The Pre-War Car Thread

[lesapandre]

Humber Hawk - part of the ultra-conservative Rootes Group was a flathead until June 1954.

[wuvvum]

The Ford 100E was sidevalve right up until the end of production in 1959.  I think that was the last British car to use a sidevalve engine, unless you count the Reliant Regal, which wasn't technically a car.

[Mr Pastry]

2 minutes ago, wuvvum said:

The Ford 100E was sidevalve right up until the end of production in 1959.  I think that was the last British car to use a sidevalve engine, unless you count the Reliant Regal, which wasn't technically a car.

100E went on a bit longer than that, 1962 iirc.   Let down by its 3 speed gearbox, rather than the engine.

[SiC]

I wonder if the Axiam microcars with their lawnmower derived engine were flat heads on their older models and made them one of the last?

[RayMK]

18 minutes ago, SiC said:

I wonder if the Axiam microcars with their lawnmower derived engine were flat heads on their older models and made them one of the last?

I'm not aware of any Aixams having a flathead engine.  They came on the scene in 1987 with, as you said, an agricultural diesel engine by Kubota . They were ohv.  As far as I recall, the petrol versions came even later - in the UK at least, and were an overhead cam design (Lombardini).  Cheating a bit, but the Saab  96 2 stroke was sold in the UK up to 1967.  Its head was flat.  Similarly,  Wartburg's 2 stroke saloon sold in the UK until 1976, but no valves in the heads of either of these 3 cylinder units 😁.   Reliant phased out the flathead Austin 7 derived sidevalve engine in 1962 in the Regal MKVI.   

Dad's 1954 Hillman Minx was a flat head 4.  It struggled to reach an indicated 70mph and sounded as if it would self destruct.  50mph was its usual cruising speed.    

[Knotty Ash Towers]

1 hour ago, wuvvum said:

The Ford 100E was sidevalve right up until the end of production in 1959.  I think that was the last British car to use a sidevalve engine, unless you count the Reliant Regal, which wasn't technically a car.

As an aside, Ford were selling the KA with pushrod engines until 2002, rather dated by then, I would imagine.

[martc]

Are 'Heron' heads 'flat' heads? If they are then Moto Morini motorbikes had them well into the 1980's, the Ford Essexes and Kents, Jaguar V12, the Alfasud boxer, Rover 2000, Lamborghini  Urraco and various VW, Vovo  and Audi engines all had them.

But the winner is the Moto Guzzi small block engine, still in production has a heron head AND push rods.

[Momentary Lapse Of Reason]

1 hour ago, martc said:

Are 'Heron' heads 'flat' heads?

No.

 

[Mr Pastry]

Flathead, in American, refers to the outside bit.  A side valve head has combustion chambers, thus:

 

[Dyslexic Viking]

8 hours ago, wuvvum said:

Vauxhall were using OHV by then too.  And independent front suspension, and semi-monocoque construction.  GM were pretty ahead of their time before the war.

This is the engine in a 1934 Vauxhall Light 6 which just happens to be in my eBay watch list at the moment.  Not dissimilar in design.

I wonder if GM gave drawings of the Chevrolet stovebolt engine to Vauxhall and Opel and asked them to make their own copy in the size and other things that suited their market because the engines are very similar.

[wuvvum]

6 hours ago, Mr Pastry said:

100E went on a bit longer than that, 1962 iirc.   Let down by its 3 speed gearbox, rather than the engine.

You're right, the Popular continued for a couple of years after Prefect production ended and Anglia went OHV.  I've learned something today.

Having owned a 100E in Prefect form, the gearbox was the worst bit, but the engine was ridiculously thirsty for the performance* it gave.  I imagine the vacuum wipers were pretty dire too on models without a tank.

[High Jetter]

6 hours ago, wuvvum said:

unless you count the Reliant Regal, which wasn't technically a car.

Harsh.

[wuvvum]

7 hours ago, SiC said:

I wonder if the Axiam microcars with their lawnmower derived engine were flat heads on their older models and made them one of the last?

Were there any flathead diesels?  I would have thought the design of a sidevalve head would make it effectively impossible to obtain a high enough compression ratio for a diesel engine to function properly.

The older petrol-engined French microcars generally used 50cc 2-stroke moped engines, most often of Motobécane origin.

