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365 GT 2 + 2, ignition problem

Discussion in 'Technical Q&A' started by hph1, Jun 28, 2020.

  1. hph1

    hph1 Rookie

    Jun 28, 2020
    5
    #1 hph1, Jun 28, 2020
    Hello everybody,

    The 365 doesn't run the way it should. Cold is fine, when it is warm I have the feeling that a row of cylinders is no longer igniting properly. I strongly suspect it's the ignition. I intend to replace all parts of the ignition. These are the ignition coils, ignition cables, capacitors, breakers. Now I have two parts on the ignition that I don't know what they're for. These are part 'B' and 'C' on the attached pictures. I strongly suspect that they are capacitors for radio interference suppression. Nowhere can I find these parts. What do you think, should I reinstall the old parts or is there a replacement? I can do without radio, I never need it.

    If someone could advise me there I would be very happy.

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  2. wmuno

    wmuno Karting
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    Dec 24, 2007
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    Wilmette, Illinois
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    Bill Muno
    #2 wmuno, Jun 28, 2020
    Each distributor needs a capacitor to prevent the points from arcing when they open. The ones in your photos are not the OEM Marelli capacitors. The Marelli part number is 90071-71 or equivalent. If radio inference is a problem use a resistor spark plug. Try Champion RN-6Y or RN-7Y. The second plug is slightly hotter and helps to reduce fouling at lower RPMs.
     
  3. hph1

    hph1 Rookie

    Jun 28, 2020
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    #3 hph1, Jun 29, 2020
    Many thanks. I did not mention this capacitor, it has part number 95300075. The function of this capacitor is clear to me. It can be seen in the pictures below position 'C'. My question is about the other two capacitors.
     
  4. wmuno

    wmuno Karting
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    #4 wmuno, Jun 29, 2020
    My advice is to remove the two non-OEM capacitors. For radio interference, there are 3 options: electronic filter on the positive lead to the radio; resistor spark plugs; and in-line resistor on the coil to distributor HT wire. On my 330 I use all 3, and they seem to work well with the stock Marelli distibutors. Ignition problems at higher RPMs might be due to a weak coil and/or the advance mechanism not functioning properly. This assumes the timing is set correctly. Find a shop that can test the distibutors on a Sun Distibutor Machine to check the advace mechanism on each one.
     
  5. afwrench

    afwrench Formula Junior

    Nov 24, 2004
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    Mike
    #5 afwrench, Jul 1, 2020
    It is very important to clean all connections and clean the towers on the coils.Arching is common there. I traced a miss some time ago to loose connections on the resistors .Check both coils. Mike
     

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  6. hph1

    hph1 Rookie

    Jun 28, 2020
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    #6 hph1, Jul 1, 2020
    Would it be possible to send me a picture of the ignition of your 330? As you wrote you have only one capaciter between the breakers and the housing (-). The breakers are direct connected to the series/ballast resistor without an other capacitor?
    Thanks for your help.
     
  7. wmuno

    wmuno Karting
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    #7 wmuno, Jul 5, 2020
    I'll try to get you a photo later this week. I have to remove the air cleaner to get access for a photo. Just to be clear, there is one resistor on each coil. The single Marelli capaciter is attached to the side of each distibutor.
     
  8. hph1

    hph1 Rookie

    Jun 28, 2020
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    #8 hph1, Jul 7, 2020
    Thank you very much for your help. I have received various information about the capacitors. I will leave them out. They are not listed in any scheme. You do not have to remove the air filter, this is too much effort. Thanks again.
     
  9. wmuno

    wmuno Karting
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    #9 wmuno, Jul 10, 2020
    Here are 2 photos of the right distributor and coil from my 330 GTC. The positive lead from the ignition switch goes to the coil terminal on back of the coil which is hidden in the photos. The red wire on the other coil terminal goes to the resistor which is mounted on the coil bracket. The black wire on the other side of the resistor goes to the insulated terminal on the side of the distributor. Also on the this terminal is the black wire from the capacitor which is mounted on the side of the distributor. This is the factory wiring configuration for both distributors. Note I have added an in-line resistor (covered with heat shrink tubing ) on the high voltage wire from the coil to the distributor cap.

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  10. hph1

    hph1 Rookie

    Jun 28, 2020
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    #10 hph1, Jul 10, 2020
    Many thanks. I do the wiring exactly the same.
    Have fun with your 330 GTC.
     
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