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Timing belt hanging over tensioner

Discussion in 'Technical Q&A' started by Irishman, Sep 20, 2025 at 2:00 PM.

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  1. Irishman

    Irishman F1 Rookie

    Oct 13, 2005
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    Kevin
    #1 Irishman, Sep 20, 2025 at 2:00 PM
  2. fatbillybob

    fatbillybob Two Time F1 World Champ
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    #2 fatbillybob, Sep 20, 2025 at 2:14 PM
    Install error. Without tension belts need to be fully installed on cams and tensioner with cams straight up on marks and #1 piston at TDC. Then tension belt. Then rotate motor in driven direction until you are back to #1 piston at TDC. Everything should look perfect and the motor spin easily and freely when doing this. 308 run best if cam timed but work just fine on assembly marks.
     
  3. Irishman

    Irishman F1 Rookie

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    #3 Irishman, Sep 20, 2025 at 3:46 PM
    Thanks, I agree. But where was the error?

    I installed the belts without tension. In fact, I would say it is impossible to install them unless the tensioner is fully compressed. The #1 piston was at TDC. All the cams were on the factory marks. The motor spins easily. And, in the picture, it is clear the belt is fully installed on the cams.
     
  4. tbakowsky

    tbakowsky Two Time F1 World Champ
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    Sep 18, 2002
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    Tom
    #4 tbakowsky, Sep 20, 2025 at 9:47 PM
    Why is your exhaust cam pully so much further forward than the intake? At least thats how it looks in the photo. Could be a perspective thing, but looking at the stud, it looks to be not seated properly on the cam snout..
     
  5. Irishman

    Irishman F1 Rookie

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    #5 Irishman, Sep 21, 2025 at 9:11 AM
    Thanks for the posts and private messages.

    The good news is that after a few engine rotations the belt is back on the tensioner. This happened getting the engine back to TDC.

    The bad news is I still have to take the whole thing apart. I discovered this morning that the exhaust pulley lip is cracked. It's not completely broken but I can pull the lip a little bit away. I would not want to roll down the road with it. Now I have to go find a pulley. I'll check everything carefully when I reassemble.


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  6. Ferrari Tech

    Ferrari Tech Formula 3

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    Wade Williams
    #6 Ferrari Tech, Sep 22, 2025 at 5:17 AM
    I have replaced the pullies before with billet aluminum pullies offered from a respectable supplier. I had the center bolt leak oil from both cams on one bank. I finally found the aluminum was slightly thicker and didn't allow the o ring to crush properly. I ended up using two o rings stacked and this stopped the leak. Just be aware of the possible issue if you use aftermarket. I have used them more than once and only had the one issue. Just check it so you don't have to go back in a second time.
     
  7. Irishman

    Irishman F1 Rookie

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    #7 Irishman, Sep 22, 2025 at 6:57 PM
    Thanks, but I am not following. Probably me. I do not recall any "leak" in this area. The pictures are showing the timing belts which are outside of a fluid area.
     
  8. Irishman

    Irishman F1 Rookie

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    #8 Irishman, Sep 22, 2025 at 6:59 PM
    I am trying to find a replacement pulley.

    First outfit (which I trust) is asking me if my pulley is plastic or steel.

    Mine is plastic.

    My ignorance. Why is the vendor asking plastic or steel? Is it bad to mix and match?
     
  9. RedNeck

    RedNeck F1 World Champ
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    #9 RedNeck, Sep 23, 2025 at 9:07 AM
    I'm guessing so they give you the correct one. Ferrari loves to change things mid year...If I remember correctly though, Hill engineering makes an uprated set of those. You'd be well advised to look into them before buying another Ferrari part
     

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