Cylinder
wall deglazing is critical for the proper seating and sealing of new piston
rings in car engines. Left unbroken, the "glaze" on highly-polished cylinder walls
prevents piston rings from mating with the cylinder bore and providing an
adequate seal.
In used car engines, glazing is caused by the reciprocating
movement of pistons, which polishes cylinder walls to a smooth finish. Glazed
cylinder walls also cause friction and lubrication problems since engine
oil won't adhere properly to a mirror-smooth surface.
Cylinder Wall Glaze Breakers for Engine
Cylinders
RobertRO of CarDomain
knew that he needed to deglaze the cylinder walls of his BMW M30B34 engine, but
worried that he might "ruin everything" since he'd never honed an engine block
before. Honing, a type of abrasive machining, breaks the glaze on engine
cylinders and improves the geometric form of metal surfaces. Since rigid hones produce uneven or unidirectional grooves that can prevent optimum lubrication,
RobertRO choose a flexible hone instead.
Flexible Glaze Breaker Hones
Unlike
conventional honing stones, the flex-hone
produces a controlled surface condition and a cross-hatched pattern that's
extremely efficient at creating grooves for oil retention. This flexible glaze breaker
hone also "busts" the myth that cylinder honing is a risky business with the
engine block on the car and the crankshaft installed. Abrasive honing waste can
damage your car's engine, but only if you let the dust cover the moving parts,
and if you fail to clean
the engine properly with warm, soapy water.
Engine Block Honing for a Plateaued Cylinder
Wall Finish
Before honing
the engine block in his BMW 5 series, RobertRO rotated and covered the
crankshaft. Working on a "cylinder by cylinder basis", the amateur engine
mechanic then used the flex-hone to
produce the necessary plateaued
cylinder wall finish. Comprised of
abrasive globules laminated onto the ends of flexible nylon filaments, the flexible hone is self-aligning,
self-centering, and self-compensating for wear. It's also
easy-to-use, as RobertRO learned first-hand.
Once worried
about whether or not he could hone engine cylinders, RobertRO now remembers his
engine rebuild project with pride. "I was undecided," he explains, "should I
hone or not? Now, when I look back, I am positive it would have been a big
mistake not doing it."
This article originally appeared in the Flex-Hone Blog.
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