[artdjones]

2 hours ago, wuvvum said:

You're right, the Popular continued for a couple of years after Prefect production ended and Anglia went OHV.  I've learned something today.

Having owned a 100E in Prefect form, the gearbox was the worst bit, but the engine was ridiculously thirsty for the performance* it gave.  I imagine the vacuum wipers were pretty dire too on models without a tank.

The 100E was at least within touching distance of modernity apart from that gearbox and the vacuum wipers. 

The 103E Popular, which only stopped in production in 1959, had beam axles all round, and was based on the prewar Anglia. It had 6v electrics, rod brakes, and did without the luxury of two wipers, one being considered sufficient for the extremely frugal Popular owner. Who would definitely keep his change in a small purse.

Strangely, although Fords always had very basic base models to tempt the extreme mingebag who still had enough cash to splash on a new car, they never managed to make them economical on petrol, which rather negated the point. Even the MK1 Fiesta was pushed to get 30mpg, when equivalent French cars would do 35. And when the crude Motorcraft or Autolite carburettors wore, Fords could produce pretty awful figures. My 1.6 Mk 3 Cortina did 12mpg around town.

[Mr Pastry]

12 hours ago, Dyslexic Viking said:

I wonder if GM gave drawings of the Chevrolet stovebolt engine to Vauxhall and Opel and asked them to make their own copy in the size and other things that suited their market because the engines are very similar.

A lot of that sort of thing happened.  The English Ford side valve engines were designed in the USA, and were practically scaled-down Model A engines.  The Morris 8 - whole car, not just the engine - was very much based on the Ford Y type.  Slightly more recently the Ford Zephyr and Vauxhall Cresta straight 6s were similar, a complicated story but the same designers were involved in both.  And the BMC B series was inspired by a wartime Bedford truck engine, so there is a GM connection there as well.

 

[Mr Pastry]

10 hours ago, wuvvum said:

You're right, the Popular continued for a couple of years after Prefect production ended and Anglia went OHV.  I've learned something today.

Having owned a 100E in Prefect form, the gearbox was the worst bit, but the engine was ridiculously thirsty for the performance* it gave.  I imagine the vacuum wipers were pretty dire too on models without a tank.

The 100E bodyshell of course was used for the 107E Prefect, with the Anglia OHV engine.  One of my pals long ago had a 100E.  Another mate who considered himself an ace mechanic talked him into fitting an Anglia OHV engine, which they got from a breakers.   To be fair it was a good effort given their complete lack of experience.  It was a massive job, and they got it to fit without changing the crossmember, which wasn't supposed to happen.  The performance afterwards was no different, if anything slightly worse!

 

[wuvvum]

4 hours ago, Mr Pastry said:

The performance afterwards was no different, if anything slightly worse!

Did they fit the  4-speed 'box as well?  Although the 997cc 105E engine was slightly more powerful than the 1172cc sidevalve, I wouldn't imagine that it had the low-down torque needed to bridge the massive gap between second and third on the 100E gearbox.

[wuvvum]

12 hours ago, artdjones said:

The 103E Popular, which only stopped in production in 1959, had beam axles all round, and was based on the prewar Anglia. It had 6v electrics, rod brakes, and did without the luxury of two wipers, one being considered sufficient for the extremely frugal Popular owner.

Am I right in thinking that it also did without a water pump right up until the end of production?  Must have been the last car with thermo-siphon cooling?

[Mr Pastry]

11 minutes ago, wuvvum said:

Did they fit the  4-speed 'box as well?  Although the 997cc 105E engine was slightly more powerful than the 1172cc sidevalve, I wouldn't imagine that it had the low-down torque needed to bridge the massive gap between second and third on the 100E gearbox.

Yes they would have fitted the 4 speed box as well, the 3 speed would not fit the engine.  Don't know what they did about the gearbox mountings, which are very different.  Axle ratios were the same on both versions, I think.  Possibly just a dud engine!

[captain_70s]

4 hours ago, Mr Pastry said:

 The performance afterwards was no different, if anything slightly worse!

Looking at the performance recorded by period road tests there is barely any performance difference between the side valve and OHV.

A few seconds off a 30+ sec 0-60 time and a couple of mph extra top speed probably wouldn't be noticeable when peak torque and power is higher up in the rev range...

[Knotty Ash Towers]

12 hours ago, artdjones said:

The 100E was at least within touching distance of modernity apart from that gearbox and the vacuum wipers. 

