A and A+ gearbox guts swapability.

A and A+ gearbox guts swapability.

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Discussion

love machine

Original Poster:

7,609 posts

242 months

Tuesday 16th May 2006
quotequote all
Can I throw a SCCR 4 synchro "A" gearkit into an A+ box?

Just bought some new A+ dropgears and picked this box up cheap..... Hopefully I can use it...


Cheers, Stu

guru_1071

2,768 posts

241 months

Wednesday 17th May 2006
quotequote all
the layshaft and laygear wont fit. the bearing at one end is bigger.

curses!

mr dann

Original Poster:

7,609 posts

242 months

Wednesday 17th May 2006
quotequote all
Ahhhh damn.

So, can I get the casing machined for an A+ Idler?

Blinking bargains.

guru_1071

2,768 posts

241 months

Wednesday 17th May 2006
quotequote all
its line bored to suit the end case.

hand in pocket time!!!

id just get the correct case - far cheaper

mr dann

Original Poster:

7,609 posts

242 months

Wednesday 17th May 2006
quotequote all
I've pulled an article off the net about swapping them over and I can't make head or tail of them yet to see what is what. It is about putting cooper s 4 sync gears in an A+ box, the snag is that some very late 1275GTs and early MG Metros had A+ close ratio gears, these are very rare. With regards to my problem, I think I have to use the A gears on the A+ mainshaft and then the A layshaft and gear, the layshaft/mount has to be modified as it "is wrong" Something about moving the slot on the layshaft a weeny bit to hold it in. I believe the shafts are the same otherwise. I'll have both boxes to bits at some point and see how they are different. There is some sort of a snag.

It would be good to speak to someone who has actually done it. I believe that a ST 4 sync kit has better ratios than the later A+ stuff.

I will do it but would rather use an A+ case as I have a spanking one with all new bits.

guru_1071

2,768 posts

241 months

Wednesday 17th May 2006
quotequote all
mr dann said:

It would be good to speak to someone who has actually done it.


you are.

its a nightmare.

mr dann

Original Poster:

7,609 posts

242 months

Thursday 18th May 2006
quotequote all
Thanks.

Vegard from the mini scene says that the whole lot fits into an A+ box with no worries. He seems to think that there is a snag putting the A+ stuff in an A box, something to do with it not fitting!

There seems to be confusion about what is required. I would have thought that if the A gearkits fitted as simply as that, there would be no mentioned difference between them. I don't think there is a problem with the laygear this way but am sure that there must be some snag with the 1st motion shaft and the relevant bearings.

This is precisely the snag, some say "I've done it and it's easy" and some say "Ooooooohh, nightmare". I suppose I'll have to have a proper look at the 2 exploded boxes, the relevant manuals and then find out myself. If it saves me about £300, I'm prepared to spend £300 of my time making it work and finding out the detail. If it fails, I'll put the whole thing on ebay.

guru_1071

2,768 posts

241 months

Thursday 18th May 2006
quotequote all
its the way you worded your question thats confusing....

so...

the a series innards will fit the a plus case...

however just the a series kit on its own wont as the main shaft end is bigger on an a plus. you would either need to bore the a series first motion out, or grind the a plus mainshaft end down, you also need to use the right layshaft.

its easier to use the entire innards from the a series box.

mr dann

Original Poster:

7,609 posts

242 months

Thursday 18th May 2006
quotequote all
That's what I was trying to do, I read Keith Calvers article on it from minimania.com and it was as confusing as my question!

So, the A whole lot goes into a A+ case, fantastic!!!

Job done and a gearbox for £100 instead of about £600

chuggaboom2

31 posts

246 months

Thursday 18th May 2006
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I think the only difference between A and A+, S/C or Std, is the size of the smaller end of the lay gear shaft/bearing. The size of the part of the shaft that goes into the gbx casing is actually the same, but you do need the larger hole thrust washer to match that is of the right thickness aswell to move gear sets from casing to casing.

Not sure if you can go from A+ to A casing wise but why would you want to as the load capacity and hence wear rate of the larger A+ lay gear/bearing is better.

My original 1275GT box had the larger size bearings, lay gear and drop idler, but wasn't designated as an A+ casing.

G.

mr dann

Original Poster:

7,609 posts

242 months

Thursday 18th May 2006
quotequote all
That's one of the rare crossover boxes that confused Calvers article.

Did the gear teeth have square tops or the A+ profile?

chuggaboom

1,152 posts

255 months

Sunday 21st May 2006
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I'm not aware of any difference in gear teeth profile...

...but that could be down to my age or lack of memeory...or both !

mr dann

Original Poster:

7,609 posts

242 months

Sunday 21st May 2006
quotequote all
It's a metro challenge gearset so useless for my road car. It's on ebay now. Bloody waste of money.