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MG MGA - Help! - Positive to Negative - Starter Motor?

Hi guys,

I've converted my MGA to Negative earth and I've just got the engine into my rebuild (2.1 Litre) and the MGB starter that came with the engine wouldn't fit - the solenoid hit the body and the steering column. So I took it off, cleaned my original MGA inertia starter and then thought "b*gger! will this actually work?".

I've looked at Barney's site, and it seems that it will work, but having tried wiring the starter up in a negative vs positive earth style to test it (and then chasing it down my drive as it tried to escape), the motor seems to spin in opposite directions, which surely must impact on the inertia starting bit on the end?

Is there a simple modification I can do?

I'd rather not fork out the extra £160 for a high torque gear reduction starter if at all possible.

Many thanks in advance,

Grant :-)
G Hudson

Grant - First, as you have learned, clamp the starter motor FIRMLY in a vice before testing it - they have an amazing amount of torque that is instanious withthe application of 12 volts. Second, the starter motor doesnt care what polarity it gets, it only rotates in one direction. Third, the later MGB, pre-engaged starter engauges the drive gear in a different direction than the old inertial starters - in other words, the pre-engaged starter pushes the drive gear into the front of flywheel ring gear, while the inertial starter pulls the drive gear into the ring gear from the rear, so the tapered portion of the ring gear teeth are on opposit sides of ring gear. Also, if I remember correctly, the gear tooth spacing are different for the two starters. Cheers - Dave
David DuBois

This thread was discussed on 10/03/2007

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