360 belt failure | FerrariChat

360 belt failure

Discussion in '360/430' started by Guss23, May 10, 2025.

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  1. Guss23

    Guss23 Formula Junior
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    Jun 11, 2017
    251
    Indianapolis
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    Jason Sharkey
    So, today, while heading to Mecum, I hit a pothole in my 360. It the engine immediately started to squeal and run bad. I nursed it into the parking lot and then had my Mechanic friend come and get me in the car with a trailer. After getting home, we pulled off the timing belt cover, and the driver side belt had broken. The belts only had six or 800 miles and we’re done in September of last year. Has anybody ever had anything like this happen? 
     
  2. fatbillybob

    fatbillybob Two Time F1 World Champ
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    Aug 10, 2002
    28,989
    socal
    Wow! Belt should not fail. Did something fogein hit belt on the pothole impact? We have seen some strange belt fails like one where a dime looks to have got caught and punched a clean circle through the belt
     
  3. Guss23

    Guss23 Formula Junior
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    Jun 11, 2017
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    Jason Sharkey
    it looks like the pulley locked up. It also looks like the tensioner was bent. I’m praying that I didn’t do any valve damage. We will see
     
  4. fatbillybob

    fatbillybob Two Time F1 World Champ
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    Aug 10, 2002
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    Improper install?
     
  5. Guss23

    Guss23 Formula Junior
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    I don’t think so.
     
  6. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    Oh well. This is gonna cost.
     
  7. imahorse

    imahorse F1 Rookie
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    Nov 25, 2017
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    Hitting a pothole should not have done that. I would imagine there was an issue going beforehand and that the pothole was the straw that broke the camel's back. Do you have some pictures?
     
  8. Guss23

    Guss23 Formula Junior
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    Jun 11, 2017
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    Jason Sharkey
    I will take pictures of the fail belt and pulley. I think you’re absolutely right about being a straw that broke the camels back. I was told there is a small chance that I did not do valve damage. I guess we’ll see.
     
  9. Lola360

    Lola360 Karting

    Oct 26, 2023
    134
    Bay Area, CA
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    Connor
    the fact you were able to "nurse" it anywhere with engine presumably still running I guess encouraging. But if indeed your belt was snapped, I don't see how you'd not have damage.
     
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  10. RedNeck

    RedNeck F1 World Champ
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    Jul 8, 2016
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    I'm trying to figure out how a belt with teeth can "squeal". Was there water in the pothole?

    I'm thinking may there was a misunderstanding on what's actually going on with the motor. If you broke a timing belt due to a "locked up" pulley (variator failure?), it would be banging and I'm not sure you'd be able to "nurse" it to a parking lot. I'm thinking the pictures will tell the story, something is just not adding up here.
     
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  11. RedNeck

    RedNeck F1 World Champ
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    OK, I've been thinking about this now that I have some coffee in me...Were the tensioner pulleys replaced when the belt service was done? That's the only thing I can think of that would cause the belt to squeal, and maybe that caused the belt to burn through, maybe affect the timing enough to run bad, then finally break after the car was stopped, unless the belt is just frayed and not completely broken. That's the only thing I can think of that would "maybe" not cause valve damage.

    If this is the case, which I'm guessing it is, that's a perfect example of why those tensioner pulleys need to be replaced every (or at least every other) belt service, preferably with HE parts. The cheap "lock n' swaps" just don't cut it, and if your "mechanic friend" did the service then he should be ashamed of himself and should be eating some of the cost on this.
     
  12. Ricambi America

    Ricambi America F1 World Champ
    Sponsor Owner

    BEFORE anything is disassembled, take a photo of the timing belt bearings as they are on your 360. There is only one correct orientation for the bearing install -- and this is whether you're using a Hill Engineering bearing, OE Ferrari bearing, or something made by a hack in east Timbuktu:

    https://www.ricambiamerica.com/guides/pt360_bearing_orientation

    Installed otherwise, there will be bearing-to-tensioner contact and it will seize/fail. This is not a trivial thing.

    (p.s. Even if they're removed, there are identifiable 'witness marks' that can confirm if the bearings were mounted incorrectly. We've seen these all too often in the 360 world...)
     
  13. yelcab

    yelcab F1 World Champ
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    How could anyone mount the bearing any other way? The two blind holes for tensioning do not go through the bearings so they have to be mounted facing out (so you can insert the tool to twist for tension). Boggles the mind!
     
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  14. Ricambi America

    Ricambi America F1 World Champ
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    Not everyone has the tool, and a lot of people seem to be in a gigantic hurry. 10 times out of every nine attempts to mount them with the incorrect orientation, the bearing will get bound up on the tensioner and bad things happen.
     
  15. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    How can anyone install brake pads backwards? I have seen it many times.

    This was not a part failure. This was an act of human intervention.
     
  16. Rifledriver

    Rifledriver Three Time F1 World Champ

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    Some people are more than capable of breaking a steel ball.
     
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  17. Jaymac

    Jaymac Formula Junior
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    Dec 18, 2020
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    Subscribed to actually see what happened here…
     
  18. WashingtonFerrari61

    WashingtonFerrari61 Formula Junior

    Jun 26, 2022
    476
    Northern, VA
    What a wealth of knowledge this forum brings to owners. The level of transparency this site can bring is comforting. I am sure this is quite an ordeal the OP is trying to sort out, but I am sure he is thankful for the insight. This type of issue is what most of us belt driven Ferrari owners hope doesn’t happen to us.
     
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  19. yelcab

    yelcab F1 World Champ
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    I believe it's human error.
     
  20. Jaymac

    Jaymac Formula Junior
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    Agreed. Interested in seeing photos and leading the modality
     
  21. Peter550

    Peter550 Rookie

    May 8, 2014
    37
    germany
    The problem I've already seen isn't that the tension pulleys were mounted backwards, meaning the adjustment holes are facing backwards. Rather, the tension pulleys are mounted in the wrong position. This means they're mounted too far up, and they're jammed on the tension pulley mounting arms, preventing them from rotating freely and locking them.
     
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  22. DBomb117

    DBomb117 Formula Junior

    Jun 20, 2019
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    Dimitriy
    This is strange, I've had a timing cover rattle loose after hitting a pothole and destroy my alternator belt, but I haven't heard of anything like this. The timing belts are very stout and are not known to break.
     
  23. RedNeck

    RedNeck F1 World Champ
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    I guess he's gonna leave us hanging...
     
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