BAE 202B Ignition coil specifications | FerrariChat

BAE 202B Ignition coil specifications

Discussion in 'Technical Q&A' started by Piston.Broke, May 14, 2021.

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  1. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
    51
    Australia
    Full Name:
    Rick
    Hi everyone,

    Does anyone have the specs for the Resistance values (Primary and Secondary windings) to check the Magnetti Marelli BAE202B Ignition coil (As used on many of the earlier Ferrari's).

    Thanks for your assistance.

    Cheers!

    Piston.Broke
     
  2. raemin

    raemin Formula 3

    Jan 16, 2007
    1,825
    Lyon (FR)
    Full Name:
    R. Emin
    The resistance is quite common (1.5ohm?), the problem lies on the fact that this coils has two separate (-) : one for the ground and one for "breaking" the magnetic field. If you decide to use a dinoplex together with a regular coil with one single (-) post, you will send huge back EMF spikes to the ground of your car. Not sure what's the actual risk involved, but best case scenario: the lead acid battery will not like it, and god knows what for a worst case.

    I would be personally be afraid to damage whatever electronic is in the car: audio, speedo, cellphone charger.
     
  3. raemin

    raemin Formula 3

    Jan 16, 2007
    1,825
    Lyon (FR)
    Full Name:
    R. Emin
    Roughly speaking, the Dinoplex was an early implementation of CDI. It does break the magnetic field just like the old-school points (i.e break the negative side of the winding). This was Ok for the point systems that did use reasonable voltage, but not appropriate for the CDI higher votage. the solution was to use two separate (-) for primary and secondary windings. Later systems (GM HEI) are breaking the (+) side of the winding which does not require separate posts on the coil.

    If you manage to get a coil modified so as to separate the (-) of the primary and secondary windings, just let us know!
     
  4. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
    51
    Australia
    Full Name:
    Rick
    HI raemin, thanks for the reply.
    I dont want to replace the coil as yet, I just want to electrically test it to see if it still within spec.
    I need to know the electrical resistance specs of the original coil so that I can check that it is OK. (My car seems to have a relatively loww energy spark).
    I have searched online and can't find the actual resistance values for the coil. (Ferrari 400i).

    Cheers!

    Piston.Broke
     
  5. raemin

    raemin Formula 3

    Jan 16, 2007
    1,825
    Lyon (FR)
    Full Name:
    R. Emin
    The orignal recommended plugs are quote cold (equivalent to ngk BP8ES), some are using hotter plugs such as BP6ES that are more approproate to relax driving.
     
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  6. wmuno

    wmuno Formula Junior
    Silver Subscribed

    Dec 24, 2007
    430
    Wilmette, Illinois
    Full Name:
    Bill Muno
    I had the Marelli coils from a 1967 330 out for repainting and new stickers. I measured the primary resistance as 1.3 ohms; the external resistor was also 1.3 ohms. The seconary resistance was 6300 ohms. However, I believe these are the 201 coils.
     
  7. raemin

    raemin Formula 3

    Jan 16, 2007
    1,825
    Lyon (FR)
    Full Name:
    R. Emin
    Older coils could easily ne replaced by a bosch red coil, these 202 do not have substitite that I am aware of.

    To answer @Piston.Broke question, you may have a look at dinoplex.org, a'd eventually ask there for the detailed specifocations. The webmaster is a FChat memeber.
     
  8. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
    51
    Australia
    Full Name:
    Rick
    Thanks for the infor wmuno and raemin. I will try to find out the infor from dinoplex.org. I am aware of the threads covering replacement of the original ignition systems with the MSD 6AL2 (6142) but I will try and keep the originality if possible. At this stage, I would like to check the coil as the spark seems to be weak.

    Cheers!

    Piston.Broke
     
  9. raemin

    raemin Formula 3

    Jan 16, 2007
    1,825
    Lyon (FR)
    Full Name:
    R. Emin
    No mater what the spark will be weak: the single coil has to drive 12 cylinders at 6200rpm. In order not to deplete this single coil at such frequency we have to rely on small spark plug gaps (i.e small sparks), which combined with cold spark plugs could lead to a few misfire at idle. The V12the engine is so smooth that it could still idle with misfires on half cylinders...

    If the not so perfect idle is an annoyance just go for slightly hotter plugs. The consensus is that the stock champions were really on the cool side, going one index higher (ex: NGK BP7ES) is a good compromise, and even an additional index (BP6ES) if your car never reaches 200km/h. If your car is not overly rich you could try thin tip plugs (iridium or platinum) for a better idle. I personally avoid hot plugs because the head is very thin and I prefer to keep it as cool as I can.
     
  10. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
    51
    Australia
    Full Name:
    Rick
    This is great advice, thanks raemin. I need to check the ignition system and I intend to replace the plugs also. I was thinking of using the NGK BP6ES.

    Cheers!

    Piston.Broke
     
  11. Piston.Broke

    Piston.Broke Karting

    Mar 5, 2009
    51
    Australia
    Full Name:
    Rick
    Hi everyone,

    Adrian Le Hanne (A mine of information on the Magnetti Marelli Ignition systems) advised the following information, for those who need to run a test on the Magneti Marelli BAE 202B Ignition coil:

    Coil specification:

    When measured with a Multimeter, the primary resistance should be 0.9 to 1.2Ω and the secondary resistance should be 5.2 to 5.4kΩ.

    Primary inductance is 3.5mH @1KHz, secondary inductance 40H @1KHz, winding relation is 1:75. The BAE 202B has three terminals input due to the different internal wiring, unfortunately it cannot be replaced with any other coil.

    Weak spark:

    A weak spark might indicate a failure of the AEC104 transformer or the two transistors. If the AEC104 or the BAE202B turns out to be unserviceable, the most economic replacement is a MSD 6AL-2 and Blaster 8200 coil. The AEC104A housing can also be rebuild with the MSD 6AL-2 internals. (As per the thread).

    I hope this will be of assistance to anyone wanting/needing to check the OEM ignition system and thanks Adrian, so very much for the great info!

    Cheers!

    Piston.Broke
     
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