Defenition and example of Coil Bind

Could some one Define what Coil Bind is. Give An example of coil bind and how to check for coil bind.

Thanks :TU:

 

Thanks Larry... I will keep this in mind and talk to the machinist about it.

 

That's pretty much what happens, and bind can happen in any coil spring. When the coils touch, the spring can't compress any further, and things can break. Coil bind at its worst is when the spring compresses so far that the coils bend around each other and interlock (hence the term "bind"), but this doesn't happen much in automotive applications.

Avoiding coil bind was probably why they went to dual valve springs in the first place. Increasing spring rate is generally done by using thicker wire, but you can only do so much of that with a single spring because as you thicken the wire you decrease the range the spring can compress before it binds. Adding a second spring increases tension without decreasing the compression range of the spring.

As a footnote, Honda uses special oval-shaped wire to make valvesprings in its racing engines (instead of the usual circular) so that they can thicken the wires and increase spring tension without actually decreasing the compression range of the spring. Likewise, the new high-performance "beehive" springs you might have heard of for the latest generation Chevy motor are tapered the way they are, in part to help prevent bind, I've heard.

Coil bind can also theoretically happen in a coil-spring suspension, though you'd have to hit a bump pretty derned hard to make it happen. If it does happen, though, you'll probably at least bend something irreparably. Coil spring suspension components for rally racing are specifically designed to avoid this condition, I've been told.

- Freed

 

Cam spring manufacturers should supply a minimum value (usually in the .060 range...I think) that should exist between two adjacent spring coils at full lift. Patton

 

Also called "stack" for obvious reasons.