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Thread: 23d4 distributor clockwise play... normal?

Discuss the Austin Healey Sprite and the MG Midget. Two different but similar cars sometimes referred to collectively as the Spridget.

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    Senior Member matmire's Avatar
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    23d4 distributor clockwise play... normal?

    Is this little bit of clockwise rotation from rest normal? I'm fitting a crane electronic ignition and I'm not sure if I should align the sensor based on where it comes to rest or by holding the cam to its farthest clockwise position.

    1960 Bugeye Sprite - 1275cc
    2016 Mazda MX-5 Miata - club

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    Yoda dklawson's Avatar
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    Re: 23d4 distributor clockwise play... normal?

    When I read your post I thought you were just concerned about the normal advance motion. The video is showing what appears to be backlash in the drive mechanism.

    Yes there is play but I don't know how much is normal or excessive. There are only two places I can imagine that the play is coming from.

    The bottom of the dizzy has a drive dog with approximately 1/8" thick blades that go into the drive gear. Those blades could be worn allowing backlash in the mated dog assembly. The second possibility wear associated with the gear teeth on the cam or drive gear itself.

    Under load I don't think this will cause you any problem since the engine is calling for more and more advance as you accelerate. When you back off the throttle the backlash may leave the spark in a less than perfect place but you won't be under load either so I doubt it will cause you any issue.
    Doug L.
    '64 Morris Mini Cooper-S 1275
    '67 Triumph GT6 Mk1

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    Senior Member matmire's Avatar
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    Re: 23d4 distributor clockwise play... normal?

    so, in that case, do you think I should align the crane sensor to the "rest" position and not the backlashed position.
    1960 Bugeye Sprite - 1275cc
    2016 Mazda MX-5 Miata - club

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    Yoda dklawson's Avatar
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    Re: 23d4 distributor clockwise play... normal?

    I suggest turning the engine in its normal direction of rotation through just under two complete revolutions. Then SLOWLY approach your timing marks, stopping where you want the static timing to be. Turning the engine through its normal direction of rotation without backing up will take up all the slack and backlash in the system.

    While I used the Crane/Alison ignition on our GT6 years ago, it was eventually replaced by a Pertronix unit so I don't remember the nuances of how you set the sensor relative to the interrupter that goes on the dizzy shaft. Others will have to offer advice there.
    Doug L.
    '64 Morris Mini Cooper-S 1275
    '67 Triumph GT6 Mk1

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    Senior Member matmire's Avatar
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    Re: 23d4 distributor clockwise play... normal?

    So, to satisfy my need to investigate this to the fullest, I pulled the distributor drive to check the gears for wear. The drive gear looks good, but it's hard for me to tell if the cam gear is ok. Can anyone with a more trained eye tell me what they think of it?



    1960 Bugeye Sprite - 1275cc
    2016 Mazda MX-5 Miata - club

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