Distributor marking versus TDC or 6 degrees? | FerrariChat
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Distributor marking versus TDC or 6 degrees?

Discussion in '308/328' started by Andy 308GTB, Dec 17, 2013.

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  1. Andy 308GTB

    Andy 308GTB F1 Rookie
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    #1 Andy 308GTB, Dec 17, 2013
    Last edited by a moderator: Sep 7, 2017
    The ignition system on my 308 GTB is now ready to be re-installed. It's the single distributor version.

    I've now had a mental crisis in that I can't remember whether the red mark/notch on the distributor (that is aligned with the rotor arm) should be positioned with the flywheel at TDC or 6 degrees BTDC?
    This is killing me as I can't wait to turn the key and fire her up! I'd rather get it right first time... but to my tangled mind both could make sense.

    The picture shows the rotor arm aligned with the red mark/notch - in this position should the flywheel be at TDC or 6 degrees BTDC?
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  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #2 Steve Magnusson, Dec 17, 2013
    It's not that uber-critical. Using either will almost always be fine as it's really just to pick which spline to engage -- which only has a resolution of 30 deg of crankshaft rotation, IIRC, so 6 deg isn't too significant compared to that. If you get it bolted on, and then run out of slot on the dist housing for the operational adjustment just move it over one spline (but the tricky bit is figuring out which way to go ;)).
     
  3. Andy 308GTB

    Andy 308GTB F1 Rookie
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    #3 Andy 308GTB, Dec 17, 2013
    Last edited: Dec 17, 2013
    Thanks for that Steve, experience has taught me that you are always right!

    I will have to mull this one over in my mind as the set up of the distributor advance is such a fine art, I thought 6 degrees would be uber-critical.
    I can kind of see what you are saying as the difference between TDC and 6 degrees BTDC on the flywheel is no more than about 1.5 inches.

    I will engage brain overnight...
     
  4. nerodino

    nerodino Formula 3
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    #4 nerodino, Dec 17, 2013
    Andy, Guess that like me you received a parcel from Berlin today?
    I have just come in from the garage having just reinstalled all my system and it is a lot better.
    However it is still missfiring but now it runs smoother and no longer 'hunting' as it was before.
    I now have everything new apart from leads and extenders (which all tested out ok) So i am going to phone Magnecor tomorrow and get them to send a set of their leads which i think do away with the silly extenders.
    Yes as steve says line it up at either as you wont be far out. But really you need to set up precisely with a strobe.
    Good luck and keep me posted.
    PS Adrian replaced the coils (not fit for purpose!) and the VR amplifiers (both not working 100%) and the pick up sensor leads (two r/h supplied instead of left and right) All supplied by Superformance............Jeez what is this world coming to?????
     
  5. Andy 308GTB

    Andy 308GTB F1 Rookie
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    #5 Andy 308GTB, Dec 17, 2013
    I have a timing gun at my disposal, so on that basis I will press on (hopefully this evening) and let you know how I get on. If all goes well I won't near to go near the ignition for another 30 years!
     
  6. alhbln

    alhbln Formula 3
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    #6 alhbln, Dec 18, 2013
    Misfiring could indicate that the voltage supply to the coils is faulty. As a simple test, wire up a 2.5mm^2 wire to the two coils "plus" terminal (yellow wire from the car wiring) and start the car.

    Let the car idle. If you now encounter misfires, connect the other end of the temporary wire to the battery plus terminal. If this got rid of the misfires, check out fuse holder 'A' in the fusebox and the yellow wire going to the coils.
     
  7. nerodino

    nerodino Formula 3
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    #7 nerodino, Dec 18, 2013
    Ok i will do this tomorrow thanks Adrian
     

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