Does Honing a Cylinder Make It Bigger?

Introduction to Honing a Cylinder

Honing a cylinder, as a machining process, is designed to enhance the surface finish and geometric accuracy of a cylinder, typically found in engine blocks or hydraulic systems. The process involves the use of a honing tool with abrasive stones to remove a minimal amount of material from the cylinder walls. This refining process not only corrects minor imperfections but also yields a cylinder that is slightly larger in diameter, although the change is often a small increment that must be monitored and measured to maintain acceptable tolerances.

Removing Material to Make the Bore Larger

When these techniques are applied to cylinders in various applications, such as boring cylinders for oversized pistons, the cylinder is typically bored to a diameter approximately two mils below the final bore size. The honing process then takes over, working to reach the final diameter while simultaneously creating a desirable surface finish. This method is particularly important in scenarios where precise control over the clearance between the piston and the cylinder is essential, such as in engine repair.

Difference in Honing Applications

It's important to note that the term 'honing' encompasses two distinct actions with regard to engine cylinders:

Precision Honing: This process is carried out on a specialized machine, where honing stones are run in a perfectly straight line. The tension on the cutting stones is controlled to achieve a consistent rate of material removal. The surface finish is a crucial aspect of this step in the process. De-glazing: This is a simpler process that involves using a deglazing tool on engine cylinders, particularly those in hydraulic systems or automotive brake systems. This tool scratches the surface to break the glaze, allowing for proper seating of new piston rings or seals. While it does not remove metal, it is essential for ensuring the surfaces adhere correctly.

The result is a cylinder that is larger but also more precise and better suited for its intended purpose. However, this larger bore can also lead to issues such as piston slap and excessive oil consumption, as the increased clearance between the piston and the cylinder can cause these problems.

Conclusion

In conclusion, honing a cylinder does make it slightly larger, but it is a controlled process that ensures the cylinder remains within acceptable tolerances for its application. Ensuring proper installation and maintenance practices after honing is crucial to avoid potential issues such as piston slap and oil consumption. Understanding the difference between precision honing and de-glazing is also essential for optimal cylinder performance.