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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
    3,529
    Raleigh
    Full Name:
    Kevin
    #1 Irishman, Sep 20, 2025 at 2:00 PM
  2. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    29,270
    socal
    #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

    Oct 13, 2005
    3,529
    Raleigh
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    Kevin
    #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
    Consultant Professional Ferrari Technician

    Sep 18, 2002
    20,041
    The Cold North
    Full Name:
    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

    Oct 13, 2005
    3,529
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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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