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Customs Cutting coil springs

Discussion in 'The Hokey Ass Message Board' started by zipoleon, Feb 20, 2018.

  1. I just bought a '49 Chevy and it sits too high in the front for my liking. I will probably lower it with 2" dropped uprights, but I don't think that will be enough. Could anybody tell me what approx. a cut of the coil springs, about 1/2 a coil will lower it, 1 coil ?
  2. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,306

    from Quincy, IL

    About 1 1/2 times the amount removed, maybe a little bit more than that, has been my experience. The shorter coil will also be a bit stiffer.

  3. LostBoy
    Joined: Mar 16, 2016
    Posts: 217


    I cut the coils on my corvair and the only problem I ran into was the springs we're original and so one sags more than the other even though I cut then evenly. Eventually I'll buy new ones and cut them.

    Sent from my LG-H931 using Tapatalk
  4. 29moonshine
    Joined: Dec 30, 2006
    Posts: 1,329


    depending on the coil rate and the weight of the car. i have cut 1/2 coil and it dropped the car 1" then the next time i cut a 1/2 coil it dropped that car 2"

  5. squirrel
    Joined: Sep 23, 2004
    Posts: 50,910


    In other words, sneak up on it, don't cut a bunch at the first try. Also drive it around for a while at it's new height before deciding it needs to go lower....
    40two and pat59 like this.
  6. verde742
    Joined: Aug 11, 2010
    Posts: 5,789


    if it sags just heat a little way from where it sets in the "pocket"

    put something under it to stop it from too much sag when heating, or you'll be going back to other side.. let cool, don't cool it. (not even with oil, just let it cool)
  7. A good "rule of thumb" is to cut half the amount you want to lower the car from the free standing height of the spring. (If you want to lower the car 2 inches cut 1 inch from the height of the springs unloaded height.)

    This is not an exact science though, so as already mentioned, maybe sneak up on the amount you cut. You can always make it shorter later, but it's pretty tough to make it longer again.
    scrapiron likes this.
  8. BJR
    Joined: Mar 11, 2005
    Posts: 7,462


    Put blocks on the ground under the frame at the height you want the frame to end up at. Then heat the spring until it just sits on the blocks. As said go slow.
    Last edited: Feb 20, 2018
  9. Gman0046
    Joined: Jul 24, 2005
    Posts: 6,259


    The Eaton spring company has a great tutorial on their website for cutting coils.
  10. Thanks everyone, I watched the Eaton Spring tutorial and learned a lot. I'm going to talk to them.
  11. 302GMC
    Joined: Dec 15, 2005
    Posts: 7,152

    from Idaho

    Basic Idaho rule on pre-'54 Chevrolets ... 2 coils & saw the rubber stops halfway off ...
    e z i likes this.
  13. About how much will this lower the front. If it works in Idaho, will it work in Ohio or do I have to allow for windage?
    partsdawg likes this.
  14. My 50 with one loop cut off original springs. With small block engine, the front never bottomed out. Next one I did was a 40 chevy and I used an shop-made mustang II style suspension. A 100% improvement. RockysDelivery.jpg
  15. 302GMC
    Joined: Dec 15, 2005
    Posts: 7,152

    from Idaho

    With 6.50 x 14'' front tires, it was good for 6'' ... we didn't drop the rear - the rake was still in vogue. We were also 14-15 years old, driving $35 Chevrolets ...
    The '40s-'50s beaters were the teenage boy's video games of the day, you might say. If you weren't into cars, you were an oddball ...
    Hollywood-East and e z i like this.
  16. lostone
    Joined: Oct 13, 2013
    Posts: 1,999

    from kansas

    depending on how far you want to drop it I would go with heating the springs, pull the shocks and have a friend help. heat gently just past the spring pocket and when you just see movement of the spring stop, have your friend bounce the front of the car, then go to the other side and do the same thing, alittle at a time. work yourself back and forth this way and you can put it exactly where you want it. My old boss could do it and put them with in a 1/4" of the desired height the customer wanted. of course he had been doing it since the 40's
  17. If the spring is too tall, cut it.
    But if it rides too high why not fix that problem instead of introducing another problem with a spring that's too short.
  18. verde742
    Joined: Aug 11, 2010
    Posts: 5,789


    before you start: measure vertically from top center of wheel opening down to bottom of wheel edge. see if the are the same to start,? Make sure they measure the same at the finish.
  19. CME1
    Joined: Aug 10, 2010
    Posts: 231


    I have always pulled the springs out. And as verde742 says, measure the springs before you cut. After sitting for years and bouncing around on the rough roads we have here, the springs will settle. And most times they do not settle evenly. I have found that cutting one coil will lower one inch.
  20. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,283


    Measure the motion ratio [ a tape measure is near enough ]
    Most GM cars are 2/3 [so if you cut 2/3" it will drop 1" or cut 1" will drop 1-1/2"]

    A shorter spring will be slightly stiffer [ divided by the number of active coils ]

    1 motion ratio.gif
    31Vicky with a hemi likes this.
  21. Thanks everyone, all good suggestions, appreciate the help.
  22. Hot Rods Ta Hell
    Joined: Apr 20, 2008
    Posts: 4,430

    Hot Rods Ta Hell

    For the sake of a bit over $100, Do it the right way and order a set of 2"-3" lowering springs designed for your car. You're going to R&R the present springs anyway to cut them when you have it blown apart to swap in dropped uprights (and I assume rebuild the front end if it needs it).
    If they're original springs they're damn near 70 years old.

    Don't be lazy and take a torch to them-it'll screw up the temper.

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