It's important to get quantitative measurements. A friend on the
wheeltowheel mailing list said that Datsun Roadster springs were about
the spring rate that I was looking for and gave me a set. I spent last
night installing them, and they seemed to stiffen the car up. They
caused some other weird problems, but the car felt
stiffer. Unfortunately the car was also 3" higher in front.
The plan for tonight was to pull the springs, do some calculations and
cut them down so that the front of the car was level with the back of
the car (split the difference between the stock springs and the
roadster springs).
My first set of measurements were obviously wrong, they showed the
stiffer roadster springs to be softer than the MGB springs. So, I came
up with plan B. I took both sets out of the car. I measured the
distance from the floor to the crossmember with the car just resting
on the springs. I took four measurements, front and back for each
spring. I then lowered the jack until all of the cars weight (at the
front axles) was on the springs, and I repeated the measurements.
The results were that the MGB springs compressed 1.125" and the Datsun
springs compressed 1.25". Assuming 1200 pounds at the front axle, this
gives a spring rate of 533 lbs/in for the MG springs and 480 for the
Datsun springs.
I really expected the Datsun springs to be stiffer. the wire diameter
was really close (and hard to measure with paint etc), and while they
were 1.5" longer they had 6.5 coils versus 9 coils for the MG. This
would match the theory that they were about 30% stiffer.
I suspect that the car felt stiffer last night, partly because I
expected it to, partly because it just felt different, and with the
longer springs, I had a bit more preloading at static, and that may,
or may not have made a difference.
The lesson here is don't assume, measure.
--
I've found something worse than oldies station that play the music I used to
listen to. Oldies stations that play the "new" music I used to complain about.
lrc@red4est.com http://www.red4est.com/lrc
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