1972 Mini Cooper E.

28246 Views 44 Replies 13 Participants Last post by onegreenev, Aug 2, 2014

Jaesin

Discussion Starter · Oct 31, 2011

10

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).

12V+:
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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Jaesin

Discussion Starter · #2 · Oct 31, 2011

The torque curve for the motor I bought.

Full res original: http://www.colorado.edu/physics/EducationIssues/podolefsky/EV_project/motor_sheets.png

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MalcolmB

· #3 · Oct 31, 2011

Hi Jaesin. Sounds like a good plan. I'll be watching this. Will you fabricate a new end plate for the gearbox or just modify the existing one? Last time I looked at the gearbox it seemed there might be enough room to fit in a chain drive if you used fairly small sprockets.

Those DC converters look familiar

Salty9

· #4 · Oct 31, 2011

Jaesin,

Just commenting to subscribe to the thread. As an aside, from my experience with bicycle chains, I would make sure that the drive chain could be serviced with a minimum of disassembling.

dtbaker

· #5 · Oct 31, 2011

Salty9 said:
Jaesin,

Just commenting to subscribe to the thread. As an aside, from my experience with bicycle chains, I would make sure that the drive chain could be serviced with a minimum of disassembling.

chain-drive will be fairly noisy... and you need to be sure you have a way to adjust tension as it wears. You may want to consider the rubber belt drives found on some of the big touring motorcycles; much quieter and no lube required.

charliehorse55

· #6 · Oct 31, 2011

dtbaker said:
chain-drive will be fairly noisy... and you need to be sure you have a way to adjust tension as it wears. You may want to consider the rubber belt drives found on some of the big touring motorcycles; much quieter and no lube required.

With belt drive you will still need way to adjust the belt tension, correct? The distance between the motor and gearbox would still have to be adjusted.

dtbaker

· #7 · Oct 31, 2011

charliehorse55 said:
With belt drive you will still need way to adjust the belt tension, correct? The distance between the motor and gearbox would still have to be adjusted.

yes, you still need a little adjustment to tension and/or have an idler pulley

Jaesin

Discussion Starter · #8 · Oct 31, 2011

dtbaker said:
chain-drive will be fairly noisy... and you need to be sure you have a way to adjust tension as it wears. You may want to consider the rubber belt drives found on some of the big touring motorcycles; much quieter and no lube required.

I am expecting the whole system to be pretty noisy. This motor and controller is kinda noisy. It makes this crazy tone at low RPM's before the PWM frequency changes. The transmission will probably be noisy. Maybe I'm wierd but I sorta like the odd sounds. Maybe because I've got no radio.

I drive motorbikes and I also have a Chinese electric scooter that I upgraded to LiFePO4. That thing is too quiet. I sometimes think that could get me in some trouble.

Thanks for the suggestions about chain tensioning. I am planning to use a Susuki GSXR Motorcycle chain. I am thinking to build in some tie rod style or pivot bolt style adjustments into the motor mount.

I am still working out how to switch the input gear with a sprocket. If I can manage to fit a small enough diameter gear, I will keep the stock end plate. That would be really nice. We'll see how it goes.

Malcolm:
I've seen your car, It is amazing work. Your motor setup blows my mind every time I look at it and I do love the green.

My motor test from last month:

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spdas

· #9 · Nov 1, 2011

aloha, looks like you got an original Cooper S. Why not repair it, sell it, and buy a regular Mini. In the US, Cooper S's in nice shape I see going for $25k+

Francis

Jaesin

Discussion Starter · #10 · Nov 1, 2011

spdas said:
aloha, looks like you got an original Cooper S. Why not repair it, sell it, and buy a regular Mini. In the US, Cooper S's in nice shape I see going for $25k+

Francis

Aloha Fransis!

I'm not sure it's a real Cooper S.

I was told it is but it only had the 998CC engine and it doesn't have disc brakes (yet).

I don't know that much about all of the different models.
Did they make a 1 liter Cooper S with drums in '72.

My theory, if it's worth $25K on gas, it's worth $50K to me on LiFe.

-J

spdas

· #11 · Nov 1, 2011

Aloha, It is a strange model then. As the 998 is the later Cooper engine, 997 was first. But I think the Cooper S came with 998, 1071 and 1275 engines. I never heard of a Cooper or Cooper S with drum brakes in front. And it has the right hand Cooper S gas tank (making twin tanks). So it is a real oddity to me. Someone in the UK would have to figure it out then. But it will make a nice EV!

Francis

Jaesin

Discussion Starter · #12 · Nov 1, 2011 (Edited)

spdas said:
Aloha, It is a strange model then. As the 998 is the later Cooper engine, 997 was first. But I think the Cooper S came with 998, 1071 and 1275 engines. I never heard of a Cooper or Cooper S with drum brakes in front. And it has the right hand Cooper S gas tank (making twin tanks). So it is a real oddity to me. Someone in the UK would have to figure it out then. But it will make a nice EV!

