Cummins Marine Diesel Repower Specialists › Forums › Cummins Marine Engines › How to adjust early style QSB 5.9 v-belt tensioner bracket

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  • April 25, 2022 at 6:37 am #130837

    marks737
    Participant

    Hello.What is the proper way to tighten the v- belt tension on the early style QSB 5:9 bracket? Thanks

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  • April 28, 2022 at 5:18 am #130988

    marks737
    Participant

    Thanks.Ā  I wasn’t referring to the tension itself but how to actually adjust the belt pulley on the bracket which has a threaded rod with 2 nuts.

    April 27, 2022 at 2:21 pm #130971

    Gene Fuller
    Participant
    Vessel Name: Yorkshire Rose
    Engines: QSB5.9 380
    Location: Punta Gorda, Florida
    Country: USA

    The “proper” way is to use a belt tension gauge, especially if you do not have a “well-calibrated finger” to apply deflection pressure to the belt. I use a simple device that measures force and deflection at the same time.

    I believe Cummins has a spec, but a general idea for relatively small V-belts is the 10-10-10 rule. 10 mm deflection from 10 pounds of force for a span of 10 inches.

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