365 GTC/4 ignition wiring replacement

Discussion in 'Vintage (thru 365 GTC4)' started by Bryan, Nov 10, 2003.

  1. Bryan

    Bryan Formula 3

    I replaced the ignition wiring in my 365 GTC/4 this weekend and thought the following might be of interest.

    Magnecor 7mm ElectroSport wiring.
    Telephone (USA): 248-471-9505
    Fax (USA): 248-471-9506

    Ask for Frank. A bit abrupt (he had a busy day), but he sent me exactly what I needed. He does need to know the length of the wires, as they don't have an off-the-shelf set for a C4. If you order a set, add an extra inch (see below). See the online catalog for measuring instructions.

    $160 for 14 cables. Custom cut lengths set.
    12 with extended reach straight-in spark plug boot at one end and raw wire at other end. 2 with ignition coil connector at one end and raw wire at other end.

    Photos at

    Comments in no particular order.

    The Ferrari 7mm original wiring is slightly larger than the Magnecor 7mm wire. I could not find my micrometer, so I don't know the exact diameter of either. Eyeball measuring with a metric ruler indicates that the Magnecor are exactly 7mm, the OEM are 7-7.5 mm (Swelling over time perhaps?), and the holes in the cap are a touch over 8 mm in diameter. The ElectroSports 8 mm might fit, but I can't say for sure. Magnecor also makes an 8.5 and a 10 mm product line, both are for racing applications. I don't think the 8.5 mm will fit the cap.

    The design of the wire connection to the distributor cap uses a brass screw to puncture the wire to make the connection. You have to check continuity to ensure that the new wires make good contact with the screw. Cutting an inch off the raw end of the wire helped.

    I also checked the continuity on the original wiring. Some of the wires seemed to exhibit poor connectivity and this may be the reason for my hard starting. (My starter motor appears to be OK..see thread on 365 GTC/4 Starter Motor Removal)

    Each wire has TWO numbered labels. One label at the spark plug end indicates the cylinder. The number at the other end indicates the terminal in the distributor cap for correct connection. The cylinder numbers (1-12) do not match the distributor cap numbers, which are 1-6 on each cap. This must all be setup correctly to ensure firing order is correct.

    OEM wiring has a white polymeric sheath over the cables. There was too much friction to get these off the longer wires, so I didn't put these on the Magnecor wiring. Does anyone know what this sheath is for...heat dissipation?

    Of course, the proof will be what happens when I get the starter motor back in and turn the key!!
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  3. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner

    Dec 1, 2000
    Southlake, TX
    Full Name:
    Rob Lay
    Thank you very much for the documentation. Keep them coming everyone! Document everything you do and if everyone does that, then we have a huge archives we can easily search on.

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