Francis

The twin tanks do look original. I tried looking up the VIN (MXA251 717-850N) one day but it wasn't conclusive. I think it might be Australian made (Near Perth). Made by Morris BMC. This is kind of a hunch. When I got the car, it had what looked like old New Zealand plates and the VIN doesn't look like a UK VIN. It was original (besides being repainted) with no rust at all. They did make a Cooper S model but I read AU cars had some different features. Maybe they ran drum brakes in AU.

I don't really know.

-J

Duncan

· #13 · Nov 2, 2011

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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Jaesin

Discussion Starter · #14 · Nov 2, 2011

Wow Duncan, Thanks for all the info.
Does that cover Aussie cars as well?

I read that they started installing roll up windows in Australia before they did on UK cars. Being that the environment is different, I imagine there are other inconsistencies as well.

I don't have hydrolastic suspension.

Whatever my car is, It's not a UK Cooper S so even if it was an Aussie Cooper S, It's still not worth what an original UK Cooper S is worth. By time I'm done with it, it will be very something completely different anyway. A custom Cooper E with adjustable suspension and all wheel disc brakes.

Duncan said:
Hi Guys
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

Man.. 1430cc sounds like a monster, hahaha.

The gearbox is a spare. I have the rest of the engine if anyone is interested in it (998cc "99H791P"). I need to get rid of it.

I will probably go by the local Mini supply shop to pick up the suspension parts on Thursday. Is there anything I will need to match the gearbox to my '72? I guess I will have to check the gearbox in the car before I go. What should I look for to tell which gearbox is in the car.

The Coil Conversion:
http://www.7ent.com/products/coil-spring-conversion-with-adjustable-struts-for017.html

- Jaesin

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Duncan

· #15 · Nov 2, 2011

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

Gearboxes

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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MalcolmB

· #16 · Nov 2, 2011

I agree with Duncan about the coil setup and brakes. I've looked at doing this at the front and rear (with a beam subframe). The consensus on the UK mini forum is that the standard rubber doughnuts and brake setup are very good and you can waste a lot of time and money trying to improve on them. The most cost-effective way to improve handling is to fit new doughnuts and dampers, as the rubber doughnuts last about seven years before stiffening up. Since you'll be changing the weight distribution it's also worth fitting hi-los – replacement suspension cones that let you adjust the ride height front and back.

As for brakes, the front drums are actually pretty good if well maintained. The 8.4" discs are a significant improvement. It's not worth doing much at the back, as the performance of the existing drums if well maintained is more than you can use – it's limited by the proportioning valve, as Duncan said.

I'm fairly sure you'll also need the later drive shafts to mate with the pot (CV) joints on your replacement box.

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Duncan

· #17 · Nov 3, 2011

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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Jaesin

Discussion Starter · #18 · Nov 4, 2011

First of all, I just want to say thanks for helping me keep my focus on this project.

Duncan said:
I would be very wary of that coil spring set-up
The mini doughnuts are very progressive - they have to be because of the

I was originally thinking about adjustablilty. I've had the car for about 6 years now and I think the cones are a bit harsh for daily driving so I kinda wanted to try something different. I think these are even cheaper than the doughnuts: http://www.gbcarparts.com/proddetail.asp?prod=SR-SpringsRED so I still might try them. I've read some post from a few guys that have put them on: http://www.miniaddicts.co.uk/forum/showthread.php?t=954, http://www.theminiforum.co.uk/forums/index.php?showtopic=65132

Duncan said:
The cooper gearbox had a nice aluminium extension going to a shorter gearlever,

This is what I have. A long rectangular aluminum tunnel attached to the gearbox. Complete with floor hump by the driver's seat (RHD). I am not sure if the tunnel will attach to the rod change gearbox. It doesn't look like it.

Inner CV Joint:
http://www.gbcarparts.com/proddetail.asp?prod=DT-CVJointInner&cat=19

Anyone know what's invovled with converting to inner CV joints?

MalcolmB said:
As for brakes, the front drums are actually pretty good if well maintained. The 8.4" discs are a significant improvement. It's not worth doing much at the back, as the performance of the existing drums if well maintained is more than you can use – it's limited by the proportioning valve, as Duncan said.

I mainly wanted the rear discs for cosmetic and weight saving but I am going to hold off on all not essential upgrades for now. It's a good point to think about the cost of all this stuff. I was getting a little too excited about wasting money. hahaha.

The last couple of years have been hard on "Champ". I am going to need to do a fair bit of body panel work. I should definitely take care of that and get some new paint before wasting money on stuff I don't need.

- Jaesin

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Duncan

· #19 · Nov 5, 2011

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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Jaesin

Discussion Starter · #20 · Nov 5, 2011

Thanks Duncan!

Duncan said:
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,

Sracer advertises that the springs are progressive. http://www.sracer.com/catalog/products/srp001.htm. Maybe not as progressive as the cones. Who knows, it's hard to get specs for these things. I had new doughnuts on it when I got the car but maybe they were not late model replacements. It could be that the seller wasn't perfectly honest.

I do appreciate you keeping me informed.

Duncan said:
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

So I guess I will need to rebuild the diff to use the older output shafts because I don't really want to buy new CV joints and axles at the moment.
Maybe it's possible to get standard axles but the ones I have sourced so far are beefed up $500 units. Ouch!

-Jaesin

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