The Flex-Hone tool from Brush Research
Manufacturing (BRM) was featured recently in an episode of Motorz TV, a popular
DIY automotive television show hosted by Chris Duke. (Motorz TV also has a blog on CR4!) This how-to video was seen
across the United States on MavTV, Untamed Sports TV, and TiVo, and is
available worldwide on iTunes and YouTube. As Chris Duke explains in "How to Complete the
Rebuild of a Chevy 350 V8 Small Block Engine," the Flex-Hone is ideal "if all
you need to do is just freshen up your motor a little, or install new rings and
you don't have any major block damage".
Chevy 350 V8 Small Block Engine Rebuild
Unlike other automotive TV shows, Motorz is designed for car hobbyists who don't have a garage full of expensive
tools, let alone a lift. That's why in the second episode of the engine rebuild
series, Chris Duke took his used Chevy 350 V8 small block to a machine shop "to
get it all cleaned up". For engine cylinders that don't require reboring,
however, the Flex-Hone tool lets you "do a lot of the things we did in the
machine shop in your shop", Duke explains. By using the Flex-Hone with a
variable-speed drill or a drill press, automotive hobbyists can solve deburring,
deglazing, and surface finishing
problems.
Flexible Hones and Automotive Brushes
BRM's Flex-Hone is available in standard and
heavy-duty styles, and comes in a variety of abrasive types, grits, and sizes. Built
with a stiff metal stem and flexible nylon filaments, the tool features
abrasive globules that remove cut, torn, and folded metal from the walls of
engine cylinders. In addition to new and rebuilt motors, automotive applications for the Flex-Hone include
brake rotors, piston pin bores, wheel cylinders, and cam bearing bores. As
Chris Duke adds, "BRM also offers a complete line of automotive brushes to
handle the cleaning and finishing of all your automotive parts".
Flex-Hone Lubrication and Use
The Flex-Hone tool requires lubrication prior to use.
Although some users apply 1030W motor oil, BRM recommends generously
lubricating the tool with Flex-Hone Oil instead.
Never use solvents! "Within seconds of using the tool," Chris Duke demonstrates
on Motorz TV, "it will deglaze the cylinder and leave the surface with 20 to
40% valleys for oil retention, allowing the piston rings to seat immediately." To
create the proper cross-hatch
angle on engine cylinder walls, "accelerate the stroke rate for last few
strokes" but don't over-hone the cylinders.
Surface Finishing and
Cylinder Cleaning
After surface-finishing is complete, "thoroughly
clean each engine cylinder," Duke continues. First, use warm or hot soapy water
and a soft cleaning brush to remove any residue or debris. Next, dry the walls
with a lint-free cloth. When the engine cylinders are clean, use a fresh
lint-free cloth coated with light oil or mineral spirits. For a complete
demonstration of flexible honing, watch Motorz TV's "How to Complete the Rebuild of a Chevy 350 V8 Small Block Engine," starting at the 15-minute mark.
Author's Note: This CR4 blog entry appeared originally in BRM's Flex-Hone Blog.
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