10 replies to this topic

[alpder]

I have a magic wand Mk2 estate. And I have two complete engines here:

 - 1275cc Metro A+ with 3.1 diff and 'rod' change.

 - 850cc A with 3.765 diff and a 'direct' (i.e. magic-wand on a remote casing) gear-change.

 

I had originally planned to strip the A+ gearbox and move the relevant parts into my A box, then mate it with the 1275 to give me a magic-wand 1275 with a 3.1 FD.

 

But, reading around, it seems that A+ and A diffs are not interchangeable. And the longest A diff is 3.44.

 

So before I move on and find alternatives, I'm just double-double-checking with the knowledgeable that I really *can't* put an A+ 3.1 FD into my A magic-wand/direct box?

[nicklouse]

They are interchangeable but as a set. And for some the retainer might need reliving.

 

what I would be more concerned about I’d the crank hitting the gearbox casing. Some of the early casings did not have the clearance for the crank on the 1275s. Can be fixed with some time and a die grinder.

[Lplus]

I have a magic wand Mk2 estate. And I have two complete engines here:

 - 1275cc Metro A+ with 3.1 diff and 'rod' change.

 - 850cc A with 3.765 diff and a 'direct' (i.e. magic-wand on a remote casing) gear-change.

 

I had originally planned to strip the A+ gearbox and move the relevant parts into my A box, then mate it with the 1275 to give me a magic-wand 1275 with a 3.1 FD.

 

But, reading around, it seems that A+ and A diffs are not interchangeable. And the longest A diff is 3.44.

 

So before I move on and find alternatives, I'm just double-double-checking with the knowledgeable that I really *can't* put an A+ 3.1 FD into my A magic-wand/direct box?

I'm surprised you can put A+ gears in a magic wand gearbox.

[alpder]

Thanks Nicklouse and Lplus.

 

Minimania have a vid showing an A+ layshaft going into a 4-synchro A box with only a very minor mod to the casting. Whether the main shaft can also be swapped isn't clear. Though neither of those are what I need to do, anyway. But it shows that A+ cogs (at least some of them) can be used to rebuild an A box even though replacement A parts might not be available.

I'd only want to swap the FD and (assuming parts are not excessively worn) I would reuse all the A gears. With new baulk rings etc of course.

 

This page http://www.dummett.n...inal_drive.html says "A+ and A series ARE NOT interchangeable". But it's unclear quite what that means. (A/A+ diffs/boxes can't be mixed? Or only that A/A+ crowns/pinions can't be mixed?)

 

Regarding 1275 crank interference with the A gearbox casing, that's apparently only an issue with very early A gearboxes and unlikely to be a problem with my late 4-synchro remote box. Certainly, there looks like plenty of room in there at first glance. I need to get them side-by-side on the bench to be sure but it's not a showstopper anyway - Dremel can fix it!

[mini13]

I take that as A and A+ gears are not interchangable due to the different tooth profiles

[Spider]

I'm surprised you can put A+ gears in a magic wand gearbox.

 

It depends on what type of 'Magic Wand' Gearbox it is - read below

 

 

Thanks Nicklouse and Lplus.

 

Minimania have a vid showing an A+ layshaft going into a 4-synchro A box with only a very minor mod to the casting. Whether the main shaft can also be swapped isn't clear. Though neither of those are what I need to do, anyway. But it shows that A+ cogs (at least some of them) can be used to rebuild an A box even though replacement A parts might not be available.

I'd only want to swap the FD and (assuming parts are not excessively worn) I would reuse all the A gears. With new baulk rings etc of course.

 

This page http://www.dummett.n...inal_drive.html says "A+ and A series ARE NOT interchangeable". But it's unclear quite what that means. (A/A+ diffs/boxes can't be mixed? Or only that A/A+ crowns/pinions can't be mixed?)

