Coil Over FAQ

[johnc]

The broad definition of "coilovers" are a shock or strut inside a coil spring sharing a common top or bottom mount. The stock 240/260/280Z front and rear suspensions have coilover spring/strut combinations in front and rear. A more common definition is:

 

Coilovers consist of a threaded aluminum collar, a stop (some kind of ring of metal) for the collar to rest on, a threaded perch that rides on this collar (and incorporates some kind of locking mechanism), a spring that sits on the perch (typically 2.5 inch diameter and anywhere between 6 and 12 inches long), and an upper hat for the spring. In addition, threaded body shocks (like Penskes, Carrerras, etc.) eliminate the stop and collar by having the shock body itself threaded.

 

You install coilovers by removing the strut from the car and the strut cartridge from the strut tube. Then cutoff the stock spring perch and grinding the weld smooth. Then the rest ring is slid down over the strut tube and positioned 5.25 inches above the bottom of the tube (where it is joined to the cast spindle part of the tube). The ring gets welded to the tube, collar slid on top of that. Then the cartridge is re-installed, followed by the new spring, topped by the hat. Re-install the strut.

 

There are advantages to coilovers:

 

1. The 2.5 inch diameter springs are relatively inexpensive and are available in a wide variety of lengths and spring rates.

2. The ride height can be adjusted very easily.

3. The narrower spring will allow for a wider Wheel/Tire combo.

 

And there are disadvantages:

 

1. Increased noise from the springs occaisionally contacting the strut tube or threaded collar and from the metal to metal contact of the spring and the spring perches.

2. Extra effort when lowering the car from a jack or lift to ensure the spring is properly seated in the upper spring perch.

3. Changes in ride height if the adjustable lower spring perches are not snugged down properly.

[scaotty]

This is a perfect explanation, and clears up some major questions I've had for quite sometime. I've also read the post titled "Step By Step Coilover Conversion" by theHelix112 which is much, much more complicated. But in my case, Im not ever going to race my Z so I'm not worried about perfect handling. My only goal is to be able to lower it to exactly where I want it. I already have KYB gas struts from MSA,and I'm going to be purchasing Ground Control coilovers. Is this procedure what I need? It sounds like it but I want to make sure.

 

Scotty

[johnc]

This thread is not a procedure, just a general description. The "step by step coil over conversion" thread is the correct procedure regardless of whether you race or drive on the street.