20 replies to this topic

[smileytony]

Sorry mate I'm probably not being very intelligent right now but...

The final drive AND diff need to match the casing that they are being fitted to. E.g. the link to Ebay I posted would have to go with a pre A+ case. If this was the case then all gears would need to be pre A+ as well.

With my case (which I'd rather use as I know it's not cracked etc) I need to find a diff that matches the A+ casing. E.g. the link you have posted.

You say I can't just bolt that diff I posted a link to into my case as the output shafts are the wrong size. I presume you are referring to the splined shafts the the pot joints are fitted to? Can the output shafts not be changed?

Thanks!
P.S Sorry if I'm being stupid!

Yep that'd do, doesn't matter whether it's A or A+ as long as you keep them matched and don't mix them up. You couldn't just bolt that diff in your box as the output shafts are the wrong size if your keeping the pot joints. Changing to the rubber couplings would be a bad idea.

Here the one I saw http://cgi.ebay.co.u...a...A1|240:1318

[Nightrain]

No probs, the final drive is the actual ratio of the crownwheel and pinion together they are the final drive. It gets confusing when people call them the diff. Which is actually the piece that the crownwheel bolts too.

You can use any final drive in the A+ box, you need to keep the crownwheel & pinion as a matched pair ie you can't use a A+ pinion with a A series crownwheel. In an ideal world you'd actually keep the two together because they will be worn/run in to each other. With the earlier A series box you can use upto a 18 tooth pinion iirc any bigger and the third motion shaft bearing retainer needs machining out so it clears the larger pinion.

Yes if you got that one in your link you'd just unbolt the crownwheel (big gear) from the diff remove the output shaft and replace them with the parts from you pot joint diff ie. the output shaft and the actual diff. If you go with the Minispares diff you gonna be stripping it anyway, hardest part is removing the diff bearings from the output shafts without breaking 'em. But a worth while upgrade if you can stretch to them would be a new set of diff bearings that are full width bearing rather than the *poop poop* standard ones.

[smileytony]

Thank you! I think that's made it pretty clear now. I understand that you can't intermix the A and A+ crownwheel/pinion setups.

Brill, so the one that's for sale locally to me might be usable. Fantastic. Worth an email me things!

Cheers!

No probs, the final drive is the actual ratio of the crownwheel and pinion together they are the final drive. It gets confusing when people call them the diff. Which is actually the piece that the crownwheel bolts too.

You can use any final drive in the A+ box, you need to keep the crownwheel & pinion as a matched pair ie you can't use a A+ pinion with a A series crownwheel. In an ideal world you'd actually keep the two together because they will be worn/run in to each other. With the earlier A series box you can use upto a 18 tooth pinion iirc any bigger and the third motion shaft bearing retainer needs machining out so it clears the larger pinion.

Yes if you got that one in your link you'd just unbolt the crownwheel (big gear) from the diff remove the output shaft and replace them with the parts from you pot joint diff ie. the output shaft and the actual diff. If you go with the Minispares diff you gonna be stripping it anyway, hardest part is removing the diff bearings from the output shafts without breaking 'em. But a worth while upgrade if you can stretch to them would be a new set of diff bearings that are full width bearing rather than the *poop poop* standard ones.

[smileytony]

Also am I right in saying that the 12H engines came with 3.44 FD's?

Thanks!

[Guess-Works.com]

No, 12H just means it's a 1275cc Transverse mounted engine, the actual gearbox and final drive configuration is dependant, as are the other ancillaries, on the engine code which is the next series of numbers/letters..

What you will find is that most pre late 80's mini engines will have a 3.4 final drive, so the most common of all the FD's available.

[smileytony]

Thanks everyone, it's been really useful.

It's amazing how many different opinions people have. I popped to see the guy locally to me that rebuilds, races etc etc with minis (it's his full time job as well as his hobby), and he was horrified with the spec of the gearbox for the engine.

It makes it all confusing!