I cut my New front springs, what do you think?

[Buffalobillpatrick]

Car is 72 Monte, still up on blocks.

355 SB, Aluminum heads, radiator, removed A/C, battery in trunk.
Bilstein shocks, all new steering components & brakes with SSBC disc in front.

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

My new BB springs. Moog 5536 15" free length & 487#/in. rate. The front end would have been WAY TOO HIGH.

They had a change in angle at the bottom to a flatter shape where they sit on lower A-arm.

I was going to cut off 1 full coil which would have given me only about 1" reduction in free length & dropped car about 2" from WAY TOO HIGH, down to way high.

So I cut off 1.5 coils which gave me a free length of 13.5"

This should make the spring rate about 593# / in. with an installed height of 10.4" (maybe) Pretty stiff for street?

Stock SB springs (Moog 6330) show an installed height of 11.25"

11.25 - 10.4 (maybe) = .85, .85 x 2 = 1.7" car front lower than stock (MAYBE)

Installed height 10.4" (maybe) - 9" (to bump stop) = 1.4" x 593# = 830# before I hit lower bump stop, I think this would be a very big bump?

Should I grind a flat area on the bottom of springs where they sit on the lower A-arm?

BBP

[David Pozzi]

Often a car bottoms the headers before it hits the bump stops.
I may be wrong but it's very easy to come out lower than expected, and I think you will be. If you are putting the cut end of the coil on the lower A arm it wouldn't hurt to round it off there. Once the weight is on it, the end angle won't be so bad to the arm.



I used a 13.5" 700 lb coil on a first gen Camaro and it was VERY low and that was with a small block, but your geometry is different than a Camaro.
David

[Buffalobillpatrick]

Do I have the ends mixed up?

I thought that the flatter tapered end went up around the bump in the frame to keep it centered?

The end that I cut was only bent at an angle for a couple inches.

BBP

[Buffalobillpatrick]

Moog shows an installed height of 11" for these springs in BB with all accessories. Mine would have set HIGHER.

I'm pretty sure on this formula as I used it came within .3% of what Moog has in their table.

CORRECT formula
STIFFNESS OF COIL SPRING
K = W x W x W x W x G / N x D x D x D

K-Spring rate (Ib/in) I calculated 488.6 (moog 5536 says 487) .3% difference
W-Diameter of
spring wire (in.) .687
G-1,500,000
N-Number of
"free" coils + 0.5, 8 + .5 (after cut 7)
D- Diameter of
spring coil (in.) 4.317
center to center

Front shocks are Bilstein BE3-D150-HO

BBP

[JRouche]

Often a car bottoms the headers before it hits the bump stops.

And your not kidding. My header flanges are the lowest portion of my car in between the rear and front suspension. And what kills me on my headers is they welded the flange so one of the corners is pointing straight down on both headers. Whats up with that? Why not clock it over a lil so two of the flange corners are at five and seven O'clock. It would give almost an inch more clearance. Something simple. JR

[David Pozzi]

Buffalobillpatrick
You might be fine, I guess I'm a pessimist.

JRouche,
yes, a lot more attention needs to be paid by the header mfr's.

[Buffalobillpatrick]

I found it tricky to count the coils.

I counted 10 complete coils but 8 gives the correct answer +.5

8.5 gives 488#/in.

So it looks like you don't count the 1st coil on each end.

Here is another source of info:

http://www.hotchkis.net/_uploaded_fi...257188file.pdf

"- The spring/A-arm motion ratio is approximately 2:1, so for every 1 inch of Free-Length you cut off the spring
the car will lower 2”. This is only an approximation."

If you have your car on a flat level surface, I think you should measure your current height & decide how much you want to drop it. Then cut 1/2 that off the free length of your springs on the bottom ends.

BBP

[CarlC]

A wise man once told me:

"If you're not a pessimist, you have not been around long enough."

;-)

[David Pozzi]

;-)
I used to wonder why my dad was that way, - now I understand...

The cut coil won't properly sit in the spring pocket, so that will throw off any estimates. Even wheel offsets will have an effect. You are also assuming the stock coil is too high and how much it's too high. All Moog coils are 5% stiffer than stock by the way. It' might be OK, you gotta start somewhere. My experience with Camaro coils is the first coil does not do much, the second coil does a LOT.
David

[Buffalobillpatrick]

David, These are BB springs in a lightened SB front end, I don't think it's an assumption that they would have been too high. I wanted a more performance lower stance.

This cutting the spring 1.5 coils is just a calibrated guess.

I ground the ends where they sit on the LCA's about 1/3 of the spring diameter, in a tapered flattened manner, so as to spread the pressure away from the sharp end.

It will also be lowered another 1/2" due to the SC&C Stage 2 UCA's & tall Howe BJ's

BBP

[gearheads78]

I would cut about 1/2 of what you will think it needs put it together and drive it around the block. I would rather time mine apart twice than ruin a set of springs because I went too much first cut.

Besides does'nt a 70-72 Monte hood weigh as must as a BBC

[protour_chevelle]

My experience with Camaro coils is the first coil does not do much, the second coil does a LOT.
David

Story of my life, with a couple changes in your wording. haha

[paul67]

I found the best way was to put the springs in sit the car on flat ground put a block of timber under the crossmember the height you want + 1" for settlement,heat the springs up lower coil sheilding the springs from draft and wind , when car settles wrap spring in a fire proof blanket or keep heat on to slowly cool springs till warm and there you have you ride height. Or cut coils 1/4 at a time till ride height,the more you cut the easyer the spring goes back in but remember you cannot put the cut piece back on.

[gearheads78]

I found the best way was to put the springs in sit the car on flat ground put a block of timber under the crossmember the height you want + 1" for settlement,heat the springs up lower coil sheilding the springs from draft and wind , when car settles wrap spring in a fire proof blanket or keep heat on to slowly cool springs till warm and there you have you ride height. Or cut coils 1/4 at a time till ride height,the more you cut the easyer the spring goes back in but remember you cannot put the cut piece back on.

I would never heat the springs. I inconstantly destroys the temper in the spring