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Thread: Ring and Pinion

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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    Jedi Hopeful histerical's Avatar
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    Ring and Pinion

    I pulled the drivetrain ( 1275 w/ Datsun) to paint the motor ( the one thing I skipped when I restored the BE 8 years ago), to replace the water pump, and rebuild the tranny. This is what I found. No wonder the starter would often not engage. I bought a new ring gear and starter pinion from Moss and noticed on the pinion box that it said " 10 teeth". I counted the ones on the old pinion and there were 9. The starter came from VB, I recall, and I don't understand why it was wrong. The teeth count on the new ring gear matched the old one ( also from VB I think). Replacing the pinion on the starter is a bit of a chore but doable.
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    Re: Ring and Pinion

    I remember reading or being told that going to a 10t pinion was to increase the engine speed when starting [spins it faster]
    Russ

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    Jedi Hopeful histerical's Avatar
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    Re: Ring and Pinion

    I always thought that gears were indexed or pitch-matched and changing the tooth count on one required a corresponding change to the other and were used in sets. A 9-tooth gear could not have the same pitch or spacing as a 10-tooth one of the same diameter. Of course I could be wrong once again....

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    Re: Ring and Pinion

    How can both of these mate with the same ring teeth ?
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    Darth Vader Rut's Avatar
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    Re: Ring and Pinion

    Since the ring gear and starter pinion are only engaged briefly during the starting process I don't think it matters as long as the teeth allow engagement. This is not like a matched gear set we commonly worry about shimming and measuring. Put that thing together and crank her up!
    Rut
    Rut, '60 Bugeye, '70 MGB, '62 TR4, '66 TR4a IRS, '67 TR4a IRS, '68 TR4a IRS, '72 TR6

    When I went to school, they asked me what I wanted to be when I grew up. I wrote down 'happy'. They told me I didn't understand the assignment, and I told them they didn't understand life. John Lennon


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    Jedi Hopeful histerical's Avatar
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    Re: Ring and Pinion

    You betcha. Going back in tomorrow.

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    Jedi Trainee Joe Schlosser's Avatar
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    Re: Ring and Pinion

    Roll the pinion gear through the ring gear. It should move smoothly with the teeth engaging completely as it moves along. There should never be any misalignment of the teeth
    Joe Schlosser
    SCCA National License, Retired
    60 Bugeye, since 1966
    SCCA FP, sold but not forgotten

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    Re: Ring and Pinion

    I just think it is odd that Moss sells the ring gear for the 1275 and two pinions ( depends on the starter#) that both have 10 teeth and I had a starter with a 9-tooth pinion, which was quite chewed up along with the ring gear.

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    Jedi Trainee Joe Schlosser's Avatar
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    Re: Ring and Pinion

    just took a look at my collection of starters. 1 at 10 teeth, 4 at 9 teeth. I cannot tell which engine sizes they came from. a mix form all three sprite engines
    Joe Schlosser
    SCCA National License, Retired
    60 Bugeye, since 1966
    SCCA FP, sold but not forgotten

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