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Which way does crank move when checking timing?

Discussion in 'Splitty Tech Clinic' started by 68BUS, Oct 16, 2019.

  1. 68BUS

    68BUS Well-Known Member

    Messages:
    4,555
    Location:
    Brisbane
    Hey folks,
    Fairly simple question, but I cannot seem to find any information on it on the web or in my manuals.
    I am getting to the bottom of the programming side of my new Dizzy setup.
    It should replicate a SVDA Dizzy with its curve.
    I have been told by the engine builder that it was built for 7 degree advance based on a 009 dizzy curve.

    I now have it so the timing on idle is showing 7 degrees before Top Dead Centre. Ie, the TDC mark is to the right of the centre of the case.
    When I rev it the crank pully moves anti clockwise, so the TDC mark is to the left of the case. About 10degree at 3000rpm.

    Is this correct?
    I expected the crank to turn further to the right. But I am quickly realising how little I knew about all this before I started.

    Anyone know what their bus does when the strobe light is attached and they rev it?

    Thanks all!!!!

    P.S. I tried to take a video, but it is pretty hard without an extra set of hands. Also the lighting it hard to compete with a timing strobe.
     
  2. grumble

    grumble Well-Known Member

    Messages:
    1,089
    Location:
    Taree
    The engine turns clockwise looking into the engine bay so 7 degrees BTDC will be to the left of the centre of the case and when the engine revs the advance kicks in the mark will move further to the left with the strobe light. If it moves to the right you are in trouble as it is retarding the timing and the vehicle will run like a bag of s..... and overheat.
     
    KahunaKombi, Wayne murray and 68BUS like this.
  3. 68BUS

    68BUS Well-Known Member

    Messages:
    4,555
    Location:
    Brisbane
    So it it turning the correct way and advancing.
    Which is good.
    But it sounds like i have the timing set at 7 degree after TDC to begin with?
    Does that sound correct?

    It would mean the timing curve is correct, but somehow my initial programming is incorrect.
     
  4. tintop

    tintop Well-Known Member

    Messages:
    615
    Location:
    Canberra
    Correct.. You have it set atdc...no good
     
    68BUS likes this.
  5. 68BUS

    68BUS Well-Known Member

    Messages:
    4,555
    Location:
    Brisbane
    Thank you folks. Back to the drawing board for me. Haha.
     
  6. 68BUS

    68BUS Well-Known Member

    Messages:
    4,555
    Location:
    Brisbane
    So after some more programming I have come up with this timing.
    Does this seem correct for a SVDA style advance curve?
    Timing was told to me to suit 7 degree advance.
    Hard to video with the strobe going. But hopefully you can see it.

    Timing @ Idle.



    Timing as the revs go up to 3000rpm.

     
  7. tintop

    tintop Well-Known Member

    Messages:
    615
    Location:
    Canberra
    difficult to see on my crappy phone...but yeah... You start with tdc to the left of the split (7degrees) then it should go another 20 or so to the left
     
    68BUS likes this.
  8. 68BUS

    68BUS Well-Known Member

    Messages:
    4,555
    Location:
    Brisbane
    I must admit, it was not the easiest thing to film. The strobe lighting causes the camera issues. And trying to rev it, the only way I could figure out was using my toe on the throttle plate whilst trying to film it.
    Haha.
     
  9. Alpal

    Alpal Moderator Staff Member

    Messages:
    8,594
    Location:
    Melbourne Bend of Islands
    Need a photo of you taking the photo!
     
    68BUS likes this.
  10. oldman

    oldman Super Moderator Staff Member

    Messages:
    8,910
    Location:
    Avalon Beach NSW
    .....like that clip of changing the fan-belt with a screwdriver......:eek:
    Cheers,
    Mark
     
  11. 68BUS

    68BUS Well-Known Member

    Messages:
    4,555
    Location:
    Brisbane
    Try to avoid changing the fan belt with my toe. Don't think it will work too well.
     
    David H likes this.

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