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Thread: Timing advance

  1. #26




    slammedR/T's Avatar
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    Quote Originally Posted by grapejuice1998 View Post
    A 7 yr old timing chain could put a variable in your valve timing.
    FIXED
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    Quote Originally Posted by slammedR/T View Post
    FIXED
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  3. #28


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    Quote Originally Posted by Five9Dak View Post
    We don't have any evidence that the method you are using to record timing is accurate.

    Verify it against a timing light or we're just pissing in the wind.
    It's the reading from the Torque app meaning, it should be exactly what the PCM is putting out, but I can't say for sure either. Can anyone verify that the torque app timing advance reading is accurate?


  4. #29



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    Quote Originally Posted by skunkxracing View Post
    No, timing is based solely on crank position and timed from the PCM.
    If the crank position sensor reads a window in the flexplate and sends the signal to the pcm to fire, what happens if the distributor itself sends a late spark due to a stretched chain?
    Alan Short
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    Quote Originally Posted by grapejuice1998 View Post
    If the crank position sensor reads a window in the flexplate and sends the signal to the pcm to fire, what happens if the distributor itself sends a late spark due to a stretched chain?
    Do explain how perceive it will be late?
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  6. #31


    Blown and Squirted

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    The only consequence of a stretched timing chain on spark ignition timing is the rotor phasing will be different. The spark will occur at the commanded time.

    Crank sensors/flexplate window misalignment will cause timing to be different than anticipated. Back in the day people moved their crank sensors to change the timing globally.

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  7. #32



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    Thinking more about it; the distance between the pullies never changes, so as long as the chain is taunt under load, the rotor will more or less be where it is with a new chain. I have seen wild fluctuation at idle with a stretched chain, but it becomes consistent if you give it steady rpms. I mistakenly applied that logic to total timing and learned something in the process.

    My mistake! As you were!
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    Your logic wasn't necessarily flawed if we were talking traditional dizzys that control timing. Their relationship to tdc will be influenced by a worn chain.
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  9. #34




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    Quote Originally Posted by grapejuice1998 View Post
    Thinking more about it; the distance between the pullies never changes, so as long as the chain is taunt under load, the rotor will more or less be where it is with a new chain. I have seen wild fluctuation at idle with a stretched chain, but it becomes consistent if you give it steady rpms. I mistakenly applied that logic to total timing and learned something in the process.

    My mistake! As you were!
    Stretched chain will also cause late valve timing even when taunt under WOT in the range of 4* and I have seen up to 10* of valve timing retard from a stretched chain. But like Skunk and Chris said, it will only affect distributor phasing and not ignition timing as it is computer controlled.
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    The guys on the Ram forums say swapping to a real chain makes a huge difference. Those guys aren't really into mods, so they do one thing at a time as in "Maintenance".

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  11. #36


    Blown and Squirted

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    I definitely noticed after I replaced my worn timing chain. I doubt it's the cause of your miss though.

    '99 R/T- MSIIextra fuel/spark/idle, ZCP mx422 supercharged, ZCP Tbrake 727, PPC 10" 3800, 4.10, (\/) Headers, 2.5" Duals, Truetrac, Boyd Timeless 6's, Hotchkis TVS.
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  12. #37



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    Quote Originally Posted by Five9Dak View Post
    I definitely noticed after I replaced my worn timing chain. I doubt it's the cause of your miss though.
    I don't either...

    My miss is all part of the Socialist EFI.
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