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Miles Baker Goo Roo Vic 66 Mustang GT Convertible, 55 Chevy Bel Air, 69 Firebird 455, 69 Nova SS Clone
Posts: 1853 Reg: 08-2005
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Saturday, October 17, 2009 - 12:09 am, by: Miles Baker(Milesb)
Just letting you know the metallurgy mate. "Re-arched" leaf springs are notorious for lasting a year or so then slowly rising again. Read the material from a spring *manufacturer* like Eaton. It will probably echo almost exactly what I wrote above. Read posts on classic car forums of people who have paid to have springs re-arched. They are never happy.
Naturally if you cut a coil spring too far it is not going to stay in its pocket, and dumped Falcons are known for that. But "lowered springs" are shorter than stock also. In fact lowered springs are usually even shorter than a cut spring as lowered springs are made with a stiffer rate, so for the same ride height they will have a shorter height at rest. If you are dumping a car so far that the springs fall out, neither cut nor heated springs are going to stay in. In that case you are going to need dual rate springs or (for coilovers) additional "tender" springs. If you can get heated springs to stay in place it means their rate has been made so soft that the car will handle like a bucket of crap. And you are also lining up for a broken spring if they were heated that hot and weren't re-annealed and shot peened.
As I said, with regard to the metallurgy, I would prefer to properly cut *a* coil off a spring rather than heat it every day of the week, to drop a car one or two inches. Spring steel is not something to be messed with by guys with a press and an oxy. That is a true backyarder. Spring steel is made to have a memory. Cutting springs is MUCH more successful than messing with their metallurgy. If your heated and squished coil springs are not coming back to their original height, they are an accident waiting to happen. This is why there is VERY strict legislation against heating springs.