308 Belts - Is it specific to the pulley material? | FerrariChat

308 Belts - Is it specific to the pulley material?

Discussion in 'Technical Q&A' started by simple2code, Dec 3, 2005.

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  1. simple2code

    simple2code Rookie

    Dec 29, 2003
    31
    Because of the difference in camshaft pulleys (hard plastic,steel, or hybrid fiber), should a particular belt be purchased or are all the belts basically the same?

    Also, for the 308, are there belts available that use recent technological materials such as HSN (Highly Saturated Nitrile)? Does the OEM belts use this or are they basically the same type of belts made 30 years ago?

    Lastly, placing matchbook covers on the cam journal, by loosening only one cam journal (near pulley), could it cause the cam to bend?

    Thanks,
    Bb
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,932
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    It's not the camshaft you have to worry about when using the matchbook cover method (you're just pushing it over to one side of the combined bores - it's still in a very "straight" condition) -- it's the cam cap that is at risk. Threaded fasteners develop tremendous forces for relatively low torques -- you don't want to bend or crack the cam cap.
     
  3. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,288
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    Ferrari has updated the belts over time but I do not believe they have gone to the material you mention.
     
  4. Mark 328

    Mark 328 Formula Junior

    Nov 6, 2003
    510
    Orange, Ca
    Full Name:
    Mark Foley
    There was a post a couple of years ago that provided information that all belts are made by the same company (I think it was Dayco). I think the story went something like Dayco bought the Pirelli belt division and Pirelli made them for Ferrari. To me, the older belts looked better--they had more cloth around the teeth. The new belts don't seem to have as much cloth woven into the rubber.

    Mark
     
  5. robertgarven

    robertgarven F1 Veteran
    Owner

    Feb 24, 2002
    5,322
    Ventura, California
    Full Name:
    Robert Garven
    #5 robertgarven, Dec 4, 2005
    Last edited by a moderator: Sep 7, 2017
    BB

    These guys are better experts than I but I tried the cardboard and decided subsequently not to use it when I changed the belts next. For one it is easier to get the new belt on if you rotate the pulley a few degreees, something you cannot do with the cardboard inplace and as crazy as it seems I have heard of a case where someone forgot to take one out, leading to well consequenses

    Rob
    Image Unavailable, Please Login
     
  6. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,022
    Groton, MA
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    Verell Boaen
    Do NOT use a matchbook or similar thickness material, you will likely bend a cam cap. Use a double thickness of currency paper ($1 folded in half), or a business card.

    If you have a 2V engine, consider using Unobtainium's cam gear locks:
    http://www.ferrarichat.com/forum/showthread.php?t=40071&highlight=cam+lock+Unobtainium

    Tip, put the engine on the PM1-4 mark, then use a yellow grease pencil & put a mark on the edge of the damper, just where the inner edge of the rear cam drive gear goes below the damper. Now you can easily locate TDC & tell how far you've backed up.

    I've done belt jobs several times each way, & definitely prefer locking the cams.

    Lock the cams dead on the marks. Lock the tensioner in it's maximum outwards position.
    Slip the belt under the drive gear, then up around the tensioner & over the flange of the gear with the outside flange. Put a binder clip on the belt to hold it in place on the cam gear & another one to hold it onto the drive gear.

    Then back the engine up 1 tooth of the drive gear. This will put all of the slack in the belt on the long side going up to the gear with the inner flange. The belt will easily slip into place onto the gear.
     
  7. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,022
    Groton, MA
    Full Name:
    Verell Boaen
    Sorry, wasn't clear. A matchbook cover is way too thick.
    I normally don't recommend this type of locking to a novice because it's very easy to ruin a cam cap. What's worse, is that you don't find that out until down the road a ways when you discover that the matching cam journal is also ruined.
     

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