456 GT - broken valve, mashed piston and cracked head | FerrariChat
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456 GT - broken valve, mashed piston and cracked head

Discussion in '456/550/575' started by Azzurro456, Sep 6, 2023.

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  1. Azzurro456

    Azzurro456 Rookie

    May 19, 2021
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    #1 Azzurro456, Sep 6, 2023
    I own a manual 1995 456 GT. Over the course of 8 months, around US$10k of work was done on the car, which went in with something that sounded like noisy tappets or clattering valves.


    Work carried out included removal of the head cover, identifying an issue with tappets on number 12, and a bunch of parts including 2 x tappet cover gaskets, 2x surge tank gaskets, 2x CK sensor cover gaskets, 4x tappet pads, 2 x manifold gaskets, 4 x cam o rings, 4 x cam seals, 1 x cam angle sensor. The head covers were painted. Other work was done to fix one of the fans, and a third fan was installed.


    When I took delivery, the engine was not running smoothly, but the mechanic said that he had “mostly” fixed it. Within 5kms of taking delivery, I hear a large noise from the engine bay, like metal popcorn popping in a microwave.


    I have had the engine removed and taken apart by a different mechanic. A spark plug and valve on cylinder number 6 has snapped, the piston has completely disformed, the cylinder and cylinder wall itself has warped. Only one valve on that one cylinder. The combustion chamber and head is damaged from shrapnel, a conrod is bent,


    I would be grateful for any thoughts you might have on what could have caused this, given the work carried out.

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  2. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #2 Rifledriver, Sep 6, 2023
    I am not sure thats going to be possible to say with the information you provided or even the information at your disposal. Not a big believer in coincidence but I will say accepting a car after repair that is obviously not running right with simply a comment he "mostly fixed it" was not a good idea. You deserved a much greater explanation at the very least. It may not be possible to find evidence to hold the other shop accountable at this point sorry to say. I can come up with scenarios but pretty worthless without proof.
     
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  3. INRange

    INRange F1 World Champ
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    #3 INRange, Sep 6, 2023
    I'm with Brian......it is anybody's guess at this point.....but one thing is clear looking at the other combustion chamber in view.....there appears to be a lot of miles on this engine. As to the work that was done.......you would have to connect the dots to a dropped/broken valve.
     
  4. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #4 Rifledriver, Sep 6, 2023
    An intake valve too. That is very odd.
     
  5. intrepidcva11

    intrepidcva11 F1 Rookie
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    #5 intrepidcva11, Sep 6, 2023

    "................given the work carried out!" Occurs to me that mebbe the work wasn't actually carried out
     
  6. scowman

    scowman F1 Rookie

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    #6 scowman, Sep 6, 2023
    Seeing the marks on the piston and head I would think a bent rod is possible.
     
  7. Azzurro456

    Azzurro456 Rookie

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    #7 Azzurro456, Sep 9, 2023
    Yes, I should have put the car straight on a flat bed and taken it to a different mechanic. Hindsight.
     
  8. Azzurro456

    Azzurro456 Rookie

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    #8 Azzurro456, Sep 9, 2023
    It's done 50,000 km, according to the speedo at least!
     
  9. Azzurro456

    Azzurro456 Rookie

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    #9 Azzurro456, Sep 9, 2023
    I suspect they made it worse!
     
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  10. Azzurro456

    Azzurro456 Rookie

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    #10 Azzurro456, Sep 9, 2023
    Yes, that is on the parts list as well...
     
  11. Azzurro456

    Azzurro456 Rookie

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    #11 Azzurro456, Sep 9, 2023
    The new mechanic's theory is something like a washer etc was left in the engine, given how rare an intake valve snap is. With all the mashing, though, everything in the oil pan was reduced to shrapnel. Some of which possibly made it out of the exhaust.
     
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  12. scowman

    scowman F1 Rookie

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    #12 scowman, Sep 9, 2023
    And into your cats. I would clear those too
     
  13. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #13 Rifledriver, Sep 10, 2023
    While it may be difficult it is probably not impossible to determine what all the pieces are. I once determined why a 355 engine blew up by examining the pieces with strong magnifiers. If you want to know you probably can. Not sure that will make a difference though.
     
  14. theunissenguido

    theunissenguido F1 Rookie
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    #14 theunissenguido, Sep 10, 2023
    Did you check the engine number before and after work was done ? Or did you mark the heads before ? Its not the first time engine or parts are swapped to worse ones.
     
  15. henryr

    henryr Two Time F1 World Champ
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    #15 henryr, Sep 10, 2023
    time for a LS swap
     
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  16. 2cam

    2cam Formula Junior

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    #16 2cam, Sep 10, 2023
    ^ I didn’t want to say it! ;)

    Seriously, though - Condolences to the OP. At least it’s a GT. GTA market values would make the repair bills for this a tough pill to swallow.

    2cam
     
  17. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #17 Rifledriver, Sep 10, 2023
    Do you have the tiniest idea how much work that is in a 456?

    You first suspicion is the motor or heads got swapped.....Really?

    It went in with a bad noise. This is just the eventual outcome.
     

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