S4 / Sprint Ground Clearance question

[stuartgb100]

A couple of recent comments have got me to thinking that my Sprint sits a little "nose up".

It's got adjustable rideheight all round.

Because the underside of the cill is curved at the extremeties, it can be a little subjective to measure from there, and anyway, I'm not after a pure clearance question ..... more a need to know how Lotus balanced the weight between front and rear.

So if anyone has a standard S4 or Sprint, could they please tell me this:

If the car is on level ground, and a spirit level is placed on the horizontal chrome door trim just above the lock (but in the middle of the door)
.......... does it read level ???

On mine it doesn't. It needs to be lifted at the rear, suggesting the rear is sitting lower.

Not scientific, I know, but just looking to set up some bankers to work from.

thanks and Regards,
Stuart.

[elansprint]

stuart mine was the same & had a nose up attitude but i have changed to adjustable ride height & lowered the front slightly so i cannot give you a measurement but it looks better now
Ian

[steveww]

I have set the ride height on my S4 such that the suspension arms are level as per the assy diagrams in the workshop manual.

[bcmc33]

Stuart,

I've always thought my car was a little nose up. I thought this was maybe an optical illusion due to the wheel arch tyre gaps. As a matter of interest the front wheelarch on my car sits about 50mm higher than the rear. I?d be interested to know if this is correct.

Using your method, my door trim rises 10mm from back to front over the comple length of the trim, and putting a spirit level on the door opening and floor seems to give the same results.

Taking Steve?s line, my lower front wishbones are definately not horizontal ? if they were the front end would sit down by about 20mm.


Brian Clarke
(1972 Sprint)

[pereirac]

This isn't because the front suspension is tightened with the wheels off the ground is it? I seem to remember Lotus using this trick to get the Elan headlamps higher to get the cars into the US. Jack the car up at the front, loosen the front suspension wishbones and then retighten them with the wheels hanging down. Once the car was safely with the dealer, the suspension could be readjusted with the car on the ground to get the car level again...??

[stuartgb100]

Carl,
I'm pretty certain that when I changed the suspension, I tightened the suspension with the car on the ground.

Brian,
I measure 11-12mm on the door chrome (higher at the front).
My wheel arch clearances (taken central to the spinner) are as follows:

FNS 603 FOS 592 RNS 527 ROS 529

As for the bottom suspension arm being horizontal:

The FNS is 15mm out of level, the FOS is 10mm out (in both cases needing the adjustable suspension to be lowered to get the arm horizontal).

Regards,
Stuart.

[tyasman]

This subject interests me! I have just bought a '68 S4 and I suspect the suspension/ride height is all wrong. If you bounce on the front of the car, the suspension is very stiff and the shock absorbers squeak (as you may tell, I am not a technical person!). At the rear, the suspension is soft, easily compressed, and it bounces back into position. I am trying to find out what it should be like. but have no reference points. I also think the front of the car is too high, with a distance of 17.5" from floor to centre of bumper. Is this right? Having said all this, the car seems to drive OK, but then again I don't know what it should be like. I'd appreciate any comments.

[bcmc33]

I?ve just completed a partial front suspension rebuild with new upper wishbones, ball joints and trunnion bushes simply to address an MOT failure.
All the bushes were loose when re-assembled, and the suspension jacked-up to the normal road height before re-tightening.
One thing that did surprise me was the fact that the suspension would only jack up a little way past the normal road height before continuing to raise the chassis. This made me think that the shocks are shot ? although I don?t notice anything wrong when driving.
I have a new set of adjustables, but no suitable springs yet, as the complete job was planned for the winter.

I measured the lower wishbones and they are nearer to 25mm out of horizontal. When I bounce the suspension it does not move anything like 25mm.
My wheel arches measured from the wheel centre are:
FNS 352, FOS 352, RNS 305, ROS 313.

And the underside of the front bumper is 17.5? off the ground.

Scaling from the workshop manual front suspension drawing shows that the lower wishbones should be 191mm (7.5?) off the ground.
My rear bushes are 215mm (8.5?), and the shocks bushes 191mm (7.5?).

So in my case it is clear that the front of the car is 25mm (1?) to high.

The next question ? what do I need to do to correct this situation?


Brian Clarke
(1972 Sprint)

[steveww]

With the standard suspension I found that the front of my S4 was about 1" (25.4mm) too high. This was only corrected after fitting adjustable spring platforms. Not sure why this would be the case, may be USA headlight height is the reason??

When doing a bounce test on the front and rear the front is a lot stiffer than the rear. AFAIK this is normal.

When setting up the suspension remember to allow for the usual load (i.e. you, full tank of fuel etc.) that the car will carry.

[rgh0]

The front suspension squeaking is normally the springs rubbing on the shock body or the dust shield.

Front always feels stiff compared to the rear to to stiffer spring and shock setting and front roll bar. Spax rear inserts also appear to need "to pump up" before they start working if sitting for a while whioch alos contribute to perceived rear softnew

The Front suspension only moves a little above normal ride height when jacking under the wheel due to a combination of stiff springs compared to the rear so that the car rocks diagonally when jacked and a roll bar transferring load to the other front spring.

If your ride hieght is too high and you dont have adjustable spring platforms then you need to change the spring.

cheers
Rohan

[bcmc33]

Thanks Rohan, that was my eventual conclusion regarding the spring factor.

But it still begs the question as to why the front is high with the standard set-up. Perhaps they really were all 1" too high after all.


Brian Clarke
(1972 Sprint)

[hatman]

But it still begs the question as to why the front is high with the standard set-up. Perhaps they really were all 1" too high after all.

I think that's probably right Brian - mine's certainly 'too' high at the front, having recently fitted 'new old-stock' Armstrong coilovers from Susan Miller.

[rgh0]

My S4 was too low when I first got it in 1976. The front springs had sagged and lost free length in 8 years and around 30,000 miles of use.

The Elan and especially Plus 2 front springs to the orginal design were very highly stressed and if not formed correctly and heat treated right were prone to sagging. I suspect most original front springs have been replaced at some time and often replacements were not made to the original specification changing the ride height.

Also many replacement front shocks over the years ( Koni for one) came with the spring platform in the wrong location versus the lower pivot also changing the ride height.

You really need to remove the spring and shock and measure them up to determine what the problem is.

regards
Rohan
PS I apologise for all the typos in the previous post - my 7 year old was hassling me as I was trying to type !!!!

[elansprint71]

Hey folks, don't forget that the body is separate from the chassis!
All the talk so far seems to relate to adjusting the ride height of the chassis; the body can be packed up at one end or the other and probably has been at some time by a DPO. Just 'cos the body looks to be at the "wrong" ride height/attitude does not mean that the chassis is!

[bcmc33]

My comments about the front end being 25mm too high related to the lower wishbone not being parallel to the ground had me thinking today about the obvious affect on the camber angle.
The manual says 1 degree positive ? I did a check to find that both wheels are just under 1 degree.
When the lower wishbone position is corrected the camber angle could be about 1.25 degrees (if my calculation is correct, of course).

Unlike the other front suspension angle specs, the manual does not mention a tolerance for the camber angle ? so the question is: does an angle of 1.25 degrees matter?

I?m sure there will be some useful information out there?????????


Brian Clarke
(1972 Sprint)