 

Regarding 1275 crank interference with the A gearbox casing, that's apparently only an issue with very early A gearboxes and unlikely to be a problem with my late 4-synchro remote box. Certainly, there looks like plenty of room in there at first glance. I need to get them side-by-side on the bench to be sure but it's not a showstopper anyway - Dremel can fix it!

 

 

As Nick mentioned above, the final drive gears are interchangeable as sets between A and A+ in any gearbox, though as Nick also mentioned, the 'C' shaped Mainshaft Bearing Retainer may need relieving from the A type boxes when going to anything longer than 3.44. It's an easy job, just remove the plate and a few minutes with a die grinder.

In regards to what's interchangeable within the gearbox itself, if the Magic Wand is 3 synchro type, then there's no A+ parts that will fit it (other than final drive and speedo drive gears). As Nick also touched on, there's only a few of these that will take a 1275 engine, those with casting numbers;-

 

22G190
22G333
22A1522

 

will all take a 1275 (and 1098) engine without modification. Some of the early gearboxes can be relieved to give clearance for the Con Rod Big Ends and some can't. The first 2 of these in this list ^ were mostly fitted to Cooper S models, so you could expect to pay a King's Ranson for them.

If your Magic Wand is a 4 synchro type, then firstly, the 1275 engine will fit, though on the odd one, some casting flash may need relieving, but no big deal. The Final Drive gears, as sets, will also swap over, between A and A+, though anything taller than 3.44 will require the retainer to be relieved. These gearboxes have casting numbers;-

 

22G1128

22G846 (rare)

As far as Gear Sets (1st-4th) goes, then - as sets - A+ Gears can be fitted in to the A Boxes (4 synchro only), though the small end of the Layshaft hole on the case needs some work and Reverse Gears can't be swapped from a Remote to Rod shift type box, but here you can run the (all synchro) Remote Reverse, with the Rod gear sets.
 

 

I take that as A and A+ gears are not interchangable due to the different tooth profiles

 

That's part of it. The other is with the gear sets, there's different tooth counts on some of the gears and so different diameters here too.
 

[alpder]

Thanks Spider.

 

My A direct/magic-wand box is the 22G846 4-sychro. It's hard to tell - yet - the state of the internals. The walls/floor of the casting - and all of the internal parts - are covered in caked-on soot which isn't a good sign. And the pinion nut wasn't even finger-tight when I came to undo it. So not sure how bad it's going to be when I get it further apart. But it's encouraging to hear that I can use the A+ parts if I need to. It's effing freezing here (UK) presently which doesn't encourage quick progress in the shed.

 

Any idea how much of the A+ diff I can drop into the A gearbox? The A diff is very sloppy. Clearly their bearings are different (the races are much wider on the A which seems odd because stockists only offer one size of bearing) but at first sight the two diffs seem otherwise the same. Possibly I could even drop the A+ one straight in, with its narrow bearings and all, if I used a lot(!) of shims.

[nicklouse]

Thanks Spider.

 

My A direct/magic-wand box is the 22G846 4-sychro. It's hard to tell - yet - the state of the internals. The walls/floor of the casting - and all of the internal parts - are covered in caked-on soot which isn't a good sign. And the pinion nut wasn't even finger-tight when I came to undo it. So not sure how bad it's going to be when I get it further apart. But it's encouraging to hear that I can use the A+ parts if I need to. It's effing freezing here (UK) presently which doesn't encourage quick progress in the shed.

 

Any idea how much of the A+ diff I can drop into the A gearbox? The A diff is very sloppy. Clearly their bearings are different (the races are much wider on the A which seems odd because stockists only offer one size of bearing) but at first sight the two diffs seem otherwise the same. Possibly I could even drop the A+ one straight in, with its narrow bearings and all, if I used a lot(!) of shims.

The whole diff ass can go in. Yes there were two types of bearings but they are interchangeable in any box just need to be the same and set up fir they type. Can’t remember the exact wording on them but the one with words say something like “thrust” but it is in the Haynes workshop manual.

[Spider]

Thanks Spider.

