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Thread: Help me find the MISS!!!!

  1. #1
    Member MASTER JOURNEYMAN
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    Feb 2004
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    Help me find the MISS!!!!

    We just rebuilt our short block due to a destroyed piston and scarred cylinder. The only change to the engine was boring the block and putting in a 14.2 to 1 set of pistons from a 12.9 to 1 set. Compression is good in all cylinders. Everything else is the same. At idle it sounds like it is hitting on about 5 or 6 of the 8 cylinders. When you bring the revs up it sounds fine. We have checked the plug wires all test good, replaced the dist cap and rotor, 2 different sets of plugs, double checked our valve settings and we don't know where to go next. The ignition is a Msd Digital 6 with an HVC coil and a locked out pro billet dist. Any suggestions on where to look next would be appreciated.
    Just Passin Through!!

  2. #2
    Senior Member RACING JUNKIE fla1976's Avatar
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    Aug 2007
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    1,530

    Noise

    Could be a vacuum leak. You could try spraying some WD40 around the intake and listen for a change in the idle. If it changes temporarily , you have found the leak. It's a little messy but safer than starting fluid.

  3. #3
    Member MASTER JOURNEYMAN
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    Already tried that, no leaks. Thanks
    Just Passin Through!!

  4. #4
    Senior Member RACING JUNKIE
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    Coldwater, MI
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    Re: Help me find the MISS!!!!

    Quote Originally Posted by duswill
    We just rebuilt our short block due to a destroyed piston and scarred cylinder. The only change to the engine was boring the block and putting in a 14.2 to 1 set of pistons from a 12.9 to 1 set. Compression is good in all cylinders. Everything else is the same. At idle it sounds like it is hitting on about 5 or 6 of the 8 cylinders. When you bring the revs up it sounds fine. We have checked the plug wires all test good, replaced the dist cap and rotor, 2 different sets of plugs, double checked our valve settings and we don't know where to go next. The ignition is a Msd Digital 6 with an HVC coil and a locked out pro billet dist. Any suggestions on where to look next would be appreciated.
    Are all the plug firing ? Have you changed plugs out for another set ? Timing isnt way off is it ?
    David Lanning
    IHRA NHRA 387B

    Fleenor Racing Transmission
    419-280-1406
    Lanning Electric
    Complete Drag Car Wiring
    APD Race Engines
    www.apdracing.com

  5. #5
    Senior Member DYNO OPERATOR
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    Aug 2005
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    Rifle Colorado
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    Maybe you have a 4/7 swap cam but have it wired with standard firing order....

  6. #6
    Senior Member RACING JUNKIE
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    Like Hammertime said,I'd put a timing light on all 8 wires and see if they are firing.Any chance of a broken valve spring or that the timing set is off a tooth?I got a chain off one tooth one time in a hurry and it sounded like that
    "The problem with quotes on the Internet is that you cannot confirm their validity"- Abraham Lincoln


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