Historic vehicle electrification

During COVID lockdown a sleeve slipped, caught a piston ring and exploded piston shrapnel into the oily fast moving internals of my 90 engine. While exploring options and biased by the lifestyle affecting costs of rebuilding the engine, the current push for everything EV, and the addition of solar panels to my garage roof, I decided to break through the barriers of the unthinkable and see if the thing could be electrified.

Of course it would be sacrilegious to transform the mechanics of a 90 with history from Brooklands, Ards and Phoenix Park, but hey I have the time, and purely as a thought exercise I decided to look at how it could be done.

Requirements

In order for the project to not totally destroy a historic Talbot I have the following requirements:

  1. Ability to switch between an explosion motor and electrical power within a week.
  2. Not to lose the character of the car when driving in EV mode.

Architecture

A typical EV motor has huge torque throughout an 8000 rpm range, and it can be made to move in either direction, so a gearbox and clutch are not strictly necessary given a good choice of motor. However this would break requirement 2.

Therefor the architecture would be, keep the electric motor at the front, use the existing clutch, gearbox and rear drive train.

A good choice of robust, simple EV motor could deliver about 120BHP which would increase the performance of the 90 without breaking the drive train (subject to judicious management of gearing/RPM/torque).

An EV motor generates heat, as do the batteries. Cooling is required, which means there is a use for the radiator beyond holding up the bonnet. An alternative water pump will be required.

Fabrication would be required to create a structure to support the radiator, provide a platform for the motor, connect to the chassis at the front and rear, and connect the motor in line with the gearbox. A 3D scan of the block/sump could provide a basic drawing that can be manipulated to create a CNC template for a suitable cradle. Pedals, brakes, handbrake, clutch, gearbox all work as normal 90. The oil supply to the silent third box has long since been disconnected. The throttle is a different matter, but the pedal linkage can be connected to a Hall Effect electric throttle using a cable, so the driver’s controls would be all original.

90 Electrics are 12V, an EV requires much Higher Voltages (more on HV later). The original 12V battery could be used to run the existing lamps and horn, and I would still have to wave to indicate turning or braking. Wipers were considered a weighty luxury, but there is a 12V socket. All good, but the battery requires charging, and this can be accomplished using a step down Voltage device that will charge the 12v battery from the HV system. No Dynastart.

Driver information tools become a mix of old and new. The original speedometer is still connected to the rear axle, the temperature gauge is still connected to the radiator. The primary tool (Rev counter) would be a problem to convert to show EV revs, oil pressure is not required, 12v charge state could be useful. Fuel and oil levels do not work anyway. A simple flip up panel could overlay the rev counter with a digital one to show EV revs, state of charge of HV battery system and any other information that can be delivered from an HV controller.

There is enough space under the huge bonnet, ground clearance and petrol tank to house a number of battery configurations.

All of which provides an architecture roughly like the following:

Vintage Talbot 90 EV architecture

With an architecture such as this, it should be possible to swap powertrains within a week (given some practice) and should satisfy requirement 1. The standard controls should allow it to feel like driving a Talbot, albeit with a change to torque which would require using the gears in a different manner, and satisfy requirement 2

So far so good, now here comes the thorny part.

Energy, range and weight.

The 90 has a 35 gallon tank, averages 15MPG on an exuberance setting, which gives it a designed range of approx 500 miles.

35 Gallons of petrol weighs approx 120KG, which adds a reluctance for the rear end to follow the front around a corner, and is one reason why i never fill it to the brim. 20 gallons is more usual giving a 300 mile range and enough weight (70kg) to roughly balance the car for most of the journey.

Batteries on the other hand are not as good at storing energy. 120KG typically gets you 22 Kilowatt hours. Converting KWH to range is a vague calculation involving a number of factors, the most important of which is weight. Assuming that the final weight of an EV90 is roughly that of a modern EV mini (1500kg, and the only Talbot model weight I can find being a saloon bodied 65 at 31cwt), we can just use the mini range figures which are stated as 3-4 miles per KWH.

