Gearbox rebuild: gears, A or B type

[surf-blue-850]

I'm rebuilding a Magic wand box. But how do I tell if they are A or B type gears?

First off baulk rings are fitted as is a needle roller bearing between the first and third motion shafts.

I understand the angle of the teeth on the gears are different, but they look the same as the cone syncro ones?

Also, as I need new bearings etc are they any brands/suppliers to avoid or any to recommend?

[Andrew1967]

What year is the gearbox ?

A type gears have same cut as the cone box gears.

Can you see the part number stamped on the laygear ?

I have some NOS A type gears / laygear if you need any ?

andrew

[surf-blue-850]

Not sure of the age of the box. Got it to replace the original cone syncro box, as the it needs a laygear.

All the later one needs are bearings and seals etc.

So, if you have parts for a 61 (non-cooper) cone box, might be interested.

[Andrew1967]

Probably got the following for cone box

Input shaft
3rd gear (possibly)
Laygear (probably)
Reverse gear
1st/2nd synchroniser hub (with 1st gear outer ring)
3rd/4th synchroniser (possibly)

All unboxed but NOS

Also got similar for A type baulk ring gearbox

[Andrew1967]

I've also got a genuine BMC NOS third motion shaft double bearing for a cone type box.

They are smaller in diameter to the more common 22G460 bearing.

[Spider]

Not sure if this is any help;-



As Andrew has asked, it seems the quickest way to pick A from B types is from any number stamped on the Laygear.

[surf-blue-850]

Will have a closer look at the laygear and try and find any numbers.

[surf-blue-850]

Number on laygear 22g231

[Andrew1967]

B type gearbox.

I have a few bits for those .

[surf-blue-850]

Think I will mothball the original cone gearbox. Will freshen up the B type with bearings and baulk rings.

[618AOG]

If I remember correctly, non Cooper S A type gears had brass bushes for 2nd/3rd and B type boxes had needle rollers.

[Andrew1967]

Think I will mothball the original cone gearbox. Will freshen up the B type with bearings and baulk rings.

I'd carefully check the teeth on the 1st gear outer track, the laygear 1st/reverse teeth and reverse gear.

If they are chewed up or badly pitted, the gearbox will sound dreadful in 1st and reverse.

[Spider]

If I remember correctly, non Cooper S A type gears had brass bushes for 2nd/3rd and B type boxes had needle rollers.

Yes, Bronze Bushes were part of the original 850 production, but seems it was limited to just that range and they never made it as far as the B type gears;-