6 replies to this topic

[Guess-Works.com]

Q: Is a 1275 gearbox different to a 998 gearbox ?

A: No, the differences in actual gearbox construction are limited to the type of gearbox, not the engine...

Q: Is a turbo gearbox stronger than a std gearbox ?

A: No, physically the boxes are exactly the same in construction as are the majority of the parts contained within, the ONLY real difference with the TURBO gearbox, is not actually in the gearbox itself but in the transfer case. The spigot ( or nose) bearing on the TURBO's input shaft is bigger than the std box.

Q: Can you fit an A series engine onto an A+ box and vice versa ?

A: Yes, what you do need to make sure though, is you have the right transfer (drop) gears for the gearbox and not the engine. There is also a clearance issue with the earlier 850/998 3 synchro gearboxes and the 1275 engine

Q: Was there an A+ close ratio gearset fitted to the SPi/MPi coopers ?

A: No, There are two forms of A+ gearset, the std ratio gearset, and a WIDE ratio gearset (identifiable by the double groove in the teeth). This gearset was generally used on economy metro models which used a longer final drive, however did find it's way into some mini's in the 90's, mainly for export.

If you have evidence to prove the above untrue then I'd like to see it. I will continue to add more 'myths' as I come across them, or if you have any you think need to be put in this list then please post.

[Pie]

GW, theres also the myth about sc gears being stronger than Helical.

[Guess-Works.com]

That's possibly more of a matter of opinion than fact or myth...

There are some SC boxes, take a 4 speed dog box, which is a lot stronger than a std helical... but that's because the gears are actually bigger... and there's also the materials used in the manufacture of gears.

but if you took a like for like comparison then, your possibly right.

[duncancallum]

my understanding is helicols are stronger if you discount the affect of side loading on them to bearing wear. due to the extra material in them.

[spembo]

What is it that causes the crunching when shifting from 3rd to 2nd has ive heard conflicting theorys????

[duncancallum]

normaly worn syncro

[Guess-Works.com]

worn baulk ring to be precise... the synchro hub just engages the dog teeth... the baulk ring is the bit which does all the work, synchronising the speed of the synchro hub and the gear before they are engaged...

But, these are not myths... these are facts... and could do with being put into another thread...