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Timing Chain ?'s

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Leinie, Dec 4, 2001.

  1. Leinie

    Leinie Registered Member

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    Timing Chain ?\'s

    I just reinstalled my 350 with fresh heads. I had overtightened the valves and ran it for half an hour ( on and off ) nerver really revved it much. Could this make the timing chain jump a tooth?After readjusting the valves It runs well at idle and off the line but falls flat about 2200 rpm.
    The Shortblock has about 10k on it, double roller timing set was new with rebuild. New harmonic balancer, new edelbrock performer& 600cfm carb. HEI with new plugs and wires.
    Is there a way to check the timing gears without removing the pan and front cover?
    Thanks for any help

    72 K5 CST X 2
     
  2. 69K5

    69K5 1/2 ton status

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    Re: Timing Chain ?\'s

    I'm not sure, but i'm pretty certain that if the timing chain jumped it would have trouble at idle too. there isnt a way to check it that i know of without taking it all apart.could've stacked a valve.
     
  3. ErikH

    ErikH 1/2 ton status

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    Re: Timing Chain ?\'s

    I'd guess your secondary metering jets are clogged or your timing is off. I can't imagine the timing chain jumping teeth, but maybe someone else has seen this. Maybe a few of your lifters have been damaged and they're not pushing the valves fully open... this is a wild guess.
     
  4. 71RestoRod

    71RestoRod 1/2 ton status

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    Re: Timing Chain ?\'s

    Try hooking up a vacuum gauge. If your vacuum is less than 10 in. Hg you might have a valve timing problem... but more than likely a vacuum leak. With a stock or mild cam you should be pulling at least 18 in. Hg. Less than 18 might mean an ignition timing problem. The needle should be fairly steady... If it floats slowly from low to high and back check your carb. If it bounces around a lot, call a doctor.
     
  5. chevyracing

    chevyracing 1/2 ton status

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    Re: Timing Chain ?\'s

    No.

    John

    Like to go sloppin' 'round in da mud in a rapid fashion....=)

    <a target="_blank" href=http://coloradok5.com/gallery/albun31?&page=1>BLAZER PICS</a>
     
  6. Steve_Chin

    Steve_Chin 1/2 ton status

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    Re: Timing Chain ?\'s

    Highly doubtful that the timing chain slipped a cog.

    The only way to check whether the cam timing is off is to put a degree wheel on the engine and compare the 0.050" specs against the cam card.

    FWIW, if the cam is retarded a tooth, you'd have a really lousy idle and it'd continue to pull in the rev band (although not well).
     
  7. Leinie

    Leinie Registered Member

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    Re: Timing Chain ?\'s

    Thanks all,
    I'm feeling better about this problem and will start looking into other areas.

    72 K5 CST X 2
     

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