348 timing belt tension reset and loose belt guide | FerrariChat
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348 timing belt tension reset and loose belt guide

Discussion in 'Technical Q&A' started by Ryanap333, Jun 26, 2022.

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  1. Ryanap333

    Ryanap333 Rookie

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    #1 Ryanap333, Jun 26, 2022
    My timing belt deflection is about 3/8". There is a little residue in the belt covers. The drivers side belt guide is loose and wont tighten. And I need more clear guidance on setting the belt tension. Do I need to be tdc for the adjustment? Any help is appriciated.
     
  2. yelcab

    yelcab F1 World Champ
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    #2 yelcab, Jun 26, 2022
    What does that mean?
     
  3. Ryanap333

    Ryanap333 Rookie

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    #3 Ryanap333, Jun 26, 2022
    As far as the guide being loose and rattling, the other side was loose about a year ago. I was able to tighten the bolt and secure the guide in place. The amount of residue in the belt covers doesn't alarm me. However, the belts deflection being more than 1/4" causes me to ask the question is 3/8" belt deflection inbetween the two cam gears reason to reset the tensioner? If it is then do I need to have the motor at tdc? My348 site says to turn the motor over 1/2 turn, then loosen the 17mm tensioner bolt and retighten. Does that mean 1/2 from tdc? Should i remove all the plugs so the engine turns over easier?
     
  4. yelcab

    yelcab F1 World Champ
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    #4 yelcab, Jun 26, 2022
    When was the last time the timing belt was changed? Typically, if the belt is old, retensioning it does not fix the problem because it soon comes back.
     
  5. fatbillybob

    fatbillybob Two Time F1 World Champ
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    #5 fatbillybob, Jun 26, 2022
    Do not retention old belts. That can end badly.
     
  6. Ferrarium

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    #6 Ferrarium, Jun 27, 2022
    I just did mine and there is no deflection to speak of between the cam gears on the same sine unless you use a pry bar or something.

    There is TDC and true TDC, you need true TDC as there is dwell at the top of the stroke, you can only get that with a degree wheel and a dial indicator. Shown below on mine. You have to degree the cams, not simply tighten the best which as mentioned ends badly it says so in the work shop manual as well

    Image Unavailable, Please Login

    Review FBB's excellent thread.
    https://www.ferrarichat.com/forum/threads/degreeing-cams.148917/
     
  7. Ryanap333

    Ryanap333 Rookie

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    #7 Ryanap333, Jun 27, 2022
    The belt was changed 5 years and 4k miles ago.
     
  8. yelcab

    yelcab F1 World Champ
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    #8 yelcab, Jun 27, 2022
    Then you do another engine out and change the belt and you will have to properly tension it at the end. Good luck.
     
  9. Ryanap333

    Ryanap333 Rookie

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    #9 Ryanap333, Jun 27, 2022
    Look my car is on a lify in my garage waiting for my bumper cover be repaired and then put back on the car. In the meantime, Ive replaced a busted cv boot and brake pads. Im in the process of moving from Alabama to California, there are no Ferrari techs nearby in Alabama. I can get the major done when I get to California but right now isnt the time. If anyone has a clesr amd accurate answer specific to my question about the retensioning of the belt and the loose belt guide it is appriciated.
     
  10. yelcab

    yelcab F1 World Champ
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    #10 yelcab, Jun 27, 2022
    OK,

    Bring the engine to TDC number 1 compression stroke
    Loosen the 17mm bolt that tensions the belt so that the tensioner can pivot
    Turn the engine over at least two turns. Take note of when the tensioner is at its most extended position.
    Turn the engine again to the point where the tensioner is most extended, stop
    Tighten the tensioner bolt to its torque spec.

    I don't know how you can get to that position with the engine in the car, but ... that is the factory procedure.
     
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  11. Ferrarium

    Ferrarium F1 Veteran
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    #11 Ferrarium, Jun 27, 2022
    The answer to your original question is in many responses in this post I suspect you just don't like the answer.

    Not tdc, true tdc there is a difference,, and don't retention an old belt and that much deflection between pulleys not not normal.

    If you retention the belt it will also alter your cam timing. Factory allows for plus or minus one degree. I'm guessing with all your factors you'll be outside that. Bad things can happen.

    Sent using FerrariChat.com mobile app
     
  12. GTO Joe

    GTO Joe Formula Junior
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    #12 GTO Joe, Jun 27, 2022
    As for your other question regarding the belt shoe being loose that item has a through bolt from the front cover to the rear cover. If you can't get it to tighten it is striped and needs to have a heli-coil or better yet a timesert installed in the rear cover. Again, something best done at engine out time. Since you are moving I would speculate a trailer transport to your new location so just let it sit until you move to the new location and get it done correctly. No way I would mess with the belt in the car. If you do you may need to bid on this- https://bringatrailer.com/listing/ferrari-348-2/
     
  13. Ryanap333

    Ryanap333 Rookie

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    #13 Ryanap333, Jun 29, 2022
    But the my348 website says the belt can be retensioned once iaw the factory specs. The bolt going through the belt shoe is as tight as i dare turn it. It seems more like a shim or washer would be the answer. There will be a local ferrari dealership nearby when i get moved.
     
  14. Ferrarium

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    #14 Ferrarium, Jun 29, 2022
    If the engines out of the car a belt costs $45. Why even gamble for $45. Plus you have no idea if that belt has been tension before depending on how long you've had the car. It's possible it's just the wrong bolt and it's bottoming out.

    Sent using FerrariChat.com mobile app
     
  15. Rupp3r

    Rupp3r Karting

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    #15 Rupp3r, Jul 3, 2022
    The belt can Indeed been retensioned once as Saïd in the workshop but they also state a mileage limite for the belt and I think it is 1500km..?
    In your case the belt is too old to be retensioned and if you do do then it may fail..
     

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