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1972 Mini Cooper E.

28268 Views 44 Replies 13 Participants Last post by  onegreenev
First of all, I would like to let you all know that all of your hard work has inspired me to start my conversion a year earlier than I initially planned.

My car is a 1972 Mini. I have owned it since 2005. The engine has smoked since I got it and I've been dreaming for years now about ways to get away from this nasty old oil puffing raga-motor.

For those of you who've had any experience with this car, you know that space is the main issue with it. The car was very well designed and wasted no space at all.

The Transmission:

Most folks think the stock trany isn't of much use. I mostly agree with this. It sits in the oil pan of the ICE. Basically, it is the oil pan. It also sits in kind of an awkward position. It's right in the middle. there is a few inches in front of it, and there is a few behind it but not really enough space to put any batteries or the controller.

I'm using it anyway:
The thing is, I am converting this car in two stages. I want to get rid of my other car so I am converting this car now. That way, I can drive it while I work on the car's more permanent AC system. That means that quick and dirty (AKA, fast and cheap) DC system for now.

Slap Chop:
A very nice gentleman I met at the EVVCON sold me a Curtis DC Controller with a contractor, heat sink and two fans already assembled. On top of that, he offered it to me at a very good price. Thanks Einar!

Coils and armatures:
I picked a D&D 6.7" motor (that's right, just one). It puts out a bit more torque @ 1600 RPM's than the stock ICE peak torque of 52 lb-ft @ 2700. The D&D would put out 80 ft-lbs @ 1600 RPM if I could give it another 83 amps.

Connecting Bits:
I am going to use a chain drive and nix the clutch. The output shaft of the motor and the input shaft of the gearbox were at a one-to-one ration so I am going to gear up the motor a bit. I want to have some usable torque at 65 MPH and I figure most people don't really use 1st gear. I'll aim for a about a 2-1 chain drive (calculations pending).

I am currently working on the DC-DC Converter. I bought some 3.3V Vicor modules that I will wire the output in series for a max of around 20A @ 13.5VDC.

Some Pictures.


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Hi Guys

Cooper S
started with a 1071cc large bore engine - there were 970cc and 1275cc variants - the last 1275cc S was made in 1971
It had hydrolastic suspension

The Cooper started with a 997cc and a pair of dinky disc brakes that were less effective than the drums
went to a 998cc with discs that were as good as the drums
The S came out with a pair of slightly larger discs
the 1275GT has a different block, crank, rods and bigger discs (need 12 inch wheels)

I think you have a mini 1000 with an extra tank! - is it hydrolastic?

If so remove the hydrolastic bits and fit the rubber suspension (preferably from a 1977 or later)

I don't think you will be able to sell it as a Cooper S

You seem to have a rod change gearbox - that came out in 1973 and has a completely different exhaust tunnel and much better driveshafts - much better my old 1430 used to bend the old rubber hardysplicers - I got used to changing them fast, the inboard CV joints are much better
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Hi Jaesin
I would be very wary of that coil spring set-up
The mini doughnuts are very progressive - they have to be because of the limited travel
the advert says
Road handling will be similar to rubber cone suspension, but with a big improvement in ride quality.
- simply not possible with a steel spring
lot of money for a retrograde step

Why do you want discs on the back? - the drums have to be limited by the proportioning valve

Aussie minis
They did some strange things but not I think cooper S's


The earliest gearbox had a meter long gearshift lever coming straight from the gearbox - horrible

The cooper gearbox had a nice aluminium extension going to a shorter gearlever,
(the cooper box has the extension bolted to the gearbox - the old 1100 had a similar unit bolted to the gearbox through a rubber mount)

in about 1972-73 the rod change gearbox came out this has two rods going back to a housing bolted into the exhaust tunnel - this gearbox also came with the inner CV joints

My 1430 had a cooper box with the diff bits changed to have the inner CV joints,(after I had broken a lot of the older joints)

One of the problems with the old minis was the engine/gearbox unit used to try and tear itself loose, - mainly torque reaction

The advantage of the old cooper box was the long aluminium extension gave a nice long lever to stop the engine from rotating

Look at your exhaust tunnel - the pre-rod change shells had a bulge near your left foot, in the very first minis there was a floor mounted switch there
the later exhaust tunnels are much squarer without the bulge

I think you can use the earlier shells for a rod change but you may need to make a mounting bracket and dress the exhaust tunnel out a bit

My 1430 went for about 40,000 miles then the 1430 A series was a bit tired so I replaced it with - a 2000cc Lancia twincam + holbay cams and a pair of webers
Fun days!
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Hi Jaesin

There is one suspension mod I would recommend
Longer front lower suspension arm,

If you can get a blank you drill the tapered hole for the bottom ball joint 6mm further out otherwise you cut two arms and weld them together - they are H section so it is easy to fill the H with two reinforcing bars and weld the whole mess together

Another tip - don't try and use a sexy small steering wheel
a powerful mini has torque steer - it can rip a small wheel out of your hands

We used to laugh at the guys with the small wheels as it showed they were show not go

otherwise there is not a whole lot worth doing - unless you replace the whole suspension
The adjustable Hi-Lo's are useful but you can do the whole thing with washers and a file
(much easier with the Hi-los)
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Hi Jaesin

Replacement springs
The problem is the mini has a short wheel travel and small wheels -
the springs have to stop the wheel movement when you hit a bump before you hit the bump stops
(this is why soft springs sometimes feel very hard - you are hitting the stops)

A simple steel spring has a constant rate (lbs/inch) so if it is going to stop the movement in a short distance it must have a very high rate,

The rubber doughnuts have a rising rate - so they are softer in normal use but can still absorb that big bump

Steel springs don't work - the only reason these people are reporting otherwise is because they have spent the money or their old system was knackerred and the have fixed it at the same time

Malcom suggested replacing them with new ones - the early ones were stiffer, in 1977 the factory went to softer units
if you have 1972 units they are both stiff and old

If you have some spare ones some people used to soften them by drilling holes in the rubber
try about 4 off 1/2 inch holes - the holes will go a funny shape when you take the drill out - this is normal

If you have spares you can do a suck it and see

Later drive shafts on an older gearbox
I did this on my 1430
You have all of the bits you will need on the other gearbox, take the diff side covers off - I think you will need the diff output shafts

If you get a later disc brake setup you will need the CV's and drive shafts as well
Its all pretty clear when you get the bits together
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Hi Jaesin

You just need the front hubs and driveshafts off any post 1984 mini - they all have the disc brakes after 1984.
I think you will need 12 inch wheels - the Cooper S brakes that can be fitted in 10 inch rims are like hens teeth

The inboards CV's don't seem to wear out much - the outboard ones only fail when they get grit in them

The diff is dead easy - practice on the spare gearbox you have - just take off the side covers - undo the fore-aft bolts and it comes apart

You should check that your old diff has the same input gear - if it has just drop the new diff into your cooper box and bolt on the side covers - if it has a different gear swap the gear from your old diff first

Swap the diff over - swap the side covers and you have a cooper gearbox (I think they were also fitted to std minis for a few years - if you have close ratios it's a cooper unit) with inboard CV joints
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