Clutch Deadening Clutch/Gear noise

Discussion in 'Transmission / Drivetrain' started by cosworth, May 5, 2013.

  1. cosworth

    cosworth Member

    I've read a lot of threads on ways to quiet clutch/gear noise. Realizing that there is barely 1/8" clearance between clutch and inside top of the clutch cover I decided to make a 1/8" spacer. A machinist friend of mine made me a rough one out of 1/8" aluminum and now I have enough clearance to put two 1/16" layers of cork (using contact cement). Did it help - yes. Would I go to the expense of paying a machinist to make it - no. Using this requires slightly longer bolts. An alternative to this method is to buy a new clutch over and cut the top off to form what ever depth spacer you want. rsz_clutch_cover_spacer2.jpg

  2. jaguar

    jaguar Well-Known Member

    I took an alternate approach. I noticed that the noise got less and less as the teeth on the primary gear wore down so I helped them wear down even more by putting valve grinding compound on them. Worked like a charm! Once the noise reduced to very little I just spray cleaned the gear teeth and then applied grease. The rounded edges of the teeth (small gear only) had a more gradual contact with the matching teeth of the other gear to have less of a noise producing impact. Also as the teeth slide into place there is more surface area that the grease can help make a slick contact and produce less scraping noise.
    professor likes this.
  3. Fabian

    Fabian Well-Known Member

    or you simply add a centrifugal clutch which significantly reduces gear noise as it seems to act like a sound barrier. Win win situation because you get the user friendliness of a centrifugal clutch!
  4. jaguar

    jaguar Well-Known Member

    are you speaking theoretically or is there a bolt-on centrifugal clutch for the Grubee engine?
  5. Fabian

    Fabian Well-Known Member

    Do a Google search for:

    "Centrifugal Clutch - 48cc, 60cc, 66cc, 80cc - pull-start/pedal-start, 2 stroke"

    "Lubrication port > Modified Centrifugal Clutch - 48cc, 60cc, 66cc, 70cc, 80cc - pull-start/pedal-start, 2 stroke"
  6. Purple Haze

    Purple Haze Active Member

    I've been experimenting with different plastics compounds for the gears, as they are very quiet in operation. Unfortunately, I haven't found one that holds up long-term to high torque loads without lubrication. Delrin was my first choice, as it is self-lubricating, strong, and easy to machine: Too soft. Then I tried Rynite, which is used extensively by MSD, Remington, and others: Too brittle. GM for many years has used nylon over a steel inner casing for their cam gears with great success, but they are oil-bath lubed. Anyone have any suggestions? I believe something along this line is the answer to the noise problem, as well as the problem of grease slinging off the gears onto the clutch pads. Any advice will be appreciated.
  7. Fabian

    Fabian Well-Known Member

    A toothed belt drive system would solve all the problems of gear noise and grease issues.
  8. grinningremlin

    grinningremlin Active Member

    The two plastics I know of that might work, would be cost prohibitive, but if cost wasn't a consideration,...
    1) Meldin. I know it's used as piston rings, space age plastic, blah blah.
    2) Vespel. The next hardest plastic, meldin is replacing it so it's a little cheaper.
    Though the cost is INSANE.
  9. Fabian

    Fabian Well-Known Member

    MELDIN® 7021, 15% by Weight Graphite Filler

    Our self-lubricating grade, MELDIN® 7021, has 15% by weight graphite fillers, encapsulated by the base polyimide resin. With its low coefficient of friction and high heat resistance, MELDIN® 7021 provides our customers the best all-around choice for high temperature bearings, seals, and other low-wear applications.
  10. Fabian

    Fabian Well-Known Member

    Meldin® 7000 series polyimide shapes offer a new option for material design engineers who require the superior performance of an isostatic or compression-molded polyimide shape, without the extreme costs associated with Vespel®.
    Most customers have realized significant costs savings by testing and qualifying Meldin into applications that previously had been limited to Vespel. Meldin provides high performance combined with a more economical cost basis.