Ignition timing 1969 365 GT | FerrariChat

Ignition timing 1969 365 GT

Discussion in 'Vintage (thru 365 GTC4)' started by Waltf, Nov 4, 2014.

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  1. Waltf

    Waltf Rookie

    Apr 9, 2014
    12
    #1 Waltf, Nov 4, 2014
    I'm in the process of performing a tune up on my car. I set the ignition points gap according to the owners/operating manual but I 'm unable to find any timing marks on either the flywheel or belt pull. I can see the flywheel through the window at the top of the bell housing. I rotated the flywheel 360 degrees and no marks of any kind were visible. Are the timing marks on another component?
     
  2. dgrperformance

    dgrperformance Formula Junior

    Feb 28, 2005
    311
    Oceanside, CA
    #2 dgrperformance, Nov 4, 2014
    Timing on the 245 motor(365 single cam) it actually intended to be set from under the car and that access window. There is a mark on the flywheel for TDC at PM 1/6 and the actual timing mark at AF/10 which is 10° advance. There is also a mark for PM 7/12 and AF/10 Mark for the second bank. If you have a US car the dustributors should be set up to retard on the R1 points and than advance to the R2 points with the throttle actuated microswitch at 1600-1800 RPMs.

    That being said, if you don't have a lift you can time the car from the top at the access window on top by hooking the timing light to the 3/9 cylinders which will give you the same result.

    Zac
     
  3. Waltf

    Waltf Rookie

    Apr 9, 2014
    12
    #3 Waltf, Nov 5, 2014
    Thank you Zac. Very helpful, I will give it a try.
     
  4. Dogdish

    Dogdish Formula Junior

    Dec 27, 2005
    367
    Denver
    #4 Dogdish, Nov 5, 2014
    You may have to get a really bright light down there. The marks are most likely there, they aren't very prominent. Take your time. I put some different colored dots for the two different AF/10 marks. I also had a notebook with a drawing of my flywheel to remember what marks were where. They will show up much easier for the timing light.

    Mine was not US spec, so each set of points just did 3 spark plugs, not the retard/normal ignition timing for emissions that Zac mentioned.

    Bill
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    34,119
    Austin TX
    Full Name:
    Brian Crall
    #5 Rifledriver, Nov 5, 2014
    By this point many cars have had flywheel replacements with either no marks or marks for whatever model flywheel they were able to source. I have had to start from PMS 1/6 measured on the piston and work from there making my own marks on more than one car.
     
  6. Waltf

    Waltf Rookie

    Apr 9, 2014
    12
    #6 Waltf, Nov 8, 2014
    The timing marks were very faint, but I was able to locate them once I knew where to look. I checked the timing for cylinder 3 through the top window in the bell housing and it appears to be set to the AF10 for PM 7/12. The timing for cylinder 9 looks to be about 60 degrees behind the PM 7/12 mark. Is that even possible? I double checked the ignition leads to make sure I was connecting the timing light to the right leads. Given the 60 degree difference I also checked the timing using cylinders 5 and 11 and in this case both were timed to their respective AF10 marks. The car idles and accelerates smoothly. The only issue I'm having is tail pipe backfire on engine deceleration which I believe is consistent with the retarded timing. Setting ignition timing is usually pretty straight forward, I can't understand what I'm doing wrong. Any advise would be greatly appreciated.
     
  7. DWR46

    DWR46 Formula 3
    Honorary

    Jun 19, 2012
    1,847
    #7 DWR46, Nov 8, 2014
    Walt:

    1. Is there a "pointer" or indicator mark in the top window as there is under the car? You want to be sure you are timed exactly on the AF10 marks for each bank, not just within the window.

    2, As to the tail pipe backfire. Try richening the idle mixture screws 1/8 turn and see if that helps the problem.
     

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