So,

We should also note that

so we are dealing with approximations.

Replacing the engine, oil and exhaust pipe with a simple electric motor should deliver a weight saving, and it is the weight difference that is important for range, handling and stress on the other components. So what would be the weight difference of an EV90 without the batteries?

I ignored wifely protestations and, while the engine was dismantled, absconded with the bathroom scales to the garage to obtain the following in kgs:

Allow another 10 for all the bits I did not weigh (coil, distributor etc etc)

So we would lose mechanical components to the tune of approx 250kg plus the weight of fuel (20 galls = 70KG, 35 galls = 120KG etc)

But gain electrical components

So estimated EV component weight adds approx 100kg without the battery.

Lose 250kg but gain 100kg gives a lighter vehicle by approx150KG without considering fuel/batteries.

What is the comparable total weight difference per range?

Range / Petrol weight / Battery weight / Total EV weight difference (-150kg plus fuel diff)

Range

Petrol weight

Battery weight

Total EV weight difference

300

70kg

480kg

+260kg

500

120kg

720kg

+450kg

 

 

 

If we aim to keep the total weight roughly the same as Roesch designed it (see requirement 2 ) to preserve the functions of suspension, brakes, handling etc then we are looking at a 220kg battery (150kg mechanics replacement gain plus 70 kg petrol replacement) which gives 40KWH and a range of 120-160 miles.

These figures do not take into account the potentially substantial inhabitants required to drive, navigate and tell the driver what to do. Say 100kg (or is that just me) per person. However the electric mini also does not mention passengers in its range calculations which is another reason these figures are approximations.

My Brooklands 90 has lightweight AMS steering box, brake backs, and axle, the body is thin fabric covering an aluminium panel on an ash frame, and there are no weighty wipers, indicators or even a step to aid boarding. In short it is lean and mean. So it might be able to do a little better than the above.

Battery technology is improving, so there is hope that the above calculations may change, and there are developments such as hydrogen /battery/ fuel cell technology which could provide alternative energy stores in the future.

Is it worth doing?

A range of 120-160 miles before stopping to recharge seems too low given the distance between charge points, the time taken to charge and I rarely use the Talbot for local journeys. While stopping for lunch every 150 miles or so to charge might seem fun on the continent, UK services do not have the same cachet (apart from the excellent set up at M5 Quedgeley), and it seems like a recipe for an early handover of the car to a slimmer relative.

Value? Now here is another thorn. With the mix of forces such as just-stop-oil, synthetic fuels and ULEZ charges, added to a clash between authenticity and modernity, a market value separation between the best and the also-rans, the changing demographics of Talbot owners and the lack of EV engineering skills, it is a difficult conundrum. I would have thought that if requirement 1 were achieved then the best of both worlds is possible. To be authentic when it matters, and to be electric when it does not, would add value and future proof the car. Electrification only would limit its use, and turn it into something other than it was meant to be, but it would fit into a modern world. There are also simpler architectures for electric only which would remove the gearbox and drive train, and replace with rear axle mounted motor, but this would break requirement 1. I foresee increasing friction for the authentic only option unless the aspirations of owning historic vehicles are transferred to following generations in a world more conscious of environmental issues.

Then there is the Cost! I guess if your engine works well, then you only have an electrification cost. If like me, you have to rebuild an engine and also electrify it, It is a problem. A rough calculation in 2023 saw an estimated cost of an electric architecture (battery sized to keep original weight), equivalent to rebuilding the original engine.

So, am I going to do it?

Engineers and authentic/replacement components are only going to get more expensive as EV tech replaces controlled explosion tech. EV components should get cheaper and better as development continues. So for now I am paying to rebuild (hello Lee Langstone) that which I broke, but after that, finances permitting (unlikely - wifely ed.), it would be great to do both. In the meantime, if anyone has access to a 3D scanner capable of mapping block and sump..... Get in touch!

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Copyright Darrell Moores 2024