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Need igniton timing help fast!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by weisel, Apr 23, 2002.

  1. weisel

    weisel 1/2 ton status

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    I am trying to time my 350 in my 77. I set the idle at 700 like it says to, and pulled and plugged the vac advance, and hooked up the timing light. Well, it woun't run at 8 degrees BTDC. It only runs way advanced. Like about 30 BTDC. Whats going on. I need to get this thing going soon. Also, I was runnng it at around 30 BTDC for a while, but at that advance I can't get the carb adjusted and it runs like crap all the time.
     
  2. POWERMAD

    POWERMAD 1/2 ton status

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    It sounds like the mechanical advance is stuck.
    Pull the cap off and twist the rotor, it should snap back.
    if not then you will have to pull the distributor out and tear it down to free it up.
    Just remove the weights and springs and knock out the roll pin on the gear.
    Then pull out the shaft and clean it all up real good.
    good time as any to drop in a new set of springs and weights also.
    This is a common problem and easily fixed.
     
  3. weisel

    weisel 1/2 ton status

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    I don't think that has happened because I just freed it up like you said about 3 weeks ago. But to make sure, I will go check right now. But on another note, I was on 1986Blazer's page and he had the same problem. But his was that the timing marks on the balancer was set up to be in a dfferent positon than the marks on the timing cover. This could also cause the same thing. I will go check both right now and get back with an update.
     
  4. weisel

    weisel 1/2 ton status

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    Ok, neither of those are the problem. The mchanical advance is working, and I used a positive stop tool to find true TDC and it proved that the harmonic balancer and the timing marks are correct in relation to eachother. Anyone with ideas please help!!! I can't think of anything else.
     
  5. MOABDADC22

    MOABDADC22 1/2 ton status

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    My timing light has the little knob that you gan advance the light with.....maybe yours is set at 30 degrees? Are you sure you have the timing light on the correct plaug wire? Have you pulled the distributer lately?? It is possible to put the distributer in one tooth off and compensate for this by changing the location of the plug wires?

    My guess is that the distributer is one tooth off, since you are consistently off by 30 degrees.

    Just a thought....maybe I am way off the mark..Good luck.
     
  6. weisel

    weisel 1/2 ton status

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    I just pulled the distributor when I swapped the engine. I don't think it would be off one tooth, but I'll keep it in mind as a back up. I just checked the fireing order as a lame attempt to make sure everything is hooked up right, and they were correct. I never heard of a knob on the timing light. I will go check right now. I am hooking it onto plug wire #1, the driverside front cylinder. Be right back.
     
  7. weisel

    weisel 1/2 ton status

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    Ok, no little knob. Any more ideas?
     
  8. TopOff

    TopOff 1/2 ton status

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    Are you running HEI or points?
    I thought 77 has HEI.
    Still, hard to imagine, idle at 30 degrees BTDC.
    I would say double check the timing marks on the balancer.
    Has the balancer been changed?
    Good luck
     
  9. weisel

    weisel 1/2 ton status

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    Thank you everyone for your quick responses. Turns out the dang timing light was giving incorrect readings. I found an inductive type of one and timed it. The one I was using first was the type that connects between the plugwire and the plug. Don't know why it was wrong, just know that I will buy the inductive type next time. Thanks again.
     
  10. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    So what did your timing end up being?
     
  11. weisel

    weisel 1/2 ton status

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    I timed it with the inductive type to 8 BTDC, then hooked up the other light and it showed to be far to the pass side of the scale (my guess would be 20 BTDC). And I still don't know why it would show to be MORE advanced than the inductive type.

    Adjusted the carb and she perrs like a kitten now for the first time ever exept when I first got the truck a year ago.

    Still need to get some more work on it. Found out that the carb. thottle bushing is worn and moving the primary throttle likage up and down causes changes in the idle speed. It seems to be moving about .010 from fully up to fully down. I was told of a place that will put new bushings in it for $20, so I think that is what I will do.
     

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