S2 suspension refresh - spring advice?

[danj.pdx]

Hello,

 

A couple friends and I are going through a '61 S2 with a pre-crossflow Cosworth. We'll be running it as fun street car on 4" steel wheels and skinny Pirelli CA67 tires. We've gone through the engine, gearbox, wiring, rear axle and are finalizing the suspension.

 

It was running Konis with what appear to be the original springs. The Konis are toast (one shaft bent), so we ordered a set of GAZ Series 2/3 coilover dampers.

 

Question - The front GAZ damper is 8.5" when extended. We tried a Falkner 125lb 11" spring. It appears to be too long when installed. Is 9" or 10" free length a better choice? 

 

Can anyone recommend spring rates and free length that would work with these dampers - with an emphasis on good compliance/balance?

 

Many thanks in advance!

Dan.

[MV8]

I assume these are the GS4-2030 dampers for the front without adjustable seats and they have 8.5" between the seats. It is rare to find a coilover spring application that doesn't require compression to install (not counting owner modifications with high rate short springs). The rate should be 95# with a free length of 12.43" and 9" between the seats. EDIT. 12.43"-9"= 3.43"x95#= 325.85# on the seats, /125#=2.6068"+ 8.5"=11. 1". Use an external spring compressor and you should be fine at fully extended but it will still sit high. Note the seat rate is reduced by the motion ratio of the suspension. Adjustable seats would have allowed you to set the ride height independent of the spring rate.

Edited Thursday at 07:30 PM by MV8

[danj.pdx]

@MV8

 

Thanks for your response. We're using the threaded GS4-2032 (for Seven series 2/3) so the bottom perch is adjustable. The 11" spring is slightly bowed when compressed to fit in the damper - even with the collar wound down to the bottom.

 

Thanks,

Dan.

[craig chima]

I have a pair of 10" x 200# springs in 1.875" diameter that I would sell cheap ($50).  The spring rate might be a little high on a street car but doubt that most people would notice the difference.   FWIW I run 250# on the front of vintage race cars with conventional S2 front suspensions as a point of reference

[danj.pdx]

Hi Craig, 

Those may be of interest, but we are trying to stay close to the original spring rates. We may try a 10" 125lb and see how that works with these dampers.

Thank you again for the response.

Dan.

[MV8]

What is the condition of the original springs? Too much work to restore?