This blog post is about my design suggestions for an electric Morris Minor.
There have already been some prototype electric Morris Minor conversions already, which I will discuss.
In addition I have designed alternative ways to successfully convert classic cars such as the Morris Minor.
History & background
The Morris Minor is a British car designed by Sir Alec Issigonis, that was launched in 1948.
The Morris Minor originally was produced with an 918cc Side valve Petrol engine, but this was replaced in the early 1950s by an Overhead Valve (OHV) engine.
The OHV engine was improved and its size increased during the remainder of its production. and the later models were 1098cc in cubic capacity size.
The standard Morris Minor had the engine connected to a four speed longitudinal mounted gearbox, attached at the back of the engine.
The gearbox output is connected to a long single drive shaft, which runs underneath the car.
The drive shaft connects the gearbox to the rear axle.
The rear axle incorporates a ‘differential’ which fixes the speed ratio, between the rotational speed of the drive shaft, and the rotational speed of the road wheels.
Therefore as the engine power is transferred via the gearbox and drive shaft, to the rear axle, it is a rear wheel drive car.
Any design for an electric Morris Minor, will probably stick with the rear wheel drive configuration.
The reason for keeping the electric Morris Minor as Rear Wheel Drive, or RHD for short, is engineering design simplicity.
The front suspension on a Morris Minor was advanced for a British car of its time (1948).
The front suspension used torsion bars, as the springs, and featured ‘rack and pinion’ suspension, that is still used in modern cars.
The shock absorbers are different to the type used in modern cars, and are known as ‘lever arm shock absorbers’.
To convert an electric Morris Minor into powering the front wheels, known as front wheel drive, would require major suspension modifications (unless hub motors were used).
This is because the original Morris Minor steering and front suspension system, would need a lot of component changes.
Of course its possible to make a front wheel drive Morris Minor, but more expensive, and also changes the cars handling characteristics.
If however you are hell bent on a front wheel drive electric Morris Minor then its possible.
My solution would be to use hub integrated motors.
Hub integrated motors consist of an individual electric motor powering each driving wheel.
For instance to create a front wheel drive Morris Minor, you would have two motors driving each of the two front wheels.
If you wanted to use hub motors, but to keep the traditional Morris Minor rear wheel drive configuration, you would fit the motors to the two rear wheels.
So let’s decide to stick to the original rear wheel drive layout for our electric Morris Minor.
There are four ways that you could configure the electric motor layout. This also applies to many other classic cars, which share the same basic layout.
Firstly, the original internal combustion engine can be removed, whilst leaving the Morris Minor gearbox, driveshaft and rear axle (Inc differential) in place.
An electric motor is then attached to the original Morris Minor gearbox.
Some electric motor conversions that use this layout configuration, are clutch less in design. The torque & high rev range of many electric motors mean that the car can be driven in the same gear for most of the time.
Other electric car conversion designs still incorporate a conventional clutch.
The advantages of retaining a clutch are better motor speed control, and more importantly more retention of the original Classic Car experience.
A second option for mounting the electric motor in your Morris Minor, would be by removing the gearbox and either mounting the electric motor at the front end of the drive shaft, and directly attached to its front end.
Or alternatively the drive shaft could be removed, and the motor mounted directly to the rear axle differential input shaft.
This second method of attaching the electric motor directly to the rear axle differential connection, has advantages and disadvantages.
The advantage is a saving of weight, by removing the drive shaft which runs underneath the car, from front to back.
Less weight is a good thing for performance of your electric car.
The disadvantage is that it makes it a bit harder to mount, than if you mounted the electric motor at the front end, and retained the driveshaft.
It is harder to mount, because you need to create a mounting cradle which attaches to the rear axle, and supports the weight of the electric motor.
Morris Minor Hybrid
You may well of heard of Hybrid cars.
If not, then let me explain what they are.
A hybrid car is a car that uses a combination of combustible fuel, such as petrol or diesel, and electric power.
A hybrid car might drive the wheels using an electric motor at low town speeds, and petrol at higher speeds.
Alternatively, the petrol (or diesel) motor could be used, if the battery was low on charge.
The use of electric motors at low speeds around towns, has obvious environmental advantages.
However you might also still want a traditional petrol motor for long distance trips.
My design for a Morris Minor Hybrid, keeps the petrol engine, whilst also adding electric front wheel drive.
The rear wheels continue to be driven by the Morris Minors petrol motor.
Whilst the front wheels are driven by ‘in-hub’ electric motors.
A simple solution would be to have a manual switch, to be able to select the drive system.
Alternatively an automatic electrically controlled system could be used.
I am currently considering the design for an automatic system, and will provide further details in the future.
If you want design simplicity for your electric Morris, then keep the original gearbox.
The electric motor is simply attached to the gearbox, in place of the original petrol motor.
This is done via a special adapter plate, and a coupler.
The potential problem with using the original gearbox is excess motor torque.
Vehicle Electric Motors produce a lot of torque at low RPM (Revolution Per Minute).
The standard Morris Minor gearbox was designed to handle a maximum engine torque of 60 lb/ft (81 N·m) at 2,500 rpm.
The above torque figure is for the most powerful Morris Minor, built from 1962 onwards.
The gearbox was upgraded in 1962, along with the engine size (to 1098cc from 948cc), and gained Baulk-Ring-Synchromesh .
To ensure that you do not suffer premature gearbox failure, it is important that you consult electric motor manufacturers datasheets.
For an ordinary road going car, this should not be an issue, if precautions are taken to select a suitable motor.
For those looking to upgrade their Morris Minors performance, then this is definitely a consideration.
The characteristics of electric motors is instant maximum torque at very low rpm.
This sudden surge of torque needs to be considered, as it could damage the standard minor gearbox in a relatively short time.
The morris minor has been converted and upgraded for many years by enthusiasts, including the gearbox.
One popular conversion is to fit the Ford Sierra gearbox.
The Ford gearbox offers two advantages.
The first advantage, is that the Sierra gearbox gives you five forward gears, compared with the minors original four.
The second advantage of changing the gearbox to the Ford unit, is strength. The gearbox is stronger, and can handle more power.