Timing belt frequency (khz) question? f355 | FerrariChat
Buy

Timing belt frequency (khz) question? f355

Discussion in 'Technical Q&A' started by SoCal1, Apr 29, 2014.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. SoCal1

    SoCal1 F1 Veteran
    Owner Silver Subscribed

    Jun 14, 2011
    8,630
    SoCal LA/OC/New Mexico
    Full Name:
    Tim Dee
    #1 SoCal1, Apr 29, 2014
    This is for a f355.
    I have a sonic meter I used on bike primaries and blown hot rods and wanted to see if I can utilize it on the fcars

    I been looking through the workshop manual and maybe I missed it.
    Saw set the tensioner gap to 2.5 mm.


    Does Ferrari or anybody specify a sonic frequency for setting the 355 timing belt tension? I have seen it listed for later models

    Does it get checked on what span or multiples ?

    Are span reading acumulative to the specified frequency? Not sure of Ferrari protocols due to cam position etc.

    Any thought suggestions greatly appreciated

    :)
     
  2. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    39,162
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    #2 tazandjan, Apr 29, 2014
    Tim- Ferrari did not start recommending frequency tensiometers and publishing belt frequencies until the 360 and 575M were introduced. Before that, they used a Steiger tensiometer that measured depression across a span, a much less accurate way of measuring belt tension.

    Several of the pros have developed their own tables of frequencies for the 3X8 and F355 through trial and error and, possibly, comparison with Steiger measurements. For obvious reasons, they do not publish those tables developed over several years. If you have a good working relationship with one of those experts, he might be willing to give you what you need if you promise not to divulge the numbers.

    On the 65 degree V12s, there have been two sets of published numbers, one for a long span only, and one for the average of the long and short spans. No idea what is best for the F355.
     
  3. SoCal1

    SoCal1 F1 Veteran
    Owner Silver Subscribed

    Jun 14, 2011
    8,630
    SoCal LA/OC/New Mexico
    Full Name:
    Tim Dee
    #3 SoCal1, Apr 29, 2014
    Last edited by a moderator: Sep 7, 2017
    Thanks Terry

    I would ASSume the 360 would be very similar (same belt). Tension should be a basic length, width mass calculation then average it over spans possible
    Again I ASSume LOL

    Unfortunately most everyone i known in the industry has passed away or retired at this time


    :)

    EDIT

    I did find this in the 360 man.
    Image Unavailable, Please Login
     
  4. finnerty

    finnerty F1 World Champ

    May 18, 2004
    10,406
    #4 finnerty, Apr 29, 2014
    Call up the technical department of the belt manufacturer (Gates, etc.) ---- they will likely have generated test tables for cross-matching belt tension specs of force / deflection vs. frequency for all of their belts. If you can provide them with one spec, they should be able to correlate it to the other corresponding spec and provide it to you.

    An internet search (or visit to the manufacturer's website) may even pull up a publicly available published version of the data :)
     
  5. SoCal1

    SoCal1 F1 Veteran
    Owner Silver Subscribed

    Jun 14, 2011
    8,630
    SoCal LA/OC/New Mexico
    Full Name:
    Tim Dee
    #5 SoCal1, Apr 29, 2014
    Thanks :) I do have access to all the gates tech.
    What was told to me was

    Formula:
    T = 4 x M x W x S2 x f2 x 10-9
    Where:
    T = Belt span tension (Newtons)
    M* = Belt mass constant (g/m)
    W = Belt width (mm) or number of belt strands
    S = Length of the span to be measured (mm)
    f = Natural frequency of the belt (Hz)

    *Units of mass constant M for synchronous belts is g /(m)(mm) or g /10 cm2 along the belt pitch line. Constant M for V-belts represents the
    weight in grams of a 1 meter length of belting with a correction factor
    applied to compensate for internal bending resistance.



    Really what I am looking for is secret sauce. If anyone has any feel free to PM me if you dont want to go public


    :)
     

Share This Page