80 Years of the Flathead

I know we’re a tad late celebrating the 80th anniversary of the Ford Flathead (March 8, 1932), but I couldn’t pass up a chance to pay tribute to the engine that made Allards what they are. When most people think of Allards, they think of the “Cad-Allards” that were so dominant in the early 50’s. However, it was the Flathead that started the legend.

As a Ford repair depot during the War, Sydney had easy access to the simple, affordable, and powerful Flathead. The company primarily had access to the 21 stud flathead, which was by no means powerful compared to today’s standards, but it held its own in the 30’s & 40’s. The 21 stud Flathead (blue paint) has a displacement of 221 ci (3.622cc) that produces a mighty 85 bhp with 6.3:1 compression. For performance models, Allard also had access to the 24 stud Mercury Flathead (light green paint), with a displacement of 239 ci (3.917cc) at the same compression giving 95 bhp. 10 bhp may not be much of a difference, but what set the 24 stud apart was its’ ability to be modified.

Rather than going on about how amazing the flathead is, we feel it’s best to share the words of Tom Lush, Sydney’s personal assistant on the Flathead and how it was used by the ‘Company’. The following text is from Tom Lush’s book, “The Allard Story”:


Even at this early stage in the Company's history, the lack of a suitable power unit had begun to cast the shadow that stayed with Allard production until the end. Condemned through lack of alternatives to the obsolescent 3,622 cc Ford V-8 with its quoted 85 bhp, the cars were always lacking the performance to match their design, and this was particularly critical in the case of the J1 models, which were selling as competition cars.

Fortunately, the Company had purchased a batch of American built Mercury units (which had a slightly better output of 95 bhp from their 3,917 cc) from the Ministry stock at Hugon Road, and 12 of these were allocated to the J1 range.

The units were sent over to the engine shop in the Ford depot at Acre Lane and stripped right down. The cylinder blocks were bored-out to give a capacity of almost 4 litres and the heads machined to give the highest compression ratio possible, which was still only 7: 1 due to the limits imposed by lack of clearance over the valve heads. Although the American tuning market could offer all types of special camshafts and other equipment developed over the years for the flathead engine, stringent import restrictions made it impossible to obtain any of this, and for British customers they had to remain tantalizing catalogue items. The Mercury’s, therefore apart from the increase in capacity and compression, and the application of a specialized copperizing process to the cylinder-heads claimed to give a slight improvement in performance on the dismal low-octane Pool petrol, had to remain in near-standard form. The engines were reassembled with the external nuts and washers and petrol piping all chromed, and these, set off against the ‘copper’ cylinder-heads, gave almost a show finish to the mundane side-valve units.

Pages 61-62

Another instance of this policy control arose over the supply of the V8 engines. Production of the basic engine at Dagenham was divided into two categories; those for the Pilot assembly line were fitted with six-volt equipment and single-sheave water pump pulleys, while those for commercial vehicles or industrial use were 12-volt, and had heavy-duty double-sheave pulleys for twin belt drive to the dynamo and fan. As the Allards used a 12-volt system they had to accept the industrial engines, and either make up chrome-plated covers to hide the unused sheave on the pulleys (which looked extremely ugly if left exposed) or exchange the complete pump assemblies for the single-pulley car type. Requests to Ford's to fit the latter when assembling the engines fell on deaf ears; the production schedule said double pulleys would be used so double pulleys were used, even though the single types were probably being fitted On the next assembly line. This situation continued until the Pilot was replaced by the Consul and Zephyr models in 1950, after which the engines came with single-belt drive, although the dynamo still retained the double pulley.

Page 87

At Park Hill the general layout of the new chassis had been agreed and of the jigs was modified to the new design so that the prototype frame could be started. Unfortunately, no suitable engine was available, and with the rigid import restrictions then in force it was impossible to purchase any of the American specialized equipment for the Ford flathead V8, although in correspondence with friends in the United States it was suggested that followed their lead by ‘boring and stroking’ the 3,917 cc (239ci) Mercury unit.

This fairly simple operation involved increasing the bore size by 1/8”, and regrinding the big-end journals down to the Dagenham built 30 hp crank size, but offset to their original centerline to give an increase of 1/8” in the stroke, thus bringing the capacity up to 4,375 cc (267ci). These engines were broadly described as the 4 ¼ litre units and as the stores had several ex-WD Mercury’s in stock, and more were being released from government sources, the supply of these presented no difficulty, and a dozen were sent over to the Adlards Ford depot for this work to be carried out.

At the same time drawings and patterns were put in hand for the production of aluminium cylinder-heads and dual-carburetor inlet manifolds based on the American Edelbrock design [inlet manifolds were actually Eddie Meyers’ – Ed], one example of each having been sent individually to Sydney and myself as ‘personal gifts’, thus only bending rather than breaking the import regulations.

With these modifications an increase in power to 115 bhp could be anticipated, although the constricted exhaust ports of the front and rear cylinders would promote excessive water temperature when the engine was kept at full throttle for any length of time, as we knew from bitter experience with the pre-war cars.

Page 96

....and don't even get us started on the Ardun...