Flexible Honing for Engines

Do you rebuild gasoline or diesel engines? How about engine components such as valves, connecting rods, or crankshafts? Whether you’re a professional engine mechanic or a dedicated do-it-yourselfer, Brush Research Manufacturing (BRM) offers surface finishing solutions that are versatile, reliable, and easy-to-use. BRM Flex-Hone® tools can be used with a handheld electric drill, and do not require special training, expensive equipment, or complex setups or clean-ups.

Engine Cylinders

Flexible honing tools improve surface finish and remove burrs at the same time. Designed for inner diameter (ID) applications, BRM’s flexible cylinder hones are also known as ball hones because of their distinctive appearance. Made with abrasive globules that are permanently laminated to flexible nylon filaments, ball hones are self-centering, self-aligning to the bore, and self-compensating for wear. Always use these engine hones with a lubricant, preferably BRM’s specially formulated Flex-Hone® oil.

With its low-temperature, low-pressure abrading process, flexible honing produces a substantially flat surface that’s free of jagged peaks and cut, torn, or folded metal. The plateau finish that the Flex-Hone® imparts features a cross-hatch pattern of oil-retaining valleys for optimum lubrication. With used engine cylinders, BRM ball hones can be used to break the glaze-like finish that forms on cylinder walls. In this way, cylinder deglazing promotes proper lubrication along with piston ring seating and sealing.

BRM engine hones are ideal for cylinder wall surface finishing, but they’re not designed for heavy-duty material removal. Rigid hones can impart an uneven or unidirectional crosshatch, but honing stones are recommended for initial honing, cylinder resizing, and geometry correction. When selecting honing tools for cylinder wall surface finishing then, use the BRM Flex-Hone® to deglaze or surface finish the walls of cylinders that are not out-of-round or that require resizing.

Engine Components

As BRM’s Flex-Hone® Blog attests, professional and DIY mechanics alike are using flexible honing tools to deburr, deglaze, and surface finish engine cylinders.  These aren’t the only engine-related applications for Flex-Hone® technology, however, as BRM explains on the automotive industry page of its website. In addition to these on-line resources, MSB Tuning has documented its own experiences using flexible cylinder hones on engine components.      

In Flex-Hone Applications for Engines, the engine tuner describes the successful surface finishing of main bearing tunnels, conrod big-end tunnels, OHC camshaft tunnels, valve guides, DOHL lifter bores, and in-block hydraulic lifter bores. The engine shop also notes “miscellaneous uses” such as with water pump tubing. “If there is a hole and I need to surface finish it,” the author explains, “then I Flex-Hone it”.

Available for any type or size cylinder, Flex-Hone® tools come in a variety of abrasive types and grit sizes. For example, to surface finish a connecting rod, MSB Tuning used an 800-grit silicon carbide (SC) cylinder hone. To impart a very fine fish, the tuner talked about using aluminum oxide (AO) instead. For complete information about abrasive selection, tool selection, and ball hone use, download the Flex-Hone® Resource Guide from the BRM website today.