Gearboxes

[les]

I have two gearboxes that I rebuilt a few years ago but have forgotten some details. I remember one has the number something 299 ? on the shaft from the bell housing, MG gearbox? The other I feel is a standard 1098 gearbox. How do the ratios of the possible MG box suit the Minor and would it suit the speedo. I’ll probably use the standard one anyway but would like some info. The gearbox
Installed, on the odd occasion will resist moving from third to fourth without fiddling about, so I might have to use one of the above boxes. I hope not though !!!

[Bill_qaz]

The output shaft speed would be the same versus road speed as it's the diff ratio. If the speedo drive pinion ratio that the ruling factor, count the revolution of speedo drive to revolutions of out put on both gearboxes.
A different 3rd gear as example would only effect engine rpm to vehicle speed.

[les]

Thanks for that Bill, I’ll do that check.

[philthehill]

Les
I have used 948cc, 1098cc and 1275cc gearboxes in my Minor and found very little difference in everyday use between the Minor and MG gearboxes. The only real difference is that as the engines got bigger the gearboxes got stronger.
12G229 is the gearbox fitted to the 1275cc Midget/Sprite.
The speedo drive may have to be changed dependent upon the diff ratio.
Here is the data chart for 'A' Series gearboxes:-

gearbox data 1.jpg (105.09 KiB) Viewed 133 times

[les]

Ah, that’s really handy Phil.