The Flex-Hone® for Stroker Engines

Stroker kits are aftermarket automotive assemblies that increase engine displacement by lengthening piston travel. Along with a stroker crankshaft that lets pistons travel farther in engine cylinders, they include connecting rods, bearings, and piston rings. To increase displacement in stroker motors, the crankshaft moves the crank pin further away from the center of the axis of rotation. If the deck is flat and the cylinder bores sound, an engine builder can install a rotator kit over a weekend.

Auto Parts and Engine Tools
Armed with an Eagle 347 rotator kit from Summit Racing, Douglas R. Glad of Car Craft sought to do just that. The rebuilt 302 engine that he removed from a 1973 Ford Ranchero ran well, but deserved more power. After comparing several stroker kits, Glad chose one that provided “more usable torque” and came with rotator assembly components such as hypereutetic pistons. In selecting the right tools for the job, the Car Craft mechanic chose the Flex-Hone® tool from Brush Research Manufacturing (BRM).     

Cylinder Deglazing and Flexible Honing
After removing the stock rotator and pulling the pistons, Glad scrubbed the engine and readied the stroker crankshaft. Next, he installed forged pistons and rods. Noting that the cylinder bore was in “good condition”, the tuner used a “dingle ball hone” for cylinder deglazing. Although BRM discourages other names for the Flex-Hone® (such as ball hone), we understand that some users call the abrasive globules at the end of the tool’s flexible nylons filaments “dingle balls” or “dingle berries”.

Plateau Finishing for Piston Ring Seating and Proper Lubrication
Using what he described as a “pumping motion”, the Car Craft mechanic then “spun the flexible hone with a light honing oil until the bore had a crosshatch pattern.” We’re not sure if Douglas Glad used Flex-Hone® oil with its proprietary blend of honing and lapping oils, but the cross-hatch pattern that he achieved is ideal for oil retention. As the mechanic himself noted, this crosshatch pattern or plateau finish in the cylinder bore also “helped seat the new piston rings”.