Engine Hones for Cylinder Bore Deburring and Plateau Finishing

The 2002 Firebird Trans Am was the last in a line of powerful Pontiac muscle cars. Introduced in 1967, the Trans Am competed with the Chevy Camaro, Mercury Cougar, and Ford Mustang during the golden age of big-block engines. In 2002, Pontiac added an 8-cylinder, 16-valve LS1 engine for the Trans Am’s final model year. This 5.7-liter, 347-cubic inch powerplant featured an aluminum block with aluminum heads, and a robust compression ratio of 10.1:1.

Trans Am Engine Restoration

For fans of the Pontiac Trans Am, restoring a used LS1 engine is a labor of love.  At ls1tech.com, an automotive website with forums for gearheads, a mechanic named ckpitt5 shared an engine rebuild story that’s familiar to many do-it-yourselfers. After making a build list and sending the big V8 engine out for machining, ckpitt5 explained why he chose to re-assemble the engine himself. “I have too much energy and money invested to trust that process to someone else,” the engine builder said.

Honing Stones vs. Ball Hones

After cleaning and installing new cam bearings, ckpitt55 checked the cylinder bores and made an important discovery. Honing stone “residue” left in machining marks would “eat” his new piston rings. Wiping down the cylinders was easy enough, but the bores still had burrs and “high spots” that would interfere with proper piston ring seating. That’s when this experienced engine builder used the Brush Research Manufacturing (BRM) Flex-Hone® tool, the engine hone for a superior surface finish.

Flexible Cylinder Hones for Deburring

BRM’s ball hone is a flexible cylinder honing tool that mounts in a handheld electric drill and removes cut, torn, and folded metal to produce a long-wearing surface. Self-centering and self-aligning to the bore, this flexible engine hone is great for deburring, a post-machining operation that’s critical in more than just automotive applications. By smoothing peaks and eliminating ragged metal edges, machinists and mechanics alike can remove burrs that impede the performance of machined parts.  

BRM Ball Hones for Plateau Finishing

The BRM Flex-Hone® tool also produces a cross-hatched pattern that helps oil adhere to cylinder walls. To promote optimum lubrication, the flex ball hone uses a soft cutting action that leaves the base metal undisturbed. The low-temperature abrading process produces a plateau finish that helps piston rings to seat properly – and without damaging their edges. BRM pioneered the concept of plateau honing, a surface finishing technique that also reduces seepage in hydraulic and pneumatic applications.   

How to Hone a Cylinder

For ckpitt5, running the Flex-Hone® “very briefly on the cylinder bore” produced a surface finish that also eliminated a stubborn cam bearing problem. Rebuilding a Trans Am engine takes time, of course, but honing cylinder walls with the BRM plateau hone is a job that engine mechanics enjoy. Have you used the BRM Flex-Hone® tool for deburring, plateau finishing, or cylinder wall deglazing? Share your automotive story with us by commenting on this blog entry.