final drive between a and a+ gearboxes?
Turbo Mini Forums

hi, i plan to run a close ratio gearbox from a 1275gt, and am looking at changing the final drive.

are the final drive (crown and pinion wheels) interchangerble between a and a+ gearboxes?

also, am i right in thinking that you can run an a series gearbox with an a+ engine if the a series drop gears are used? many thanks

Yes!

You need the a series transfer case as well as the drop gears are different sizes.

You can buy conversion bearings so you can use the A+ gearbox case or transfer case with an A idler gear

how hard are the a series idler cases to get hold of second hand? are they the same for all a series engine, or is the 1275 one specific to the 1275 engine?

are the a + bell housings compatable with the a series idler case?

many thanks

The transfer housing should, ideally, be considered as part of the gearbox anyway as they are allegedly matched machined as one for the idler gear bearing recesses. In practice I think it makes little difference but the bearing recess in an A housing is certainly a different size to match the A gearbox casing. Availability second hand is I guess, about the same as early gearbox casings as that's what they belong with. I have a couple but I'm intending to use them on A+ gearboxes with the bearing sleeve Sprocket mentions so I can use A drop gears on an A+ box.

The only difference I'm aware of between small and large bore is whether the breather boss exists or is drilled/tapped. Also, the later ones sourced from Metros have an additional lug/drilled/tapped hole near the starter pinion for the Metro engine mount.

The WOK (I assume you mean this by "bell housing") are all the same apart from whether the little hole at the top for looking at the original timing marks on the flywheel exists or not. Metro sourced ones may have plastic plugs in the Mini engine mount holes but are usually drilled tapped anyway.

Edited by Rod S on 9th Aug, 2009.

Schrödinger's cat - so which one am I ???

hi, thanks for the replys. i have had a quick look on mini spares website but cannot find what you hjave described.

what i will be doing is using an a gearbox on an a+ block. from what i understand i will HAVE to use the a series transfer gears

just to make things clear, there is a bearing i can buy (for the transfer case) that will allow me to use the a series gearbox, a series transfer gears but with the a+ transfer gear housing?

sorry to drag this out but need to know exactly what im after.

does anyone know who stocks such bearings?

am going to start with the build next week, and dont have and a seires transfer gear casings, only a+.

many thanks

http://www.minispares.com/Product.aspx?ty=...R%20GEAR%20CO...

I have a spare pre a+ 1275 transfer housing and drops.