Engine Hone

Cylinder Finishing for Deglazing and More

When it comes to maintaining the quality and performance of your engine, there is no better tool on the market than the Flex-Hone®. This tool has been known as the ideal method for cylinder wall deglazing and refinishing. The crosshatch that is naturally created from using the tool is the perfect plateau finish needed to increase oil retention and extend the life of your engine. Using the Flex-Hone will reduce Ra, Rpk and Rvk values and increase the bearing area which results in benefits of less blow by, less friction and a better sealing surface for piston rings. Brush Research is the inventor and manufacturer of the Flex-Hone tool. We pioneered the concept of a plateau finish. Do you need Flex-Hone Instructions? Are you having trouble selecting the right tool? Are you looking for a local Flex-Hone® Dealer? BRM is happy to assist you in any way we can to make your rebuild project a success. Please contact BRM by calling our Customer Service team directly or writing us an email. Happy Honing!

Why Use Engine Hones- The Flex-Hone@reg; Difference?

A Flex-Hone tool can create an ideal finish for deglazing applications. Often known as a "glaze breaker" hone, the flexible tool removes the glaze or smooth surface from a worn cylinder wall. How does the glazing occur? In gasoline or diesel engines, pistons ride up and down within the engine, while maintaining a tight seal via the piston rings. Over time, this movement against the cylinder wall creates a smooth finish. If the cylinder walls are too smooth, rings will not seat properly and instead, they will "skate" over the surface. Smooth cylinder walls will also cause oil to not adhere to the walls causing other problems.

The breaking in process is the most common way to install new piston rings. It is important that a small amount of wear occur between the rings and cylinder wall in order to seat the rings properly and ensure a gas-tight seal. Using engine hones create a 45 degree crosshatch angle of tiny grooves in the cylinder wall. These groves create the oil holding crosshatch as well as produce the proper friction needed to seat the rings properly.



Crosshatch angle is a highly debated and misinterpreted topic when cylinder honing is discussed. The crosshatch produced by the Flex-Hone® is a result of stroke rate versus RPM. The optimum crosshatch angle is typically 45 degrees. Most OEMs and ring manufacturers suggest the angle of the scratches in the crosshatch pattern be between 27 - 45 degrees. This angle is measured from the deck surface. The crosshatch angle should be consistent pattern throughout the cylinder. If the crosshatch angle is too steep the cylinder walls won't retain adequate oil to assist in the ring seating process causing the rings to pump oil and rotate too quickly. This often leads to increased ring and ring groove wear. Too shallow of a crosshatch angle can cause a chattering affect as the ring passes over the valley. This prevents the ring from receiving enough oil leading to extreme ring wear, ring break in time and the possibility of engine smoking with no ring seating.

Other Engine Hone Applications

The Flex-Hone® tool has become the common solution for finishing other engine components such as main bearing bores, con rod big end tunnels, camshaft bores or tunnels, valve guides, lifter bores, hydraulic lifter bores, head gasket dowels and water pump tubing. In addition to engine components, the Flex-Hone tool can also be used for brake cylinders, clutch and brake master cylinders and brake rotors. Flex-Hone tools are the perfect solution to many of your automotive cylinder maintenance needs. You may be asking yourself if a Flex-Hone finish is necessary on all of these components. Some argue that it isn't. The Flex-Hone® finish will improve engine component longevity and improve the life of components by reducing friction, reducing heat and retaining oil where it is necessary. Doesn't this sound like what most rebuilds are about? You decide.

For more information on Flex-Hone tool applications, check out the Flex-Hone Blog!