Tuesday, 2 February 2016

Why Spirolox Clips Are Used In Piston Pins?

In majority of cases, piston pins are retained with some sorts of clips. These are the situations when users prefer plastic buttons that can contact the cylinder bore. However, plastic buttons are a niche product. Most of the race engines and propulsion engines’ piston pins are retained by a pair of round wire circlips.

There are generally two ways to secure the piston pin that are variations on the same theme; mechanically, it is the easiest way of piston pin control as it requires no additional component- i.e. no circlips or other retention method. The use of mechanical interference in production engines is widely accepted and the two variations are interfering the pin in either the piston or con rod. Piston reveals the engine in which it resides. The crown tells about the bore, number of valves, and whether or not the fuel is injected into the cylinder.
In several examples, piston pins are kept in their intended position with circlips of varying design. Some of them are free to rotate within their grooves. But as usual, there are alternatives, and Spirolox clip is an alternative to round wire clips.
There are generally two types- single coil and double coil. Single coil is a circlip made from a small, flat bar instead of round wire. But the double coil is often used for more demanding applications. Double coil is strained axially in order to ease fitting and take up any axial clearance in the piston. As the clip has been strained plastically, it retains limited elasticity and tries to resume its expanded form. This does not work with round wire clip that centralizes itself within its groove that is also machined with a round cross-section.
Spirolox clip possesses more abutment area and bears against the end face of the Industrial piston pin. While manufacturing process, it is pretty easier to control the length of a pin instead of controlling the distance between gauge diameter.