We here present further information concerning these cars supplementing the notes in our May issue.
When we published F. W. Ellis’s article on the Bamford & Martin Astons in the May issue, we certainly “started something” – for additional information came in and was published in “Rumblings” last month, and now, yet more is to hand, which we have no compunction in printing for these cars are amongst the most exclusive of British vintage sports models.
In last month’s issue we said that the twin o.h.c. Aston-Martin engine exhibited at Olympia in 1925 was designed by the Hon. Geoffrey Benson and used in Humphrey Cook’s 1925 200 mile race car. We have since had a letter from John Benson, now in N. Wales, in which he kindly gives us the true facts. He designed this engine just before Bamford and Martin Ltd. went into liquidation, and consequently only one engine was made. This he used himself in a 4-seater side-valve type Aston-Martin, covering 125,000 miles without as much as touching the main or big-end bearings. This engine had two valves per cylinder, of 45 mm. diameter and set at 90º. The sparking plug entered the combustion space between the valves but was masked in a recess having a communicating hole of approximately 5 mm. diameter. The two camshafts and the auxiliaries were driven by a train of gears at the front of the engine, and a vernier gave 1/2º steps in the timing, which really served no practical purpose. The cylinder head was detachable, and the compression-ratio about 5.6 to 1, the engine peaking at about 3,300 r.p.m. The cams were of gentle tangential shape, as the engine was intended to be blown; as stated, it proved wonderfully reliable and in the whole of its life damaged only one valve, the guides never needing replacement, although the tappets suffered when more violent camshafts were experimented with. The tappets, incidentally, operated via “jam-pots” and had shim adjustment.
Cooling and lubrication systems were the subject of very careful design. No fan was used and the bulk of the cooling water was delivered to an internal manifold immediately below the exhaust ports, the remainder passing between the jackets and up under the inlet ports. This proved highly satisfactory, but it is of interest that when an experimental head was put on to a s.v. crankcase and used in a fast motor-boat, distortion resulted, so effectively did the flow of stone cold water do its work. In a car, of course, such extremes of temperature were not experienced. Big-end and main bearings were lubricated at 60-lb./sq. in. pressure and the camshafts, valve gear and timing gears at 12 lb./sq. in., and there was 1 3/4 galls. of oil in circulation. Mr. Benson does not tell us whether his engine went first into Humphrey Cook’s ill-fated racing car, but he ran it in the 4-seater car until 1937. It pulled gear-ratios of approximately 3.5, 4.5, 6.5 and 9.2 to 1, and was good for about 85 m.p.h., the speed being much the same in top or third ratios. The chassis proved well up to these speeds in respect of road-holding and handling, but the extra power output made itself felt in the form of sheared differential bolts and clutch-shaft couplings – which, however, were standard s.v. parts. In 1937 the touring body was replaced by a single-seater and the engine was supercharged – no doubt our allusion to Mr. Benson’s experiments with a Zoller compressor on a 16-valve engine should, in reality, refer to this experiment on his own 8-valve car. As he was called abroad rather unexpectedly he had reluctantly to dispose of the car to a London garage before much was done, but he recalls getting 100 m.p.h. in third gear in “an astonishingly short space.”
Shortly after these interesting facts were given to us (which, incidentally, should do much to dispose of current rumours of blown 100 m.p.h. side-valve Aston-Martins) we were very kindly presented by Mr. Houldsworth who came all the way down from Harrogate to attend the July 750 Club meeting, with some further data about the standard Bamford & Martin productions. This takes the form of a catalogue of the s.v. cars and reprints of The Autocar and The Motor road tests, literature which we value very highly. The Motor had the car first (it was, we believe, the very first production model – Reg. No. AM270 – later illustrated in The Brooklands Gazette) and reported on it in May, 1921. Starting at midnight one Friday they motored almost continuously until 7 p.m. on the Saturday evening, and then started for home at 9.30 a.m. on the Sunday, getting in about 7 p.m., during which time they got from London to Holyhead and back, a distance of 625 miles. The return run of 275 miles was done at a 33 m.p.h. average, and the Aston gave 31 1/4 m.p.g. On Monday the sump was topped up, the plugs changed and the Houdaille shock-absorbers filled, and the car was taken to Brooklands, where it did a lap, two up, at 65 m.p.h., so that the genuine maximum speed was set at around 72 m.p.h. in touring trim. The engine was reported to run smoothly at upwards of 4,000 r.p.m. and gave 24, 40 and 55 m.p.h. respectively on the indirect gears. Top gear was given as 3.75 to 1. In the course of the test Alms Hill was climbed at never less than 15 m.p.h., and the car did not boil in climbing BwIch-y-Groes.
