Were it still available today, the SLIM would seem to be an ideal snake for those who employ diets and exercise to achieve a slim figure, especially as modern printers render the name without stops! The letters really stand for Société Lyonnaise de l’Industrie Mechanique et Autos Pilain.
This company began car production in 1920, and endured until 1929. It might well have appealed to the flappers of the vintage era, with flat chests and absence of waistline beneath their cloche hats. However, there is more to it than that. In mechanical terms the SLIM was a very advanced car.
The first occasion on which British motorists heard of the SLIM would have been when they were wandering round the 1920 London Motor Show, and saw that Ferrous and McCracken Ltd had imported one.
There in the White City overflow to this well-supported Show was a 3.8-litre 19/40hp four-cylinder SLIM, and the remarkable thing about it was the use its designer had made of compressed air to cope with the chores facing drivers in those days. On this unusual French car, pneumatics looked after the engine-starting and braking, and even operated the jacking system, blew up the tyres when necessary, and sounded the horn!
This was achieved by having two large compressed-air cylinders mounted towards the rear of the chassis (duplicated for safety), fed by a engine-driven four-cylinder pump. At a time when starters were not always dependable, punctures were rife, and there were problems associated with the operation and proper compensation of front-wheel brakes (with which the SLIM was equipped) by mechanical means, the obsession with pneumatics was understandable.
Moreover, the SLIM had an impressive-looking 90mm x 150mm overhead-camshaft engine, a plate clutch, a unit four-speed gearbox and half-elliptic springing all round. It ran on disc wheels shod with 895 x 130 Michelin tyres and had Bleriot electric lighting. Only a chassis was exhibited at the 1920 Show and no price was quoted. It is interesting that the rear brakes were applied before the front brakes were energised by the ingenious compressed-air system, in conformity with prevailing ideas of adopting FWB cautiously — a lead followed later by Rolls-Royce.
Practical as the SLIM pneumatics may have been, English buyers did not trust them and the make was not at the 1921 London Show. It had, however, appeared at the Paris Salon, with a polished bird’s-eye wooden instrument panel. Also, in order to conform to the trend towards positively-driven dynamos, this component was made as part of the propeller shaft — the armature turning with it, the field coils surrounding it.
If the compressed-air 19/40hp SLIM was not over-welcomed, the engineers working on this successor to the Pilain refused to give up and follow conventional paths. By 1922 they had come up with a new 11.4hp SLIM light car, of 65mm x 130mm (1725cc), which had its own unusual features.
For instance, the propshaft-driven dynamo, a large Paris-Rhone component which also acted as the starter, was retained, which may be why a De Dion rear axle was used, to get the gearbox out of the way. There was no propshaft from gearbox to final-drive — more of an extended clutch-shaft. The adoption of this De Dion rear suspension was facilitated by Pilain giving SLIM a licence to use its axle.
This De Dion axle was sprung on a combination of normal semi-elliptic and four quarter-elliptic springs (two each side) arranged as three-quarter elliptics, although normal half-elliptics sufficed at the front. There was again four-wheel braking, now cable operated, but possessing ingenious adjustments for the shoes in the front drums, a vernier setting for the cam-lever, a means of taking up the cables, and a left-and-right adjustment at the pedal. The lever applied cast-iron shoes in steel brake drums on the back wheels, and the pedal operated on all four wheels via the same rear shoes.
The engine was also unusual, for although it was of push-rod ohv type there were two camshafts, one on each side down in the crankcase, with tappet adjustment at the base of the push-rods and rocker actuation of very small vertical overhead valves — four per cylinder. So here was an early sixteen-valve engine with valve-gear not unlike that of Riley and Dorman; except that the valves were not inclined to provide hemi-heads. One push rod served a pair of valves. The SLIM engine was also unusual for a small power unit in having pump-cooling, the pump being driven from an extension of the magneto shaft.
LC Engine and Supplies Ltd of Westminster had now taken over the gamble of selling SLIMs in this country, pricing the new 11.4hp chassis at £550. Advanced it was, but the owner had to oil the valve-gear periodically by hand, for which holes with feed-pipes were provided in the valve cover.
For 1923 the engine was given a 3mm-larger bore, making the swept volume 1888cc; later a 2.3-litre sixteen-valve model and a 80-bore 2.6-litre were introduced. The new concessionaires had a real try, showing two chassis and a two-seater at White City in 1922; they asked £515 for the 11.9 chassis, £675 for the 15hp, and a rather high £600 for the two-seater light car. The slogan was ‘Four” — four cylinders, speeds, valves and brakes. The SLIM was at Olympia in 1923, when LCE exhibited a purple touring body on the 12hp 57 mph chassis. In keeping with the trend to have a sports model in the catalogue, there was also an Albany boat-tailed three-seater with flared mudguards on the 2.4-litre chassis, 70 mph was claimed from the tuned engine, but were there any takers, at £725?
Nevertheless, them were British customers, who became very fond of their SLIMs. For example, a Mr Farquharson purchased a 12hp model at the 1922 Show, drove it 23,000 miles and then bought a 15hp model at the 1923 Show after trying the six other cars on his shortlist. The smaller SLIM had excellent 4WB and was able to get down River Hill in Sevenoaks in Christmas snow when 30 or 40 other cars and lorries could not. The car gave 28 mpg in traffic, and the only trouble was a broken front spring. The unusual dynamo was especially efficient. As with other French cars, third gear had to be used quite frequently, but less so on the 15hp version.
Another owner of a 12hp model agreed that the springing was too lively, but this was cured when Hartford shock-absorbers were fitted on later cars. He obtained 62 mph and 32 mpg.
Wilfred Boilton, who had invested in a 15hp model with a 25 cwt all-weather body, was another satisfied SLIMmer. After 7000 miles he had just had his first puncture, the tyres looking good for 11,000 miles. He got 24.5 mpg on hard going in Scotland, 26 mpg elsewhere, and 50-70 mph in top gear. He spoke of the very efficient starter and good brakes, those on the front wheels having no effect on the steering, and the special rear springing obviated roll on corners.
The SLIM was exhibited again at Olympia in 1924 in much the same form as before. The enlarged 12hp 1888cc model was designated the 12/40, the chassis price down to £315, and there was a Super-Sports model with twin Solex carburetters, whereas the smaller car had a single Lacharnay unit. Sales were perhaps restricted because only these two chassis were displayed, and it was usually only on much larger cars that clients consulted their coachbuilders.
The SLIM leant towards being a sporting car, and back in 1923 the agents had imported from France a pointed-tail 12hp model with outside exhaust pipe and fan-tail, priced at £750. Alas, in spite of ingenious design, it had all fallen by the wayside long before the depression could be blamed. WB