FINDING A BALANCE – THE ART AND SCIENCE OF ENGINE BALANCING

DirtSports December 2009

by Craig Perronne

Competent motor builders stack the decks in their favor by using every trick in the book to make their power plant last — and one of those “tricks” is balancing the rotating assembly of an engine.

Without a doubt, engines used in motorsports have extremely harsh lives and off-road racing offers one of the most brutal environments in which to operate. Constantly shifting RPM, heavy loads, hours of hard use and lots of dirt, increase potential for engine failure. That is why any competent motor builder stacks the deck in their favor by using every trick in the book to make their power plant last.

One of those “tricks” is balancing the rotating assembly of an engine. While this won’t increase horsepower, balancing adds longevity and reliability. Most critical components which rotate at high speed (such as tires and wheels) need balancing to keep vibrations down while providing proper rotation. The crank, connecting rods, and pistons are no exception. It might seem like a trivial process, but balancing greatly improves bearing life as it drastically reduces side loads. That is why every engine that goes into a race vehicle is, for the most part, balanced.

When assembling our well-documented VW stroker for the revitalized Project Elf. We wanted our 2,000cc mill to have every advantage available to it. Before heading out to Wik’s Racing Engines, we took our EMPI parts to long-time balancing gurus Automotive Balancing Services (ABS). Trusted by Gale Banks, Carroll Shelby, Ed Iskendarian, Don “The Snake” Prudhomme, and many others, ABS has an impressive list of clientele and enjoys a solid reputation. In business for over fifty years, ABS was recently acquired by Gale Banks Engineering and operates in the same facility as the diesel specialists but with all of the specialized machinery from ABS’ previous shop.

With our rotating assembling hand, the ABS team quickly went to work in a process that is a unique combination of science, skill, and art. Of course, the proper machinery and experienced technicians are also a mandatory part of that process. Follow along as the professionals at ABS show us what goes into properly balancing an engine.

crankshaft on balancing machine

weight removal

add weight


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