3 Synchro gearbox 1st gear mesh

[monte chris]

Hi,

I have just recently finished putting together my first gearbox, 3 synchro 22A1288 case with Minispare SCCR gear set, NOS synchro hubs and original 22g202 reverse gear. All spins nice and freely and changes gear with issue, however when I select 1st, it feels like the teeth aren't meshing correctly for what appears to be 1/4 of the laygear rotation. When I mark the teeth where I feel the issue, next time the come around and mess together, the problem appears to of moved to different teeth.

When I select reverse, it feels like none of the gears are meshing correctly on 1st gear. The laygear does seem to rotate freely when selector is put into 'mid-position'. Checking 1st gear, it does have the undercut between the teeth, so I'm a little lost of where the issue is.

Any help or advice would be much appreciated before I start taking the gearbox apart.

Cheers

Chris

[ricardo]

That would be expected if you had an A type first synchro hub and a B type laygear / reverse. However, I have no idea of what is that Minispare SCCR gear set. I would ask minispares giving all the part numbers you have bought and fitted in the box, they should be able to tell you if that set would work or not. Perhaps you have bought a first synchro for a midget?

[goff]

As said by Ricardo , Contact Rich at minispares north , he will be helpfull , best by email.

[monte chris]

Thanks for the advice and help.

Just been back up to shed and just wonder if any of you with more knowledge on the different types of gear could confirm that 1st gear is 'B' type before I contact Minispares.

Cheers

Chris

[Andrew1967]

Is it a MiniSpares 1st gear hub or a genuine NOS hub assembly Chris ?

My initial thoughts are that the 1st gear teeth look a little ‘fat’ and could be A type

[monte chris]

Its a genuine NOS 1st gear, on a 22g250 if that makes any difference.

[swifty]

The first gear does look as if it's got the undercut

[ricardo]

Show us the first synchro hub from the top, please. The 250 is just the inner hub, doesn't matter in this case.

[monte chris]

There does seem to be definite undercut on the gears, but here is a picture from the top. I tried to get at least one tooth square on with the camera.

[ricardo]

That's an A type synchro hub.

[iain1967s]

This is the 32 tooth B type:
http://www.minispares.com/product/Class ... A1021.aspx

[monte chris]

Thanks for the help chaps.

Just out of interest, how is the best way to tell if it as 'A' or a 'B' type?


Cheers

[Andrew1967]

Have a look at Swifty's post with the two gears side by side.

Subtle differences to the shape of the teeth (A type teeth are a little fatter) and also the B type has the teeth 'troughs' slightly undercut.

NOS A type gears are much easier to find than B type, but are easily confused.

Unfortunately BMC didn't bother to stamp the outer gears with a part number very often and as Ricardo has said, the inner hub can be used on either I believe.

[1071bob]

More info here :-
viewtopic.php?f=3&t=22527&hilit=a+spec+1st+gear&start=0

[monte chris]

Thanks for all the help.