308 Camshaft Timing Calculation ... help ! | FerrariChat
Buy

308 Camshaft Timing Calculation ... help !

Discussion in 'Technical Q&A' started by F308 MAN, May 17, 2008.

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

  1. F308 MAN

    F308 MAN F1 Rookie

    Jan 19, 2004
    2,907
    Isle of Man
    Full Name:
    Dave S
    #1 F308 MAN, May 17, 2008
    hello all,
    the cams have been off (http://www.ferrarichat.com/forum/showthread.php?t=196565) and upon reassembly, i simply fitted the new front cam belt one tooth out.
    the rear bank is spot on.

    so i thought i would do a little calculation (sorry, it's in millimetres)
    can anyone confirm that i am correct based on the following criteria ?
    i) camshaft belt pulleys are 89.3mm nominal dia. therefore circumference = 280.58mm
    ii) camshaft boss showing aprox. alignment marks are 31.8mm dia. therefore circumference = 99.92mm
    iii) cambelt tooth pitch = 9.6mm

    as a result of the above, i have calculated that if i am "one tooth out", the misalignment of the camshaft/camshaft cap marks would equate to 3.42mm

    can anyone confirm this ?

    many thanks,

    d
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,931
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #2 Steve Magnusson, May 17, 2008
    Yes, the arc length for a one tooth (camshaft) error would roughly be ~3.4 mm

    The other way to think about this is that there are 30 teeth on the cam sprocket so a 1 tooth error is 12 degrees of (camshaft) rotation, and

    pi*31.8/30 = 3.33 mm arc length error at the mark for each tooth (using your 31.8 mm size for the diameter where the mark is located).
     

Share This Page