Suspension

[RogerJohnson]

While rebuilding my Berlinetta I bought front and rear suspension springs and Ford Dampers from Don at YKC. Although the ride improved it is still very bouncy and I am thinking of fitting new Spax Dampers, is there any point in buying another set of springs from Spax as well?

Has anyone fitted the front anti roll bar to the Berlinetta, mine has the Cortina front cross member and uprights? Is there any advantage to fitting this roll bar [if one is available]?

If it ever stops raining I might even get near it again. Many thanks Roger

[danny_nelson]

Re: Suspension

Paul Moorhouse always said that this was not reqd on the Berly. Personally I have never felt the need. If you get the wheels upright and very slight toe in the front will be fine for all normal road use.

[lizbillings]

Re: Suspension

What tyre pressure are you running at?

[Dane_Rescueman]

Re: Suspension

Hi Liz, I run without the front roll bar and Moll has very good handling. I use pretty standard off the shelf Cortina dampers but use the front springs from Burton. They are described by them as standard Cortina springs minus two inches. They are about the right stiffness and match the dampers well. I run 20 psi front and 22 psi rear on 205/60 15 tyres.

[Dane_Rescueman]

Re: Suspension

Sorry, forgot to add that I have a 2.1 pinto which is a heavy beast. I can't remember whether yours is a V6 or V8. The former will beheavier and latter a bit lighter. I have adjustabler top wishbones which allow me to set loaded, straight ahead camber at 0° to -0.25°.

[RogerJohnson]

Re: Suspension

HI Liz, I tend to run at 22lb/in2 all round. The car is still bouncy probably because by cutting two inches off the length of a coil springs increases its stiffness therefore making the car bouncy. I have fitted the 1.8 Zetec engine so it might be a tad lighter than the Pinto because I believe it has the same crankcase and a huge aluminium alloy sump. I don't want to lose the car's good roadholding but when the car is bouncing too much this can be reduced by bump steer. I guess it is a compromise and I should drive round potholes, difficult where I live.

[lizbillings]

Re: Suspension

Might be worth trying 20 front and 18 back. that is what I drove my Berli on and ditto the Cabrio. Only really lively one was my first SWB roadster and I had to be very careful especially on a damp road.

[Sportster-Green]

Re: Suspension

...........probably because by cutting two inches off the length of a coil springs increases its stiffness therefore making the car bouncy. .

that isnt the reason...a coil has the same stiffness all over its length...means cutting will not increase the stiffness...(ok, as long as it wont go coil bound..but than you have cut too much anyway)

from wiki:

While shock absorbers serve the purpose of limiting excessive suspension movement, their intended sole purpose is to dampen spring oscillations. Shock absorbers use valving of oil and gasses to absorb excess energy from the springs. Spring rates are chosen by the manufacturer based on the weight of the vehicle, loaded and unloaded. Some people use shocks to modify spring rates but this is not the correct use.

i pressume your springs are too soft....or the dampers are shot.

but as you are saying you bought "ford springs" they should be harder than necessary, as the cortina´s front end weighs more than a marlin.

b4 byuing any further dampers or coils, you may consider to upgrade your front with coil-overs instead of the individual coil and damper used by ford?

lots of TVR Tasmin (which shares also the cortina suspension) owners have converted it successfully. you need to check with google or the specific forums.

the TVR, by the way, has alway used the antirollbar.

[danny_nelson]

Re: Suspension

Coil overs have been used on Berlinettas by some builders/ owners and the subject has been on going since the 1980,s Pilgrim, and Burton sell a (softer) spring. Standard Ford items were available in many different specs which was marked with a colour dot to denote the rate. The front wheels are best upright no neg camber, slight toe in as the donor, Tyre pressure dependant on type , personal preference, etc etc from 18. Cutting two coils off the front springs as the build manual instruction states was to make the top of wheel to wing clearance more pleasing to the eye ( my opinion) I believe the anti roll bar (stabilizer) was not used because of clearance issues, however there is a tie bar. I know of one builder who re fabricated his anti roll bar and fitted it, he may not be on his own, My personal view is that it is not required on a Berly.
Danny.

[dogoncrazy]

Re: Suspension

On a coil spring reducing the number of 'active 'coils WILL increase the spring rate Not lower it!

[dogoncrazy]

Re: Suspension

As a follow up to the above i have calculated the following:
Spring internal diameter of 2.25 inch, .45 inch wire , 12 'active' coils, 12inch free length =570 lbsft/inch with compressed spring rate 6850 approx.
If we take two coils out and in doing so reduce the free length to 10 inch = 685lbsft/in
12 coils at 8 inch free length would give 570lbs but with a force at compressed length of around 4500
But if we reduce the gauge of wire down to .375 of inch and 10 coils at 10 inch free length we get ffigures of 300 lbs/inch and 3000.
These figures are purely calculations and do not take into account whether or not it would be technically possible to have specific numbers of coils within the length quoted, nor does it allow for other steel alloys which would have a different modulus.

[danny_nelson]

Re: Suspension

spot on, I agree, removing coils makes it stiffer.
Danny.

[greyV8pete]

Re: Suspension

that isnt the reason...a coil has the same stiffness all over its length...means cutting will not increase the stiffness....

I don't agree with this. A coil spring is effectively a torsion bar , it's just wound around in the form of a helix. Shortening a straight torsion bar will definitely make it stiffer so cutting turns out of a coil spring (i.e. shortening the total length of the coils) will also make it stiffer. Peter.

[RogerJohnson]

Re: Suspension

Regarding Sports-Green's reply. Cutting the length of a coil springs [and a torsion bar] increases its stiffness [think of it this way - snapping a match stick is easy the first time but becimes harder the shorter it becomes, this may not be a good analogy but an illustration] and the so called SHOCK ABSORBER is often used incorrectly. The shock absorber is the spring because it absorbs bump energy then releases most of it when it rebounds. The gas or hydraulic filled device is a damper because it does not absorb any energy [otherwsie you could support the vehicle weight on it - if you remove the spring the damper will just descend] but it does transfer the bump energy in the form of heat as the gas or oil passes through the valves.

[James]

Re: Suspension

Hi Roger, it sounds as if your dampers are shot!
I agree completely with dogoncrazy, cutting coils off the standard front springs will give you a very harsh ride, almost rock solid on the Berli (good if your racing). I have tried several different set-ups on my Berlinettas and have found the following to be very satisfactory i.e. not too harsh and not too soft. At the rear I have standard (Taunus) Cortina saloon springs and (Monroematic standard Cortina) dampers. At the front I have used (scrapyard) rear springs from from Volvo 740 (two coils cut off) and standard (Monroematic Cortina) dampers. I have no roll bars on my cars (removed both front and rear). It is only on post 1975 Taunus' that there is an anti roll bar on the front. The centre of gravity on the Berlinetta is, compared with the Cortina, very low and and the weight is much lower so the anti roll bars really are superfluous.
Also, if you have worn, or the old type of (not solid) rubber bushes on the rear axle swinging arms you will also get a very "spongy" ride.