Another Motoring Mystery
The Calthorpe Company of Birmingham, founded in 1902 and reformed in 1912, took part in pre-War road races and was represented at Brooklands in the nineteen-twenties. It built some quite acceptable small sports cars before and after the First World War. But soon after the Armistice it got into difficulties, according to Lord Montagu because of a series of complicated share deals.
The late George Hands had started the Calthorpe Company but left at this time to run the Palace Hotel at Torquay. He was also responsible for the Hands light car and returned around 1923 to try to resuscitate Calthorpe fortunes.
Any success that Calthorpe had had in recent times had been achieved mainly with the pre-war Calthorpe Minor and the post-war Sporting Calthorpe. But with fortunes at a low ebb, two new Models were announced for 1923, details of which were released at the end of September 1922. These were the 10/15 and 12/20 models. The former was merely an -improved version of the successful car, the 3-speed gearbox and ¼-elliptic back springs of which had given place to a new 4-speed gearbox and ½-elliptic back springs.
But the 12/20 was an entirely new car. My attention has been drawn to it recently, because the 1924 Calthorpe I own is nearly ready for the road again after running a big-end and this has made me keen to uncover what I can of Calthorpe’s history. I put an appeal in Motor Sport. This fell mainly on stony ground, except for the kindness of a reader in Hornchurch„ who sent me a 12/20 instruction book. Study of this very well-illustrated and detailed publication shows that my 12/20, which was first registered in May 1924, bears little resemblance to the car so enthusiastically described in this book.
A little research proved that the car thus described was, in fact, that introduced as a new model for the 1923 season. But a year later, by mid-September 1923, another version of the 12/20 Calthorpe was announced, a car which obviously superseded the previous model of this rating and which was shown at the Olympia Motor Show, ready for the 1924 season. My car follows the latter specification. Both have the classic dimensions for a 4-cylinder engine of 69 x 100 mm., giving a swept volume of 1,496 C.C. But there are some significant differences between these 1923 and 1924 12/20s.
The most obvious is that the earlier engine is depicted as having an aluminium water-dome over the side-by-side valves, which were under detachable valve caps, the head being integral with the cylinder blocks, whereas the later engine is of conventional side-valve layout with a detachable cylinder head held down by 15 studs. It seems logical to have abandoned the former idea because, apart from the cost of the alloy casting (which does not seem to have worried Calthorpe, who used quite elaborate castings of this material in their cars) the dome was no doubt a brute to remove alter its eight holding-down stud and the stud securing the water outlet pipe had corroded, and to withdraw the valves it and eight valve caps had to be removed, and new jointing made when these were replaced, whereas on the later engine only the head had to be lifted for access.’ to the valves, and the C.& A. gasket replaced thereafter. On the “water-dome”-engine the sparking plugs were situated horizontally below it on the n/s but in the conventional power unit they entered the head vertically.
Other subtle differences existed. For instance, although all components, including the dynamo. were positively driven, On the 1923 car the magneto was on the n/s and the water pump on the o/s of the cross-shaft which drove them by chain and skew-gears from the crankshaft. For 1924 these were reversed and changes made to the front casing carrying the drive. The earlier Calthorpe was quoted, in the aforesaid book, as having “been carefully thought out, so as to allow the use of ordinary spanners for tappet adjustment,” but by 1924 this advantage had been lost, the person who has been reassembling my engine telling me that the split tappets have a barrel section that necessitates employing a special thin spanner as well as two ordinary spanners.
The oil filler was on opposite sides in these two engines, the inlet manifolding was different, and whereas for 1924 the dynamo was driven from the nose of the crankshaft, in the 1923 car it Was driven from the water-pump drive, being mounted in-line with the side of the crankcase, with the starter behind it, both on the o/s. The starter had an inaccessible location under the bell-housing and half within it, for which rigid mounting was claimed as an advantage, on the 1944 version of this Calthorpe 12/20.
