setting adjustable shocks

[grnicholson]

The PO of my car had fitted what looks like new adjustable shocks.  I leveled the front - no problem.  The back of the car was way out of level - half inch - and I screwing up the adjuster does not make much difference, it only compresses the spring to an unacceptable degree.

The car is on level ground, load is equal.  With both shocks at the same adjustment there is a half inch difference in length which is exactly the problem!  I am beginning to suspect faulty shock unless somebody can enlighten me.

Thanks for looking, information appreciated.

Richard

[jbcollier]

You don't say what model of Europa you have.  Europas do not sit "level".  Here's a guide for the S1/2 models:

https://jbcollier.smugmug.com/Lotus-Europa/i-7dZFVhs/A

Check your ride height first and then see how your springs are set.

[Grumblebuns]

Is the shock length the same with the preload completely loose? Are you sure that both rear springs have the same?

 

[BDA]

I have the same thought Grumblebuns had. I would take the springs off and measure them to see if they have the same free length. One spring could have sagged or they may have started off different lengths. It seem unlikely (but no more unlikely than they're being different lengths) but they could be different rates. Usually the rate is engraved or written on the face of the spring. If that's not the case, you can use a bathroom scale and a ruler to determine the rate.

This can open up a can of worms. If you need to get new rear springs, you should match them to the front so would have good balance. You would need to take the front springs off to see what you've got which is a bit of a bother since they are under preload (I don't remember that the rears were preloaded, but maybe my memory is inaccurate).

A lot of people use 250# (8" free length) springs in the front and 130# (13" free length) in the rear although if my memory is correct and there is no preload on the rear springs, the length is not generally an issue. That is quite a bit stiffer than stock, but it really is comfortable. If you were to deviate from these rates, I'd keep the free lengths the same and change both proportionately.

Hopefully, that's more than you need to be bothered with.

Good luck!

[EuropaTC]

Hi Richard,

When you say "level", where are you measuring from ?  At the front it's fairly easy with a cross member that you can use as a datum point although several other methods are also used.  At the rear it's more of a problem in picking the datum.  As I've got a workshop pit I can get underneath and measure at the rear end of the central spine which is one way of checking the chassis is riding level. I'd need to check back but I don't think it is perfectly level, it's higher at the rear IIRC.

Other places I've measured from are the rear chassis hoop, lowest point. Also the lowest cabin floor points at the wheelarches, the centers of front & rear bumpers and even wheel arches themselves.  Interestingly enough, the original owner of my car noted the latter dimensions in a notebook passed on to me, complete with tyres & pressures when measured, which has been helpful. 

To give you some idea of how mine is I've attached the one of my records.  The numbers you need for ride height are at the bottom of the page and should be easy to compare with yours. The car doesn't lie flat and comparing my numbers with the original owner's when it was new from Lotus, it never has done !

Brian

[pboedker]

 

That is a very nice "Europa Suspension Geometry" report you show there, Brian.

Do you have the clean report as a file to share? Or can I find it on some of our Europa manuals/documentation? I did make a quick search both on this site as well as Yahoo-group and 'lotus-europa.com' but without success.

[EuropaTC]

Hi Peter,

It's nothing special but I'm quite happy to share.  It's basically a collation of all common references I've found through the knowledgebase and other sources of how people have compared ride heights.  The bumper heights for example were commonly found in period road tests, which is a handy reference backwards.  However this format is mostly useful in monitoring your own car, to make it a universal reference it would need to account for tyres/pressures as obviously tyre wall plays some part in overall height. 

The original is a photoshop file but when I tried to convert it to pdf format through Photoshop this morning it seems to have a colour cast on it for some reason, hence this jpg copy, which looks white (as it should be !)

Brian

Edit to add:
 
I've just been updating my website with regards to the suspension part and generally looking back over my records.  I thought the background information might form a head start to anyone else who decides to fit adjustable dampers & springs. 

The first image is road test data for my car, I've added the S2 for comparison. The second & third are the recording formats, one for logging the spring perches and the other a revised format of the one previously posted for alignments. The only change to the latter is I superimposed the chassis backbone to make it easier to identify where I'd taken measurements because 12 months later I'll have forgotten !

[pboedker]

Thanks, Brian
I owe you one 

[Bainford]

Cheers Brian. I'll find this useful as well.

[grnicholson]

Hello
I stripped the suspension units and measured them - equal!  They are only 11'' free.  Far too short for road use.  I am advised to use 16'' springs.  They are on their way........  keep your fingers crossed for me.

Thanks for your input.

Richard in sunny Spain hoping to have the car on the road for March