 

My A direct/magic-wand box is the 22G846 4-sychro. It's hard to tell - yet - the state of the internals. The walls/floor of the casting - and all of the internal parts - are covered in caked-on soot which isn't a good sign. And the pinion nut wasn't even finger-tight when I came to undo it. So not sure how bad it's going to be when I get it further apart. But it's encouraging to hear that I can use the A+ parts if I need to. It's effing freezing here (UK) presently which doesn't encourage quick progress in the shed.

 

Any idea how much of the A+ diff I can drop into the A gearbox? The A diff is very sloppy. Clearly their bearings are different (the races are much wider on the A which seems odd because stockists only offer one size of bearing) but at first sight the two diffs seem otherwise the same. Possibly I could even drop the A+ one straight in, with its narrow bearings and all, if I used a lot(!) of shims.

 

It's supposed to be summer here in Australia, yet, I sit here in my winter clothes writing this out and I heard yesterday that we have snow down to 800 metres,,,, what were they saying a few years back ? Global warming ???  I perhaps should add though, that they are experiencing a heat wave in the Northern Territory,,,, temps already in the mid 40's,,,, but I digress,,,,

 

I wouldn't worry too much about the the look of it in regards to engine blow by etc (the black 'soot') but as long as the case is OK, the rest of it can be sorted out.

As Nick mentioned, the complete Diff can be swapped over. The A+ diff (except the early ones) are the ones to use. They have a better set up for the Plant Gear Thrusts to stops them wearing the Hemisphere. I usually convert the A types to this arrangement when I overhaul them for others.

While the bearings appear different, dimensionally they are the same and interchangeable. There was a few types of bearings used here during production. I do prefer the full race / face types though for any performance stuff as the handle heat better and have more support surface area.

[alpder]

Thanks to everyone for the help and encouragement.

In the end I swapped the entire gearset and diff (except reverse) from the A+ box into the old direct box, with the usual new-replacement thrusts, baulk rings, bearings, etc. Nothing much visibly wrong with the A gearset, but the A+ engine was far less worn so I figured the gearbox was probably lower mileage. And somebody had, at least, changed the oil once or twice so that it was still runny enough to come out the drain plug without needing to be heat-gunned back to a liquid state. Whereas the 850 unit was filled with treacle-like goop

With a new knuckle on the gear-change rod the change feels pretty positive and tight... but I wonder how long it'll be until we're back to "they're all in there somewhere"?

The newly-built A+ 1310 engine will go on top. I'm stuck with using the A transfer/input gears, of course. With the A+ transfer-case - just because it needed less cleaning-up and I can keep the 'A' one for a more historically-correct build of something else later. (I'm keeping an eye out for a dead Mk1 Woody...)

The adaptations required were to put a small chamfer where the A+ layshaft spindle seats into the central web*, fit an adapter transfer-gear bearing in the transfer case, and drop an A+/A converter output onto the crankshaft. The A+ diff accepted the old-style yoke-ended output shafts though it also took a pair of 48-thou fibre washers... which it shouldn't have done apparently. But it feels alright so we'll go with it.

Surprising how little the engineering had changed in the 35 years between the two production dates. Either Issigonis was many decades ahead of his time. Or BL suffered chronic underinvestment. Surely not!

 

*Many of the YouTube help vids show using a Dremel for this. But I suggest a more controlled result and a better finish can be had using a cone-cut on a long extension shaft - a 4mm-25mm cone-cut has just about the perfect angle for it, and the long extension allows it to be lined-up perfectly through the front of the case. Tho' go at it slowly: it only requires a couple of turns to achieve the necessary countersink.

[whistler]

They are interchangeable but as a set. And for some the retainer might need reliving.

 

what I would be more concerned about I’d the crank hitting the gearbox casing. Some of the early casings did not have the clearance for the crank on the 1275s. Can be fixed with some time and a die grinder.

I had to do exactly that back in 1969 to fit a 1275 short engine onto my 3 syncro 850 box (circa 1961). A little patience and a grindstone to give clearance for the 1275 crank.