Re-using Old Road Springs

[berni29]

Hi

I will be lifting the body off my plus 2 soon, ready to go onto a new chassis. I have the old springs from that car plus springs from three other plus 2s. In fact 2 sets from plus2's and 2 from the later "s". They all seem OK.

Were the spring rates changed during the life of the car? I am wondering if new ones really are worthwhile. I see some cars that seem to sit really high up and I guess that those ones have had the springs replaced. Maybe not though. I am not sure if they deteriorate over time. The ones on my brothers 1986 Jag certainly have. The rear on that car sits very low. The plus 2 ones are 36 years old now.

I do not want to have the car sit tooooo low because I remember that my old one used to ground out on speed humps sometimes, and there are loads of them in by area. There again it is not a 4x4 and those big whee larch gaps are ugly.

Has anyone worked out a good way of testing the springs? I can measure the free length. Is that a good indicator of condition? I could put a weight (the wife?) on each one and measure the deflection I suppose.

One last thing. Is it worth powder coating them? Or does it just shear off when the spring flexes? Is it worth painting them with anything at all? Like any other metal part they must rust. On the chassis that I am replacing the front turret bolts that the suspension arms slide onto have rusted right through on one side! I have never seen a spring rusty like that though.

Any thoughts?

[Foxie]

Berni,

The spring rate is determined by the wire thickness, number of coils, dia of coils, and material elasticity. If these are the same for a spring, even though the free lengths could be marginally different, the rates are the same. There is a formula which gives the rate, but I have found the practical check more accurate.

I can send you a photo of my spring rate measuring rig, which uses a 5' side triangular frame, a bathroom scale, a measuring tape and some concrete blocks.

Springs can to "settle" over time, but the rate does not change.
I have changed springs a lot, and found that the "direct replacements" supplied are often different. I previously corrected some of these by cutting and refinishing the ends, but now use Spax shocks with adjustable platforms to get fine adjustment of the ride heights.

Sean Murray

[berni29]

Hi Sean

It is interesting that even if the free length is different that the spring rate remains the same. I have a pet hate which is one side of the car sitting lower than the other, or a low corner. I am an expert at "fingers under the wheel arch" comparisons.

I can set up a similar rig to that you describe (thanks for the pic) and give it a go.

Many thanks

Berni

[john.p.clegg]

Berni
If you are old enough to rember Blue Peter,follow their lead and find the right size squeezy bottles and use them to make shrouds for your springs,believe me(i've done it) it's a great idea and keeps the road muck off,it also helps to bear in mind rear m/cycle dampers for the comfiguration
John

[john.p.clegg]

P.S.
I have had approx four sets of front springs,all giving different ride heights,the only ones thet did the job was lotus own
John

[berni29]

Hi John

Good idea. I remember Blue Peter very well. Squeezy bottles are a thing of the past though. At least in the UK they are. They were made of a nice soft thickish white plastic that was very shatter resistant. The nearest modern equivalent might be a plastic lemonade bottle, but I think that would be far less resilient. I suppose that it could be painted with underseal. That might help.

Berni

[bvt]

Also remember to set the ride height as per the manual...
Don't tighten up the wishbones till the body is on and correctly weighted etc etc

I assume +2s are the same as baby Elans.

[berni29]

Hi There

How do the wishbones affect the ride hight? Even when tightened up they should be able to move freely. I cannot see anything in the standard suspension that can make a diffence to the ride height except the springs (and tyres for the pedantic). Or have I mssed something?

Berni

[berni29]

I sure did miss something. I missed the "i" out of missed. Typical.

[niallf]

Hi Berni,

I think the theory goes that if you tighten the wishbone bolts without the car correctly loaded, then you clamp the bushes at that ride height. Then when you load the car correctly there is torsion put into the bush rubbers. This puts unnecessary strain on the rubbers causing premature failure, and may affect the ride height, I guess.

So wishbone bolts should be loose until everything's on, then tightened at normal running height.

Hope this makes sense !

Niall.

[john.p.clegg]

Berni
I don't know where in the U.K. you are, but up here in Manchester at Asda,Tesco etc,, they sell their own brand(cheap) washing up liquid and some of them are good fits

John

[berni29]

Hi John

Do you know something, I go to the supermarket once in a blue moon, and never near the household stuff! I had better change my ways! Thank you for that information.

By the way, I cannot agree with the torsion in the bushes theory. I just do not think that it would make a difference. The shear forces wouldn't be that good for the bush either. I use polybushes, and the fit is tight when you move the A frame up and down but not to a meaningful extent. They must loosen up after a while in any case.

All the best

Berni

[lotusanglia1965]

:ph34r: Suspension bushes of the metalastic type must be tightened at normal ride height or they will rip apart.on a normal car this would happen very soon,but as the elan is so light bushes tightened in the wrong(unladen) position will affect the ride height slightly.Anyone using polybushes can disregard the above as they are not bonded,but designed to revolve on the steel sleeve.It amazes me how many people ruin new rubber bushes by torquing bolts with suspension unladen. cheers,
Martin

[berni29]

Hi Martin

OK, I see how you could be right. You are saying that the inner sleeve inside the metalastic bushing is gripped so tightly that it does not move and the outside of the bush moves in an arc around it. So if you tigthen up with the wheels off the ground you put too much movement through the bush for the rubber to cope (in the longer term) when near the bump stops. I always thought that the inner sleeve was free to move in relation to the bolt. Now I think about it that must be wrong because it would offer the opportunity for the bolt to rotate, and that would be bad.

Many thanks for setting me and at least one other person (the plus 2 owner who lives up my road and wondered about this as well) straight on this.

Berni

[lotusanglia1965]

:unsure: Hi Berni!
Sorry if my last post came across a bit strong! yes,you've summed it up,if the bolt is left loose enough for the steel sleeve to rotate,the bolt could work loose! also,it will wear as steel rotating on steel does.It is awkward to tighten bolts when loaded, but is crucial. cheers,
Martin