The Autocar reported on the same car in October, 1921, and had undertaken a test embracing a long Continental run, which we suspect was suggested by Lionel Martin himself. After 12,000 miles, including some competition work, the block had not been lifted, but 69 m.p.h was attained and one stretch of 158.4 miles was covered at slightly over 40 m.p.h. without really pushing the car. In this country the Aston was driven to Bridgwater and Sidmouth and back to London, and climbed Salcombe Hill easily, while Chard called for second as the lowest gear needed. Taken to Brooklands, still without a de-coke, this 4-seater lapped at 68.98 m.p.h. The top gears were now quoted as 3.73, 4.87, 6.9 and 13.2 to 1. The weight was 14 cwt. 3 qrs. 7 lbs. without passengers, the tyres 710 x 90 mm, and the wheelbase and track 8 ft. 7 1/2 in. and 4 ft. respectively. Fuel consumption was 32 to 35 m.p.g. This was the experimental car, and it was said that engine, gearbox and exhaust were noisy, the oil pump drive liable to chatter, and the alloy body to flex and crackle. It is interesting that there were said to be four cars in existence in October, 1921, when the price was given as £850, and the production programme then laid down sanctioned only 100 cars.
Mr. Ellis dealt so comprehensively with these cars that the catalogue, which is undated, tells us little that is new, although it reminds us that drilled connecting rods were a feature of the original engines. That the Aston-Martin appeared in 1914 is confirmed, and it was announced that a sporting model was in course of preparation, similar to the standard chassis, but lightened by elimination of starter, battery. etc., and with tuned engine and close-ratio gearbox. The cars were guaranteed for a year and, furthermore, the ordinary model was guaranteed to lap Brooklands with driver and one passenger at a minimum of 65 m.p.h., carrying open 2 or 3-seater body, electric lighting and starting, hood, screen and spare wheel. We like the statement: – “It is well understood that this average speed entails a maximum in excess of 70 m.p.h., but we guarantee the lap speed instead of the maximum as being, in our opinion, more capable of being checked by those interested.” We like, also, the statement: – “A starting handle is provided for testing compression, etc., but starting is effected by an electric motor mounted on the engine and driving by positive gearing to the flywheel.” 32-37 m.p.g. of fuel and 1,000 m.p.g. of oil was claimed. The gearbox mounting was very reminiscent of Bugatti practice. It seems that originally coil ignition could be supplied, but alterations to the catalogue in Houldsworth’s father’s handwriting suggest that this never came about, and also that the wheelbase was increased to 8 ft. 9in., the price reduced from £850 to £695 (The Motor quoted about £700 complete) and that Claudel and Cox Atmos carburetters were never fitted, although S.U., Zenith or White & Poppe were standardised. The back-axle ratio could be 3.5, 3.73, 4.0 or 4.5 to 1, to choice. Curiously, the catalogue contains no address, but it is worth recording that the Bamford & Martin Aston-Martin was made at 53, Abingdon Road, Kensington. We are indebted to Mr. Houldsworth for providing this additional data about the prototype and to Mr. Benson for information about his interesting “one-off” twin o.h.c. 8-valve engine. No wonder competition amongst connoisseurs to acquire the few remaining examples of these classic cars is so intense.