Recipe for a 70-m.p.h. "Chummy" Austin Seven
In the not so distant but now, all but forgotten past, George Chaplin had considerable success in trials and club speed events at Brooklands with a somewhat special Austin Seven tourer of 1924 vintage, known, for an unpublishable reason, as “Mr. Flea.” There is nothing especially remarkable in that, except that for a touring-bodied, unblown Austin Seven, “Mr. Flea” was inordinately fast — such as covering nearly 60 miles in an hour during an M.C.C. high speed trial at Brooklands. Moreover, the car was used on the road and was decently reliable, only once breaking its crankshaft (1 1/8 in. of course) and once running a big-end, both times during trials. Being curious to know how this was done we called on Mr. Chaplin.
He opened his scrap-book and there was “Mr. Flea” — an ordinary, early “Chummy” Austin Seven, rather startlingly finished in Chaplin’s coaching colours of yellow and brown, with strip front wings reminiscent, if we may be pardoned the comparison, with those on old “No. 7” Bentley, no running-boards, but with its back wings intact. The screen was composed of two top panels, arranged so that one acted as bottom panel and both would open out. The driver sat lower than normal, and, of course, had fitted a bonnet strap. Two aero screens inside the standard screen frame came later, justified by the increasing speed.
Having tuned motor-cycles, particularly a Rudge, Chaplin took up car competitions with an A.B.C. This gave so much expensive trouble he sought a cheap utility car, and about 1926-7 bought the Austin, hoping for a quiet life. But the urge was too great, and he went in for competitions. Its successes are imposing. We find it first in the 1928 M.C.C. High Speed Trial, doing 51.3 miles in the hour and 18 laps instead of the 15 minimum to collect a gold medal. In a J.C.C. Night Trial a silver cup for best performance with Miss Sander’s Austin came to hand and a gold medal in the “Exeter” followed. Chaplin took a Singer “Porlock” through the “Land’s End” of 1929, then the “Chummy” did 17 laps in the hour to gain a “gold” in the M.C.C. High Speed dice. In the J.C.C. Members’ Day trial over a stiff “road” course at Brooklands the Austin took another “gold.” In 1930 another High Speed Trial “gold” came home in the J.C.C. event, “Mr. Flea” also finishing second in a one-lap race, doing the standing lap in 2 min. 51.4 sec. Incidentally, “Mrs. Flea,” Chaplin’s 1928 “Chummy,” ran at this meeting, in the hands of Latham-Booth, but was disqualified. Chaplin himself drove “Mrs. Flea” at the Brighton and Hove Brooklands meeting, but returned to the faster “Mr. Flea” for the M.C.C. event, covering 20 laps in the hour (55.96 m.p.h.). A silver medal in the M.C.C. Derbyshire Sporting Trial followed. Apart from this two other “golds” in M.C.C. classic trials and sundry lesser awards should be mentioned. Chaplin had a break in the early part of 1931, to organise a team of amateur-owned and driven “Ulster” Austins in the “Double Twelve” — but that is another story.
The “Chummy,” now completely stripped, came out again for the 1931 Relay G.P. and, the team’s “B” car retiring at once, covered 80 laps before the race ended. That year, also, the Austin did 59.49 miles in the hour on “M.C.C. day,” and 21 laps in the Brighton and Hove High Speed Trial, 17 only qualifying drivers for a “gold.” 1932 produced a special award in the J.C.C. “hour” and two consecutive laps in the Relay Race at 73.24 m.p.h., one lap at 73.78 m.p.h. and the standing lap in 2 min. 40 sec. That was about the last competitive appearance of “Mr. Flea,” for Chaplin sold her to a garage at Cheam when he acquired his 1931 orange blown “T.T.” Austin Seven in 1933.
What, then, did Chaplin do to achieve these results? The answer, as so often before, is: nothing startling; mainly careful assembly and low overall weight. The engine was a magneto-ignition unit with the original small crankshaft. Chaplin cut off flush the ends of all the valve guides and fitted Terry “Aero” double valve springs. The tiny updraught Zenith carburetter he threw away, substituting a horizontal 26-mm. Solex on a buffer-ended, straight manifold of approximately 1 1/16-in. internal diameter. Standard Austin valves, tappets and pistons were retained but the engine was carefully assembled. As far as Chaplin can recall he used a 105 main jet for speed and a 95 for touring, with a 60 compensator, and ran on Vacuum castor oil and 50/50 petrol-benzole fuel. No advantage being apparent in fancy crankshafts, Chaplin used a standard one, but Geoffrey Taylor sent down a couple of Alta alloy heads, so these were tried out and retained, that having inclined plugs over the exhaust valves apparently giving the better results. It gave a compression ratio of 6.2 to 1. Champion R1 plugs, or sometimes K.L.G.246, gave every satisfaction. For a long time the button oil-indicator was deemed adequate, but eventually a gauge reading to 10 lb./sq. in. was obtained from a Morris and this showed 4 lb./sq. in. on castor oil and 2 1/2 lb./sq. in. on mineral oils. A camshaft from a blown Austin was fitted in the later stages. The usual B.L.I.C. magneto of the period was retained and, also as usual, threw its rotor away on occasion. The chassis had the normal 3-speed gearbox and 4.9-to-1 back axle, but 26 x 8-in. tyres gave a high ratio and were retained for what Chaplin refers to as “flattery,” low-pressure tyres lowering the ratio slightly, for trials. The early square-door body was of aluminium and the car weighed in the region of 6 cwt.
That is about all Chaplin did to get his performance. A lap at over 70 m.p.h. means at least 80 m.p.h. down the straight, and while you would not get this speed very often on the road, a “Chummy” Austin Seven able to do an easy 65 and cruise at least 15 m.p.h. faster than any of the many aged “Chummy” models still on the road, is, even in 1946, a rather happy thought. Perhaps that is why we went to see George Chaplin. You may retort that an early Austin Seven would he quite unmanageable at such velocities. Chaplin thought the same, and even before hotting-up his car he attended to its chassis. Two large friction shock-absorbers from a breaker’s were somehow hung on the frame to damp the rear axle movements and proper castor action was obtained by packing out the front-axle radius arms with 1/8 to 1/4-in. thick D-washers, so tilting the king pins. An extra star washer was employed for the front damper and the steering steadied by means of one of the proprietary friction dampers then on the market. Later the chassis was wire-braced, aircraft fashion. That, then, is the story of “Mr. Flea” the idea of building a replica may, or may not, appeal to you.
Incidentally, apart from his Austin activities, Chaplin successfully drove an A.C. Six in the 1927 M.C.C. High Speed Trial, took a Ford V8 through the 1933 R.A.C. Rally, an S.S.I. through the 1934 Rally, an A.C. through the 1935 Rally, and drove an L.M.B. Ford V8 in one J.C.C. High Speed Trial. But he says he got the greatest fun and excitement from the 1924 Austin “Chummy.” We can well believe it.