Eaton 2spd speedometer changer for Columbia

[jimTN]

Sometime in recent years somebody posted an article on using the 2 spd Eaton speedometer changer for a Columbia. Seems to me there was something about switching two gears. Could someone repost that or if they remember reference where it was.

[4dFord/SC]

Don't remember the post, but John Connelly of Columbia Two Speed Parts converted one for me a few years ago.

[jimTN]

I wish I could remember the procedure but what I do remember that it was a swap of existing parts, nothing to buy or machine. It may have been in the EV8 mag. I used one of these in my 34 PU and it seemed to work fine just like it was.

[skidmarks]

I remember a guy on the fordbarn who wrote something about it either here or a ad on ebay. He got kicked off fordbarn but no idea why. Nospartsman was his screen name. I think he sold the truck speedometer changers that were converted.

[4dFord/SC]

It's only a matter of reversing the position of the two gears to convert it from an underdrive to an overdrive unit.

[RobR'35]

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When shifted into regular Ford gears the speed changer should be one to one. When in Columbia gears the speedo gear changer should read faster, about 12 mph faster.
I took one of these apart for a '40-'41 Columbia gear changer. It was a Stewart Warner.
Gears were as follows from input to output.
22 teeth to 18 teeth to 17 teeth 15 teeth

[jimTN]

Thanks all, that make sense.

[RobR'35]

While switching the two gears. Input to output u'll need to turn over the bottom counter gear set too.End for end.
It's because the diameter of the input and output gears are a different diameter. Hope this helps.