Hi
I have just purchased a formula 27 built in 1996 running 20L pinto.seems well built but my knowledge is limited.It is fitted with what I assume is the normal spring over dampers.I have found that at speeds of 60ish if I hit a cats eye the front end drifts.It's scary on the motorway.I am running fyre pressures as advised of 12 psi .steering geometry is right,could someone advise me of basics setting for dampers e.g. number of clicks.The springs have been wound up and are showing about 2 inches of thread below the collar. Any adice gratefully received I have the full interlect of a hamster and a tool kit of a hammer an old file and a wooden clothes peg ish cheers in anticipation keithjavascript:icon(''

That sounds very wrong to me - firstly the amount of thread showing and secondly the tyre pressures!! Sounds like the springs are too short for starters if the coilovers are wound right up to give 2" thread showing. The tyres should be more like 18psi too - what size are the tyres??

Can you pop a picture of one of your coilovers on here??

[Edited on 8/2/09 by Paul TigerB6]

tyres 205 60R 68H super radial appear new car has only done 2300 miles

With that sort of size, your tyres do sound far too soft. Try upping the pressure to 18psi and see how it feels.

I'd suggest though that you really need to be looking at the coilovers still too. Can you measure the ride height both front and rear - pop the figures up on here. Measure from the chassis to the ground at the axle line (or as close to it as you can get at the rear). With so much thread showing on those shocks, it sounds like the springs are either too short or are in loads of compression and its jacking the front of the car up too high. Either could be giving the handling problems

shocks are in front of radiator nose cone is fixed difficult to photo try when it warns up to get access to rears they look like the ones on pagr 66 0fcomplete kit ace top right corner of kit parts direct ad.

Sounds more like bump steer than a shock problem.

I think you need to check the steering rack has been postioned correctly and that there is the same amount of turn left and right to check the rack has been cebntered correctly.

just my thoughts....

Paul

I agree with Paul Tiger B6 the tyre pressures are way too low.

18 PSI is a good starting point. I would then look at the damping adjustment - too little and it will jump around all over the place. try a setting in about the middle and work from there

Cheers

Mark

These ones?? Clicky

A pic showing the front suspension from the front would help also - the lower wishbone should be angled down slightly so that the outer balljoint and inner mounting point are horizontal (or very near to it). As Paul (the other one) says - it could be a bump steer issue also. Might be the track rod end is fixed to the wrong side of the steering arm - track arms of the steering rack should be parallel to the lower wishbones


[Edited on 8/2/09 by Paul TigerB6]

You say the geometry is correct... how do you know?

We had a similar problem - turned out to be toe-in... when set parallel it solved the problem.

It may be dump-steer but I wouldn't have thought so as it's a proper well-developed chassis.

Steve

rear height 160mm front 100mm cant get it out of garage to photo front. tracking was checked at my local garage guys switch on set to setting got from image sports who buid 27s

Wow thats a huge difference in ride height!! Thats measured off the horizontal chassis rails just behind the seat at the rear i take it?? More normal would be for the rear to be about half an inch higher than the front (which in itself seems pretty low).

I get the distinct feeling that your front springs are too short by maybe 2inches. Might be worth popping one off to measure the springs and shock up.

can the ride height be adjusted or will I need new springs dampers etc.Measure rear height directly below rear axel

Your front springs are either too short, or too stiff, probably a combination of both. To have that little ride height and that much thread showing then the springs are definitely WRONG.

They will need to come off. When you take them off find a way of fixing the front at a suitable ride height using dummy shocks (lengths of steel).

Ideally you need to weigh the various compnents and then take the measurements necessary to use Mike Capon's spreadsheet to calculate the correct poundage AND length required.

There may well be other things wrong with the suspension too, but those springs are as wrong as a pair of three pound notes, so they are goin gto have to come off anyway.

If you can't weight the various components then you can at least measure the existing springs. Measure their open length when they are off, then find a SAFE way of putting one on a bathroom scale and pressing down on it until it is compressed by a measurable amount. (for instance, 150lbs at half inch compression means they are 300lb rate).

John

Ah - the measurement needs to be taken off the chassis just forward of the live axle rather than off the axle itself.

Ride height is adjusted by winding the collars up and down the shock to compress or release tension in the spring - its the fact you have 2" of thread showing and the car is sitting pretty low that makes me think you could need longer springs.

dint explain myself well measured off the chassis rail below the axel.what height should the rear normally be can 1buy complete components to replace existing to suit type of car
cheers

A se7en chassis generally angles upwards at the rear so the ride height needs to be measured at the rear rail of the cockpit area (just behind the seats). Sounds like you are going to need some longer front springs for the front - about £60 a pair at a guess - poundage and length needs sorting out as Mr H says. Inboard springs operated by rocker arms on the Formula 27 isnt it?? I'd suggest contacting Image Sportscars and ask them what springs you need and whilst at it ask them about the open and closed length of the shocks they use and compare it to what you have. They should also be able to give you some ride height figures to set the car up roughly.

http://www.imagesportscars.co.uk/clubman/clubman.htm

I had a similar problem when i got mine on the road, it turned out to be all the springs where round up to high to give more ground clearance, which meant i had no downward travel on the shocks.