Automatic gearbox question

[360gts]

Was thinking...what a great piece of engineering in the Mini auto gearbox...so, leads to this question....
Just how much horsepower will it take?

My friend has one...went for a drive in it...lovely smooth shifting.....
Was thinking....one of these with a good 1300 power unit might be a good prospect. We did have them here in the Austin America......those have gone the way of the dodo bird.
I have a complete unit sitting here...interested in hearing if anyone has pushed the envelope with one of these.

[Spider]

Hey Dermot,

I agree that they are a wonderful but of engineering and decades ahead of any other production Auto Gearbox at that time.

While i have very limited experience with them, they will easily take moderate increases in engine output, personally, I think the ones to work from are the AP1 Gearboxes, but modified with some AP2 parts, like the 1275 forward clutch and top gear band.

The 'problem' with Autos and modified engines is that you are limited with how far you can go with the engines in terms of modifications - there are no alternative gear ratio sets, there are (for all intents) no alternative final drive ratios and the stall speed of the converter also doesn't suit much beyond a mild street cam, though, you could have that modified, but you'll spend a chunk of cash having it done if you can find anyone who'll take it on.

Of course, like any other part in the car, as soon as you put the torque and power levels up, the life comes down.

[Polarsilver]

Dog Walker passing & looked at my cars .. He told me he was the Publicity Manager for AP back then told me the Manager of the RD department at AP had prepared a privateer Rally Cooper S with the Auto Box .. i did ask him if he had any stuff hidden in his loft from back in the day & he said he had moved house several times but he would have a look.. i have no other info on this Auto Box Rally Car ..maybe its out there ?

[360gts]

Hey Dermot,

I agree that they are a wonderful but of engineering and decades ahead of any other production Auto Gearbox at that time.

Hi Chris,
I suspect the torque converter may well be a weak spot....as it is in most auto trannys.
Still, I am considering using this one with a good 1300 engine....
Cheers
D

[underkut]

There is a company and website ( AP2world) that specialises in these gear boxes for spares and repairs. They also list parts for tuning modifications as well. Not sure how much power can be handled but my guess is these guys would know. I have bought some basic seals from them in the past and could not fault their service or costs.
Hope this helps.

[Striped shirt]

I know that Martin at AP2 World has done some impressive modifications to these. I have known him for sometime, really lovely fella. Proper old school (with some modern CNC kit) engineering company.

[Peter Laidler]

Am I missing something here ......... These auto gearboxes were troublesome and maintenance heavy (and marginal ?) right from the word GO. According to Unipart there was a constant demand for replacements. And unlike other exchange stuff, like engines and steering racks, dynamos etc etc. there were no (?) suitable commercial rebuilders who would undertake the repairs. So they went back to AP.

The problem, as I saw it, was that there were so many specialised tools needed for the average Joe with a broken auto box. My wife bought an almost new, just out of warranty Tundra auto mini from her friend in Newbury............ with a duff box. Mind you, because of the box, the almost new car was cheap. I tried to set about it but there was another problem......

A bit like hydrolastic, the schematics in the workshop manual didn't seem to relate to, well........, anything in her auto box. Mind you, I'm not the brightest light in the box when it comes to mechanicals and engineering. It was pure white-mans magic. So after a week or so of scratching my head I got a good 1000 manual engine/box from Dave Toomey in Pembroke Road. Great car thereafter except for the colour.

That's just me experience with the mini box. Or how I stripped it but never even identified the fault!

[mab01uk]

You might find this old thread linked below interesting...

Prototype Mini Automatic 1962:-
http://mk1-forum.net/viewtopic.php?t=1994