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A bit of history: In 1931, Clessie Cummins, founder of the Cummins Engine Company, drove across the United States to demonstrate off the viability of his new diesel engine. While descending Cajon pass in California (something that took real cajones in those days), the brakes failed on his truck and he and his pals barely survived the hairy ride. After that experience, Cummins devised the idea of an engine brake to supplement the use of wheel brakes on diesel trucks, especially for use on long downgrades.
Cummins developed the compression release engine brake in 1954 and shopped the idea around, but none of the major engine manufacturers were interested. His brother's son introduced him to the Jacobs Manufacturing Company, established in 1903 by A.I. Jacobs, makers of the world famous three jaw Jacobs Drill Chuck. The Jacobs company ran with the idea and marketed a successful line of compression release and other types of brakes. The firm split in 1986 and chuck manufacturing now takes place in Clemson, South Carolina, while engine brake producition remains in Bloomfield, Connecticut under the Jacobs Vehicle Systems name.
[/ QUOTE ]...stands to reason that a jake brake would work better with a Cummins engine.
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All of the brake systems made by Jacobs Vehicle Systems can accurately be called "jake brakes," not just their compression release engine brakes. They also produce the Jacobs Exhaust Brakes and Jacobs Driveline Brakes, both of which are nearly silent. The engine brakes are the ones that make that distinctive staccato sound, and if I could make a WAV, I'd include my imitation of it here.
The Jacobs company blames the loud noise you hear from passing trucks on the use of engine brakes in vehicles with poorly muffled or unmuffled exhaust systems (straight pipes, for example), exhaust systems that have been illegally modified or are poorly maintained, and/or truckers who simply enjoy making noise. Because of this, the Jacobs company feels that it's inaccurate, unfair, and maybe illegal to use their trademarked name in the generic sounding "NO JAKE BRAKES" signs, especially since some of their other jake brakes are quiet and noisy compression release engine brakes are made by other companies, too. These signs are often seen in residential areas adjacent to a highway. The federal government has required all vehicles manufactured since 1978 to meet noise requirements.
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Now the old air-over-oil retarders on the CAT motors were great (About the only thing I liked about those motors). They would hold a 129,000lb set of doubles back better than the Jake on my Cummins would hold 82,000lbs back. They added a few extra pounds, and you had to watch the oil temps, but they did a pretty good job.