SM805A distributor VR sensor change | FerrariChat
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SM805A distributor VR sensor change

Discussion in '308/328' started by sbstn, Dec 5, 2016.

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  1. sbstn

    sbstn Rookie

    Sep 6, 2013
    13
    Netherlands
    Full Name:
    Sebastian
    #1 sbstn, Dec 5, 2016
    Having removed the single electronic distributor (Marelli SM805A) from my '79 Euro GTS for replacing the the faulty VR sensors, I'm now faced with the problem how to remove the top plate to access the mounting for the sensors.

    In an earlier thread (https://www.ferrarichat.com/forum/308-328-sponsored-yellow-compass-group/435679-rebuilding-308-electronic-ignition-sm805a-distributor-marelli-aei200-ignition.html), Adrian advised to tap the distributor axle gently on the top/rotor side to pop it out.

    Do I have to do anything regarding the upper distributor bearing (the one in the top mounting plate under the rotor)? Does tapping the axle remove it from the inner race, or does the outer race pop out from the mounting plate? I'm a bit lost since I could not find any overhaul manual for this type of distributor.


    By the way, does anyone know a source for the heat sinks on which the HEI modules and coils are mounted? I found out yesterday that only the upper coil and module are mounted on a heat sink, the lower coil and module hangs on some kind of standoffs and I assume that this might have also led to that HEI module overheating. Based on measurements taken from the existing heat sink, I'm whipping up a replacement with SolidWorks tonight and would get it CNC milled from an aluminium billet (6061 or 6063) by a rapid prototyping shop, if no replacments are available anymore.


    Thanks,
    Sebastian
     
  2. sbstn

    sbstn Rookie

    Sep 6, 2013
    13
    Netherlands
    Full Name:
    Sebastian
    #2 sbstn, Dec 5, 2016
    Last edited by a moderator: Sep 7, 2017
  3. Andy 308GTB

    Andy 308GTB F1 Rookie
    Lifetime Rossa

    Jun 2, 2004
    2,660
    Essex, UK
    Full Name:
    Andy M
    #3 Andy 308GTB, Dec 5, 2016
    Last edited by a moderator: Sep 7, 2017
    Mine were looking a little tatty too, when I pulled them a few years back!
    Apart from a little stumble at higher revs, the car ran fine like this...
    Image Unavailable, Please Login
     
  4. Andy 308GTB

    Andy 308GTB F1 Rookie
    Lifetime Rossa

    Jun 2, 2004
    2,660
    Essex, UK
    Full Name:
    Andy M
    #4 Andy 308GTB, Dec 5, 2016
    I don't recall any particular problems separating the various bits once the screws had been removed. I may have used a bearing puller or similar but it was a few years ago.

    I can only suggest the likes of Eurospares or other breakers for the heat sink. I guess even owners who have switched to more modern ignition systems will have utilised the heat sinks, so your best bet will be where cars are parted out.

    Good Luck
     

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