Continuing to note differences between these two cars introduced only a year apart, the first version had a Single-plate clutch, described as “entirely new, self-contained in every respect, extremely sweet and efficient.” This notwithstanding, by 1924 it had been changed for a multi-plate clutch, having nine plates. The 1923 car used a big tubular gross-member in front of the gearbox but my 12/20 hadn’t got this. The separate gearbox of the early car had a square-shaped casing but a barrel-shaped unit gearbox came later, devoid of the little leg; cast on it for supporting it when out of the car, although these appear on the engine sump of my car. But the sump is of different shape, the early one being square, so that four of these neat little legs, so thoughtfully provided to support it on the work-bench, arc required, whereas the later sump Is inclined and needs only two legs at the back; it seems that the early one holds 9 pints, the later one 8 pints of oil, but one account says 10 pints. Incidentally, the makers recommended Calthorpe Filtrate, Vacuum BB, Price’s or Double Shell, and seemed very content with 1,500 m.p.g.
The “water-dome” cars apparently had 4-shoe brakes (r.w.b.) but my car has 2-shoe anchors. The early instruction book speaks with enormous pride of the front axle: “Every owner of a Calthorpe will be justifiably proud of his front-axle… we venture to state that there is no front axle of any light car made with that care bestowed upon it, as instanced in the new 12/20-h.p. Calthorpe.” The steering gear was also “manufactured in our own works.” After which, I am distraught to have to admit that I do not have this fine front axle because it has been replaced at some time on my car by an axle from a Morris Oxford, in order to obtain the advantages of front-wheel-brakes, which Calthorpe did not announce until late in 1925.
Yet, these differences apart, there is evidence that both engines followed regular Calthorpe practice and are likely to have been designed by the same designer. For example, the wide crankcase which rests on the Chassis side members, Bugatti fashion, the ribbed exhaust manifold, the rather awkward capped dip-stick, the tubular steel con.-rods with taper-pins securing the gudgeon-pins, the split tappets (with the aforesaid difference), the chain timing gear and the bell housing and flywheel pit are similar on both engines. The cover plate on the end of the crankcase through “which the crankshaft is inserted, as on Miller racing engines, is also common to both power units. The formation of the lubrication scoops for the big-ends, and the steering box, are also similar on both cars; the steering drag-link identical. The new type of oil-pump, exposed at the front of the engine, was used for both engines. Changes such as from a Cox-Atmos to a Smiths or Zenith carburetter, from M.L. to another make of magneto, and the underslinging of the back springs on the 1924 ears can be set down as normal development.
But a mystery remains, inasmuch as, with the Calthorpe Company in a bad way and Mr. Hands intent on saving it, why on earth did he permit the design to be thus changed, fairly drastically, in the space of a year or less?
I have heard rumours that he called in Davidson of Lagonda to design the 12/20 engine and then Hugh Rose, who had come from Sunbeam’s. Is it possible that the former was responsible for the 1923 engine and that Rose simplified a too-complicated design? If so, why did he find it necessary to transpose the magneto and water pump, make a new front casing, and so on?
The solution may be that the car announced in September 1922 was never put into production. One at least must have been made, because the illustrations in the lavish instruction book are photographs, and a photograph of at least the engine appeared in contemporary Press descriptions. Moreover, a stripped chassis and a coupe (priced at 410 gns.) were shown at Olympia in November 1922, and the latter was presumably the car road-tested by The Autocar in May 1923, when it blotted its copybook on the Worcestershire hills with clutch slip, which may be why the clutch was changed on the 1924 version. However, one report spoke of a 3-speed gearbox on the Show chassis, so it is possible that parts of the new model had not been made by that time, giving strength to a suspicion that in the instruction book the gearbox casing depicted may have been Made of Wood!
Certainly by the following September, when the simplified 12/20 Calthorpe was announced, photographs seem to have been more readily available. Moreover, while after 1923 quite a selection of used 12/20 Cars were to be found in the small advertisement columns of the motor papers, I can find very few before this. So the inference seems to be that the new model announced for 1923 never got off the ground; that it was probably a Calthorpe which never was. I wonder if any reader can refute this; by recalling ownership of a “water-dome” 12/20? One feels that Mr. Hands was faced with troublesome difficulties at the time this model was adopted, in spite of the good advice his instruction book gave to potential owners, who were requested to read it “no matter how expert you may be.” You were, for instance, advised to start the engine by hand once a week to verify its condition (I hope I remember to do this), to keep the reverse catch in its slot when reverse wasn’t in use and, in spite of that impeccable front axle, not to bump the kerb. It seems that Calthorpe may have been forsaking their sporting reputation at this time, for they advised: “Don’t accelerate violently or jam your brakes on hard. These amusing little habits should be confined to the sporting fraternity, who are prepared to pay for them.”
