I've been following this thread since it began because I want to lower my car (a 1999 Zetec 'Tour with E1 wheels).
I see there is a basic disagreement here regarding spring cutting. Some of you say that it's OK, so long as it's not done with a cutting torch. (Everyone seems to agree that cutting with a torch is bad because it could affect the temper of the spring, causing an unpredictable change in spring rate, and in extreme cases, a broken spring.) According to the spring-cutting members, if the cutting is done properly and exactly, it just shortens the spring to the same length as aftermarket lowering springs. It also increases the spring rate (i.e. it makes the spring "stiffer") because whenever you cut a coil off a spring, it takes more force to compress the remaining coils a given distance.
Other members are saying that springs should not be cut under any circumstances. They say it's dangerous, and it will cause poor handling.
It seems to me there are three main issues here: 1) will cutting a coil off the spring affect the structural integrity (strength) of the spring? and 2) will the cut spring fit properly in the strut base so that the force of the spring is evenly distributed on the base, just like it is with the stock spring? and, 3) will cutting a coil cause the strut dampers to wear out quickly?
As to issue #1, I asked the guys at a metal fabrication and hot rod shop here (Orange County, CA) if cutting a spring would affect its structural integrity. They said they are not metallurgists, but they have cut tempered springs for years (using a carbon disc blade) and never had one fail. They said the stock Contour spring is not progressive, so cutting off a coil would not noticably change the ride quality. This makes sense to me, since a spring is really just a metal rod that has been wound into a coil. Cutting a part of it off (without excessive heating) should not significantly affect the strength or integrity of the remaining part. We also have the example of the CEG member who lives in Hawaii (lucky dog); he cut his springs and has run them for 10k miles without a problem.
As to the second issue, I haven't found any information. I have looked at my springs (still mounted on the car) and I can't really tell if they would still fit properly (i.e. will they fit solidly into the strut base and be supported by the strut base for the entire first coil) if I cut off a coil. Does anyone know about this fit issue? I hope our member in Hawaii can answer this.
I also have found nothing useful re: the third issue. No one seems to know if lowering 1" will put undue wear on the dampers. Lots of people seem to think that lowering 2" will blow out the dampers, but does anyone know why? I guess we would need an expert in damper design to tell us that.
Sorry for the length of this message. It's a hazard of my profession (attorney).
