Lotus Elan

S4 Front ride height

PostPost by: rmd24 » Mon Nov 08, 2010 3:33 pm

I know there are a million and one threads on this in the archives but as far as I can see none of them actualy describes how to adjust this.
As I understand it the lower wishbone should be roughly parallel with the ground, mine however is in a pronounced droop position.
The workshop manual describes the procedure for tracking which requires the laden ride height to be 15.5 cms at the "suspension fulcrum" I assume this means the lower wishbone pivot point.This setting does produce a level lower wishbone .The UNLADEN measurement on my car is approx 18.5 cms which reduces to about 17cms with passengers aboard.
In an attempt to rectify this I slackened the wishbone to trunnion bolt and the upper and lower wishbone to chassis bolts. I then applied suficient weight ( a 14 stone mate and a 13 kg sack of birdseed) to bring the height down to 15.5cms and retightened all the bolts. Somewhat as I expected ,when mate and birdseed were removed it returned to its original height of 18.5 cms. What have I not done that I should have done?

Roger.
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PostPost by: alan71 » Mon Nov 08, 2010 10:28 pm

The standard front suspension isn?t adjustable for ride height.
You would need to buy new dampers with adjustable spring platforms.

Alan.
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PostPost by: paddy » Mon Nov 08, 2010 10:58 pm

Tightening all of the bolts with the suspension at the correct laden height is the right thing to do, but it doesn't change the ride height at all - it just ensures that there is no stress in the rubber bushes.

Have the springs been replaced at any time? As Alan says, there is no adjustment but with the correct springs it should just be right. Or, perhaps, the dampers have been replaced for ones with the spring perch at a different position, without any compensating change in the springs.

If the springs are new, allow some time for it to settle before coming to any conclusions.

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PostPost by: rmd24 » Tue Nov 09, 2010 9:25 am

Well, that's rather what I thought. I couldn't really see what effect my actions were going to have but I was given to understand that that was the way to go about it. Apparently not. I suspect that the springs are possibly not the correct length, the car has been comprehensively restored by the previous owner so I guess I need to speak to him about it.
Thanks,
Roger.
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PostPost by: elansprint71 » Fri Nov 12, 2010 11:20 pm

One of the million and one threads on this subject talks about packing up the body from the chassis to avoid the cam cover/radiator hitting the underside of the bonnet. If the chassis and body have been separated/replaced at some this is yet another set of imponderables to chuck into your Lotus mix. Particularly if it was done in haste, or by an idiot (for which read DPO) :twisted:
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PostPost by: rmd24 » Sat Nov 13, 2010 9:29 am

I am pretty certain that the problem is not caused by the body and chassis having been seperated. The chassis has been replaced but the point that I am using for measurements is the bottom of the front cross member so is not affected by a packed up body, so I will have to approach the problem from a different direction.

Regards,

Roger.
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PostPost by: ivor badger » Sat Nov 13, 2010 11:12 am

To be exact, you must tighten the bush bolts with the car sitting at its ride height even if it is wrong. Otherwise as pointed out, the bushes are under torsional strain and will fail.
The only way of adjusting the ride height is through the spring length or adjustable spring platform dampers. As your car has fixed dampers, that leads one to suspect the springs are wrong. Either wrongly made or the wrong springs for the car (ie +2?).

The ride height is critical because it sets the front roll centre and that can dramatically affect the handling and driveability. The Elan front wishbones are quite short and thus a small ride height adjustment can have a large effect on the roll centre position. Effectively the lower you set the roll centre, the less feel the car has. Bought one car and the adjustable spring platforms were set at the lowest possible setting with some strange handling characteristics. darted all over the road on bumps, well it was using the bump rubbers as springs. Trailing throttle oversteer into corners and no feel from the front end. The more I raised the car, the better it became.

So find out why it is high, the simple one is check the springs and while they are off, check the damper diemensions to see if the spring platform is in the correct position, possibly the wrong dampers(again +2?).

Having the car scrape the road might be fine on the track or supposedly improve the looks, but it will have a detrimental effect on the handling on the road.
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PostPost by: elancoupe » Sat Nov 13, 2010 11:28 am

There are several different spring lengths for the Elan, and it is not uncommon for the DPO to fit the wrong ones. I have seen numerous cars that sit too high in the front for this reason.
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PostPost by: lotus66 » Sat Nov 13, 2010 10:32 pm

Hi, am in the middle of a chassis off rebuild on an S4 with all new Spyder components. The ride height has all to do with spring length and adjustable spring perches as was stated by Alan. I have standard length Elan springs in the rear and Tony Thompson "comfort" adjustables up front. The car has a noticable rake to it, and sits higher than I would like. To get the car lower, I'll have to change to TT's "fast road" springs and a shorter spring in the back. My goal is to have the car low, but with no real rake to it. Unless you go super low, lower than the fast road spec for example, you'll have no handling problems whatsoever. Get a competent shop to line up your front end and make sure, regarless of wheel type, that your wheels are true and high speed balanced. Tightening things up under load is very good advice. If your car darts and wanders, it probably a question of camber and other wheel adjustments. Check the toe in/out. tire pressure as well is pretty critical as well. FYI, one lotus pundit, when I was asking all these questions years ago, suggested I relocate all my supension pick up points, f & r, to lower the car. Ummm, no.
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PostPost by: rmd24 » Sun Nov 14, 2010 4:20 pm

Thanks for the input. I'm convinced that incorrect springs have been fitted in the not too distant past. I noticed that when I weighted down the car to the recommended laden ride height the gap between the spring coils was only about 5mm and it seemed to me that at full bump the spring would in effect become solid. The PO carried out a restoration based on replacing what needed replacing and refurbishing everything else. He did not replace the front springs but they appear to be in very good condition suggesting that they had been replaced (wrongly)just prior to his acquisition of the car.

I have no wish to make the car any lower than standard but at the moment it looks a bit like a speedboat with its nose out of the water but more importantly I have the feeling that the handling is adversly affected. Not having had any previous experience of Elans I can't really form an informed opinion but I feel that it is somewhat vague on turn in and quick change of direction. Not quite what I would expect from an Elan.

I guess the solution is to remove and measure the springs and if necessary replace them.
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PostPost by: higgyuk » Fri Nov 30, 2012 12:24 pm

NOTE the REAR ride height can be affected by the position of the spring in the cup if it slips round away from the stop ridge in the strut holder -it wasn t my chassis higgyuk
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