This 26-page book is a minor mystery in itself, because why was it prepared if the car it covered was unlikely to get into production? Calthorpe apparently liked these elaborate owners’ manuals, because in December 1923 they announced that such a book was available for the 12/20. One hopes it applied to the revised version!
The new 12/20 did not save the Company. At the 1924 Olympia Show a chassis, a two-seater, two tourers and a cabriolet were exhibited, whereas only a solitary 10/15 was shown. By September 1924 Mr. Hands had taken over full control of the again reconstructed Company and the 3-speed ¼-elliptically sprung 10/20 model was revived, the 12/20 was continued with minor modifications and a new overhead camshaft 1,860-c.c. 6-cylinder model was introduced (whose engine was this?), rather curiously with a 3-speed gearbox, but having f.w.b. Cecil Clutton, a past-President of the V.S.C.C., has pointed to the frequent demise of small firms that tried to market 6-cylinder cars and the fate of the Calthorpe Company is -a pertinent example. This 6-cylinder 15/45 Calthorpe had the camshaft driven by a vertical shaft at the front of the engine, wire wheels (bolt on) and cost £395 as a tourer—but I should be surprised to hear that anyone bought one.
For 1926 the 10/15 was increased in size to 65 too mm. and called the 10/20, the 12/20 was as before, and the 15/45 six now had a 4-speed gearbox, longer wheelbase and other changes. Four-wheel brakes were at last introduced. A grab at survival which does not seem to have had any logic behind it was the announcement of a de luxe edition of the 12/20, sometimes, I believe, called a 12/25, with 69 x 115 mm, (1,720 c.c.) engine strengthened internally and with full pressure lubrication—another Calthorpe that probably was never made… There were no Calthorpe exhibits at the 1926 Show.
It is rather interesting to reflect on what these comparatively expensive small cars had to offer in competition with mass-produced makes. When the 12/20 Calthorpe was introduced in 1923 it was priced at £285 in two-seater form, when the Clyno and the Morris-Cowley cost £198.. For 1925 the Calthorpe chassis cost £260, the Clyno chassis £100 less, the Morris-Cowley £115 less. But cars like the Calthorpe could boast of elaborate light-alloy castings and, apart from the 12/20’s individualities of inclined valves in turbulence-promoting combustion chambers, very generous water passages, positively-driven dynamo, large ports, tubular con.-rods, external bronze-bodied oil-pump and breathers in the engine bearer arms to prevent oil vapour soiling the engine, there was the 4-speed r.h.-controlled gearbox (the gears of which, like those of the back axle, were made of B.N.D. and M.N.O. air-hardened nickel-chrome steel) when Cheaper cars had but three speeds; with central lever on the Morris. The Calthorpe had excellent treatment of details, such as a rigidly mounted steering-box with full gear ‘wheel and splined adjustment for the drop-arm, eccentrically-mounted adjustable clutch pedal (not just a pedal stem secured in a clamp), gear-selector plungers that were accessible for adjustment to suit the preference of individual drivel’s (but I wonder if anyone availed themselves of this particular refinement!), a big alloy water jacket cover secured by 12 studs, full Enots grease-gun lubrication, while the brackets about the chassis, the hidden details of the brake gear and the throttle linkage, with proper pedestal brackets for the rack, etc., were the more or less equal. I suggest, of those found on the better large cars of the period. And there was the well-made Mulliner body…
None of these things prevailed against growing mediocrity and falling prices and the Calthorpe went out of production, along with a number of other small cars that were too well made to represent commercial propositions for their sponsors. I would be interested to learn whether mine is the only example of the Simplified 12/20 to survive (there are a few 10.4 Calthorpes in the V.S.C.C. membership list) and if the “water-dome” version ever got beyond the prototype stage? – W.B.