. Does it have a flattened coil at the end? If so, measure its height, multiply by the suspension linkage ratio, and subtract your answer from the desired drop.

The spring has a "pitch" to it, much like a screw. The "active" coils continue to a point, near the end, where the pitch is changing to form the flattened end. The number of active coils is not necessarily a "whole" number. In other words, it might be 7.3 active coils. So, count the active coils. Use a little common sense as to where the "spring" actually ends and the flattened coil begins. Remember, you're going to consider that flattened coil as if it were a spacer and not a spring (see above).

Divide the desired drop (again, less the effect of that flattened coil) by the product of the suspension linkage ratio and the INSTALLED height (of the original spring). You'll have the number of active coils to be removed when you multiply your answer by the total number of coils.

Hope this reaches you in time.

http://home.earthlink.net/~whshope

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Old 08-15-2007, 06:45 AM
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I started to add this as an edit to my post above, but decided to make this a separate post.

Someone is bound to point out that the above can be simplified. And, for all intents and purposes, they're absolutely correct. In fact, if there's no flattened coil, they're correct, PERIOD!

Before it can be expressed in its simplest form, I must define a new term. I'll call it "springdrop." (The name is meaningless, but it's the best I could come up with.) The springdrop is the desired drop divided by the suspension linkage ratio.

Now, the simplified conclusion: The ratio of the springdrop to the installed height (of the original spring) is essentially equal to the ratio of the amount to be cut off (length, NOT coils) to the original free length.

Isn't that a whole lot easier than counting coils?

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Old 08-15-2007, 11:22 AM
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When I use a torch to cut springs, I immerse the spring in a bucket of water to just below where I plan to cut. This prevents any heat damage to the spring temper. I've also used a cutoff saw and that works fine also.
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Old 08-15-2007, 04:16 PM
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Quote:
Originally Posted by Poison Heart
Thanks for the tips. The problem with cutting a little at a time is that I do not have the motor in and I'm waiting to do the front end before I drop the motor in. So I'll just cut half of a coil and finish the front end and put the motor in and hope for the best. It will be lower and that is all that matters. I'm not going for a certain exact height but i just want it lower. I'll chop it slowly with a chop saw and let yall know how it goes.
I would do the springs last.......... after the motor is in and your about to hit the road. If i want it lower just to look at while i am messing with other things I would remove the shock/spring and bolt a tube in. Cut the tube at the desired ride height/ find a way to bolt it in and let it be until i am ready to fit the springs.

I use cut off wheels and keep a wet towel around for when it snags and I cool it off just to pretend it is doing some good.
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Old 08-16-2007, 05:34 AM
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Cuttin' Coils

The first thing I'd like to say is that cutting coils springs is not just a great idea. Yes I know it's been done like a million times by a million people. So has heating springs to lower ride height and if all you care about is a lower ride height and not how your car rides then by all means start chopping. Cutting springs to lower ride height adversely affects ride quality and purpose built lowering springs are not simply shortened stock springs(at least not good lowering springs) they have a different spring rate to compensate for the shorter length. Now I know your car is a bit on the rare side and you don't have the same options available to you that a person building let's say a Chevy Impala might have but I would seriously consider doing an internet search and contact a few spring manufacturers. If money is not an issue you could even have custom springs made but hopefully you can find something through the guidance of their tech department that will work in your car. If you were to go that route though you need to remember if you order 1 1/2 inch lowering springs and install them you car will most likely not drop a full 1 1/2 because your current springs are most likely fatigued from 48 years of holding up that heavy car. They will lower the car 1 1/2 inches from the stock ride height of new stock springs not 1 1/2 from where it is now. Your second option (and in my opinion the best option) is to again contact a few manufacturers like Belltech or DJM to see if any of their lowering spindles will interchange with the spindles on your car. Spindles are the best way to lower cars because they don't change the geometry of the suspension they simply raise the location of the axle in the unit. Then you don't have alignment issues associated with other drop methods. Now most spindles lower the fron either 2 or 2 1/2 inches which is further than you want to go but if you install them along with a fresh set of stock length coils (which are redily available) then you will regain some height by getting rid of your original sagging coils. Now onto option 3 and this is your third best bet. I always recommend this when lowering springs and spindles are either unavailable or money is real tight. Instead of heating or cutting springs cut out the lower spring perch and lower it the amount you want to lower the car (but don't do this if you want to go more than an inch or two) Just mark what will be the two halves of the bucket cut around the outside rim of the spring bucket cut and weld in a strip of heavy gauge sheet metal the height that you want to lower the car and bend it around the opening as you make your tacks. Once you have the strip bent in a complete circle all welded in weld in the piece the you cut out. Just be sure it goes in clocked in the position it was originally in. This method keeps the spring the stock length so ride is not affected and if you finish your welds neatly most people will never realize it's not stock. I know this is a little hard to understand without diagrams but if you want some pictures send me a PM and I can email you some diagrams to make it easier to understand. Or as luck would have it you can just go to the iTunes store and purchase episode 12 of the 2007 season of Musclecar from Spike TV because they just aired an episode where they described this very procedure on a Pontiac Lemans. It works great for mild drops and isn't as difficult as it sounds. Lastly if you do cut your springs I recommend that you still start out with new stock replacement springs simply because your OEM springs are most definitely fatigued and cutting them will make for a harsher ride than necessary. so top pick is drop spindles, next is lowering springs, next modifying the lower spring bucket(free aside from welding supplies and a tiny bit of sheet metal), next buying new springs and cutting, next cutting the original springs and definitely dead last heating them with a torch. I've lowered many cars and trucks and have tried almost everything from adjusting torsion bars, removing leaves from leaf springs, and lowering blocks on leaf springs, torching, cutting, etc. You name it, I've done it and these are my top picks for your ride. That is unless you want to install an adjustable suspension with hydraulics or air springs. Good luck and shoot me a PM if you want some pics of the spring bucket mods.
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