Idle when timing 70z28 LT1

Discussion in 'Troubleshooting & Diagnosis' started by 70RSZ28CAMARO, Jun 2, 2019.

  1. 70RSZ28CAMARO

    70RSZ28CAMARO Member

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    Hey guys I just want to confirm what the ideal rpm setting should be when I do ignition timing on my car. Is it the recommended spec which I think is 750 RPM or should it be my at my normal idle speed which I have above that. appreciate any help that you can provide
    Thanks
     
  2. dave@ztech

    dave@ztech Veteran Member Lifetime Gold Member

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    If you have vacuum advance, if it is idling too high, the advance may start coming on, I am sure someone with more experience will chime in shortly
     
  3. bourbon_scotch

    bourbon_scotch Veteran Member Lifetime Gold Member

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    It should always be whatever the manufacturer states it is on the tune-up decal in the engine compartment. Those are the numbers tested for that engine. If something has changed on your engine, like maybe you upgraded your distributor from points, those numbers aren't going to mean much.
     
  4. COPO

    COPO Veteran Member Lifetime Gold Member

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    [​IMG]
     
  5. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Is the engine completely factory stock? If so, follow what COPO posted.
     
  6. badazz81z28

    badazz81z28 Veteran Member

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    Yeah, too many things unknown variables here. If it’s an auto, the RPM will drop when you put it in gear. 800 for auto/750 for manual is fine. Honestly even 800 for a manual is fine. There is idle timing and max timing all dictated by the springs in the distributor.

    Is the engine all stock?
     
  7. 70RSZ28CAMARO

    70RSZ28CAMARO Member

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    My setup is the original LT1, 82,000 miles, hooker headers, 2 1/2 exhaust and msd streetfire distributer.
    Thanks
     
  8. 70RSZ28CAMARO

    70RSZ28CAMARO Member

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    One more question, after I timed the engine at 8degrees btdc at 750rpm, I’m noticing an intermittent pop at wot in 3rd or 4th gear. Otherwise it’s running strong. Sounds like unburnt fuel. Maybe timing ? What do you guys think.

    Thanks
     
  9. COPO

    COPO Veteran Member Lifetime Gold Member

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    8* at idle is too low, shoot for 12-14 initial. If you have a back dial light shoot for 36* total with vacuum advance plugged.
     
    70lt1z28 likes this.
  10. 70RSZ28CAMARO

    70RSZ28CAMARO Member

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    I’ll try that, but my mechanic previously had me plug the vacuum canister on the distributer permanently. Does it need to be reinstalled?
     

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