Emergency Question: Broken Valve Locks
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2004-2007 Cadillac CTS-V General Discussion Discussion, Emergency Question: Broken Valve Locks in Cadillac CTS-V Series Forum - 2004 - 2007; During my cam installation, I reused the original valve locks with new springs, seats, seals, and retainers. Upon starting the ...
  1. #1
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Emergency Question: Broken Valve Locks

    During my cam installation, I reused the original valve locks with new springs, seats, seals, and retainers. Upon starting the engine up, I heard a clicking sound that I only just identified. After tearing down the entire valvetrain, I found that one of the two locks on the #8 cylinder intake valve stem were missing, and the other was cracked in half and just barely hanging on.

    Obviously, I'm relieved that I caught the problem in the nick of time, but this is my daily driver and none of the shops in my area have replacement locks in stock.

    Question #1:

    During the diagnosis of the problem, I also found that my #6 cylinder was not providing power by disconnecting and reconnecting the ignition coil attached to the #6 spark plug. Is it possible that the missing valve lock half somehow got into that cylinder or jammed the lifter? There's a lot of space behind the top of the heads that the lock could be hiding in, but short of removing the heads, I won't know.

    Question #2:

    I've identified that Comp Cams #623-16 is the correct lock for my LS2 application. While I'm at it, do you think it's worthwhile to replace all of the locks in the valvetrain? I think that this might've been an isolated incident due to installer (namely, me) error in setting these locks in the retainer, but maybe this is something that happens with stiffer springs (in this case, Comp 26926 with 470 lbs open seat pressure).

    EDIT / Question #3:

    Ordered 16 new Comp cams locks. In the meantime, do you think I should be taking off that head to ensure that there's nothing down there? I did a visual inspection with a flashlight--even peered down the pushrod holes--but couldn't spot anything.

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  3. #2
    darkman's Avatar
    darkman is offline Cadillac Owners Master
    Automobile(s): 2005 CTS-V
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    Re: Emergency Question: Broken Valve Locks

    I doubt that the valve lock would make its ways into the cylinder. I base this on the fact lots of folks report having the rockers lose their needle bearings and I don't recall any cases on them finding their way into the cylinder. Those needle bearings that are not found under the valve cover tend to be found in the oil pan. If they do not come with the oll they can be coaxed out with a strong magnet on the oil pan.

    If you want to check the cylinders you might try to find one of those camera tools used to look inside things.
    http://www.amazon.com/ProVision-PV10.../dp/B00002255Q

  4. #3
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Re: Emergency Question: Broken Valve Locks

    Quote Originally Posted by darkman View Post
    I doubt that the valve lock would make its ways into the cylinder. I base this on the fact lots of folks report having the rockers lose their needle bearings and I don't recall any cases on them finding their way into the cylinder. Those needle bearings that are not found under the valve cover tend to be found in the oil pan. If they do not come with the oll they can be coaxed out with a strong magnet on the oil pan.

    If you want to check the cylinders you might try to find one of those camera tools used to look inside things.
    http://www.amazon.com/ProVision-PV10.../dp/B00002255Q
    Thanks for setting my mind a little more at ease. Over on the LS1Tech forums, SuperSlow suggested I put a pen magnet down the pushrod holes to see if the lock got caught in the lifter trays. If I can find one that'll fit, I'll give it a shot.

  5. #4
    FuzzyLogic is offline Cadillac Owners Connoisseur
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    Re: Emergency Question: Broken Valve Locks

    Thanks for your help, guys. The broken valve lock was the source of the ticking issue. I replaced all valve spring locks with Comp Cams 623-16 hardened valve locks. The dead #6 cylinder was due to me over-torquing that spark plug. I replaced that spark plug with a fresh NGK TR5IX (same as the others). The car sounds great, and is due to be re-tuned by Jannetty Racing on Monday. I'll follow up then.

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