The 103E Popular, which only stopped in production in 1959, had beam axles all round, and was based on the prewar Anglia. It had 6v electrics, rod brakes, and did without the luxury of two wipers, one being considered sufficient for the extremely frugal Popular owner. Who would definitely keep his change in a small purse.

Strangely, although Fords always had very basic base models to tempt the extreme mingebag who still had enough cash to splash on a new car, they never managed to make them economical on petrol, which rather negated the point. Even the MK1 Fiesta was pushed to get 30mpg, when equivalent French cars would do 35. And when the crude Motorcraft or Autolite carburettors wore, Fords could produce pretty awful figures. My 1.6 Mk 3 Cortina did 12mpg around town.

In 2018 had a MK 1 Focus 2.0 manual, which used to average 24 MPG. The best I ever managed out of it was 29 MPG on a run. I didn't keep it very long, as it was costing me £30 a week in petrol, which would be about £45 a week now...

[Metal Guru]

On 17/04/2026 at 16:04, Mr Pastry said:

100E went on a bit longer than that, 1962 iirc.   Let down by its 3 speed gearbox, rather than the engine.

My Dad had a 100E, bought new in 1963. I remember the gear box jammed quite regularly although only when stationary. 
 

[Metal Guru]

1 hour ago, Knotty Ash Towers said:

In 2018 had a MK 1 Focus 2.0 manual, which used to average 24 MPG. The best I ever managed out of it was 29 MPG on a run. I didn't keep it very long, as it was costing me £30 a week in petrol, which would be about £45 a week now...

That’s Impreza mpg!

[Dyslexic Viking]

I got to thinking about which vehicle from before or around the war was in production the longest?

It must be the original Dodge Power Wagon 1945-1978? It was based on the WW2 Dodge MC series and I believe it used the original flathead 6 cyl until the end. They are among the most robust and capable 4x4s ever made so one can see why they were in production for so long.

[artdjones]

3 hours ago, wuvvum said:

Am I right in thinking that it also did without a water pump right up until the end of production?  Must have been the last car with thermo-siphon cooling?

Yes, a water pump was a modern* refinement it did without. A friend's father had one in my very early youth (I was around 4), but then went over to 803cc Minors. One of the tightest people I ever knew.

[artdjones]

2 hours ago, Knotty Ash Towers said:

In 2018 had a MK 1, especially considering Focus 2.0 manual, which used to average 24 MPG. The best I ever managed out of it was 29 MPG on a run. I didn't keep it very long, as it was costing me £30 a week in petrol, which would be about £45 a week now...

Japanese or French used to be the way to go for good economy. Flat 4 air cooled VWs were pretty heavy on fuel especially considering their limited power output.

[Knotty Ash Towers]

45 minutes ago, Metal Guru said:

That’s Impreza mpg!

If it had been an automatic I could have understood the fuel consumption being that bad. It was actually marginally worse than the Lada Riva I had, despite having a bigger fuel tank.

[Mr Pastry]

AIUI the story is that Ford didn't have the development budget to put an OHV engine in the 100E, as the Mk1 Consul had been an expensive project.  So they designed a new side valve engine and 3 speed gearbox for it - not the same as the Upright Pop units, and not interchangeable.  Which seems a bit daft, as the Kent engine and 4 speed box for the 105E Anglia must have been on the way by then.  Perhaps internal politics came into it.

[artdjones]

1 hour ago, Mr Pastry said:

AIUI the story is that Ford didn't have the development budget to put an OHV engine in the 100E, as the Mk1 Consul had been an expensive project.  So they designed a new side valve engine and 3 speed gearbox for it - not the same as the Upright Pop units, and not interchangeable.  Which seems a bit daft, as the Kent engine and 4 speed box for the 105E Anglia must have been on the way by then.  Perhaps internal politics came into it.

That's the kind of stupid decision you get when accountants run things. 'We're a bit short in this budget period, so we'll make a decision that means we have to pay twice in the long term.'

The 100E was a good car spoiled by that decision. If it had been ohv and four speed the extra sales would have paid for the extra development costs.

[Rustyrotavator]

2 hours ago, artdjones said:

Must have been the last car with thermo-siphon cooling?

Trying to remember if my rear engine Skodas, with radiator  at the front , had water pumps.