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  •  » 289 breaking valves

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    6/19/2019 1:06 PM  #1

    cgomate
    FYI Addict

    Offline

    Registered: 4/01/2013
    Posts: 130

    289 breaking valves

    67 Cpe 289 C4 daily driver

    Had the engine rebuilt in Oct 2018 at a shop I've been dealing with for 15+ years.
    . 
    In April, the #6 Ex valve broke at the shaft under the spring.  Machine shop fixed it.  Two weeks later the rocker on that same valve snapped.  Machine shop gave me a new one and i replaced it at home.

    Car was running great until yesterday.  Really bad noises from the motor just leaving the parking lot at work.  I pulled the driver's side valve cover earlier today and now it looks like the #5 exhaust valve has broken at the shaft under the spring just like the previous one...

    What might cause this kind of failure?



     

     

    6/19/2019 2:07 PM  #2

    Rudi
    Senior 24-7 FYI Addict

    Offline

    From: Stuck in the 50's Welland Ca
    Registered: 4/01/2013
    Posts: 3,980

    Re: 289 breaking valves

    Valve guide not perpendicular to the seat?

    Good work ain't cheap, Cheap work ain't good!   Simple Man
     

    6/19/2019 2:57 PM  #3

    retired 65
    I FYI 24-7

    Offline

    From: nixa, mo.
    Registered: 4/02/2013
    Posts: 336

    Re: 289 breaking valves

    Rudi wrote:

    Valve guide not perpendicular to the seat?

    could be, especially if they put in replaceable valve guides and didn't get everything straight.
     

    "when I drop something, it always goes to center of the car"
     

    6/19/2019 4:31 PM  #4

    TKOPerformance
    Hyper FYIFORD ADDICT

    Offline

    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,523

    Re: 289 breaking valves

    Or didn't get them quite reamed to size...

     

    6/19/2019 7:57 PM  #5

    MS
    Forum Originator

    Offline

    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,297

    Re: 289 breaking valves

    Typically caused by valve springs having excessive seat pressure. Broken stems and broken rockers and ultimately cam failure.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

     

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