The development of the M.G. Midget

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The Life History of a Car which might quite deservedly be called “Everyman’s Sports Car”

In view of its long run of success, amounting to ten years as a “best seller” among British sports cars, it seems high time somebody wrote a history of the M.G. Midget. Never having owned any M.G. myself, I am uniquely qualified for the job, so have taken it on. You have been warned!

The M.G. Midget first appeared in 1929. Since 1924 Cecil Kimber, of Morris Garages, Oxford, had been assembling sporting versions of the Morris Oxford, this enterprise prospering so well that a separate M.G. Car Company was formed, with its works at Abingdon-on-Thames.

The year 1928 saw the introduction of the Morris “Minor,” as a rival to the Austin Seven. In comparison with the latter, which had a peculiarly simple and individual chassis layout, the Morris “Minor” represented orthodox design on a small scale. An orthodox Channel section chassis having a wheelbase of 6′ 6″ was mounted on four semi-elliptic springs. The engine was of 8-h.p. rating, the bore and stroke being 57 mm. and 83 mm. respectively, giving a swept volume of 847 c.c. An overhead camshaft was driven via a vertically mounted dynamo at the front of the engine and a two-bearing crankshaft was fitted. The gearbox was a three-speed unit.

Working from the basis of the Morris “Minor,” the first M.G. Midget, the 8/33-h.p. “M” type, was produced. Mechanically, I think I am correct in saying that very few alterations were made to the chassis, but a light 2-seater fabric body was fitted, of pleasing pointed tail form and with rigidly mounted closeup wings. Marketed at £175, the current prices of the Austin Seven or Morris “Minor” being £125, this first M.G. Midget was an immediate success and the model was continued for four years. The rear axle ratio of 4.89 and the 27″ x 4″ tyres gave 3,050 r.p.m. and 1,660 ft./min. piston speed at 50 m.p.h.

The first racing Midgets came in 1930, when several cars were run in the “Double 12” at Brooklands, winning the team prize. These cars were 847-c.c. sports models, based on the “M” type, the most prominent departures from standard being 6.5 to 1 compression ratio, larger carburetter, external exhaust system and special sump.

The year 1931 did not bring any new production model, but an improved sports racing machine, the “C” type, was introduced. This type was of 746 c.c., the bore remaining at 57 mm., but the stroke being reduced to 73 mm. The engine still had a two-bearing crankshaft, but it was of counterbalanced type and advantage was taken of the reduced stroke to accommodate big-end bearings of increased diameter. The valve timing was changed – exhaust 50° before b.d.c. to 20° after t.d.c., induction 15° before t.d.c. to 55° after b.d.c., a timing which was, I believe, later used on all the overhead camshaft engines. Other features were a down-draught carburetter and plain four-speed gearbox, while a compression ratio around 9 to 1 was commonly used with Benzole fuel. The chassis of this model was quite different from the “M” type, being more akin to that used in a single-seater car prepared in 1930: the wheelbase was 6′ 9″ and the track 3′ 6″, while centre-lock wheels were fitted for the first time.

The year 1932 brought a new production model, the little-known “D” type, to supplement the “M” type. This car had a 7′ 2″ wheelbase and 5.375 axle ratio (3,350 r.p.m. at 50 m.p.h.), the price being £210, compared with £185 for the “M” type and £490 for the “C” type. In this same year the “C” type was fitted with a new cylinder head, to improve cooling and porting, 14-mm. plugs being adopted, also inlet and exhaust ports on opposite sides of the engine.

The year 1933 saw the introduction of the “J” type production cars, a big advance over the “M” type. Basically, the same engine was continued, with its two-bearing crankshaft, but the new cylinder head, with ports on opposite sides of the head, and a four-speed gearbox were used. The “J3” and “J4” models had the 746-c.c., 73-mm. stroke engine and a vane type blower between the dumb-irons and, though they carried sports equipment, they were primarily intended for racing. The “J1” and “J2″ were of 850 c.c., of course. An underslung 7′ 2” wheelbase chassis was used, with a 2-seater body of the same form as on all Midget 2-seaters up to the outbreak of war; fixed cycle-type wings later gave place to long wings-cum-running boards, but the slab petrol tank at the rear remained. This, strictly, refers to the “J2,” “J3” and “J4” models, the “J1” having a 4-seater body. Both “J1” and “J2” had 5.375 axle and 4.00/19 tyres, giving 3,350 r.p.m. and 1,830 ft./min. piston speed at 50 m.p.h.

The year 1934 brought two new Midget models, the racing “Q” type and the sports “P” type, fairly similar in general layout. In each ease. a three-bearing crankshaft was used, but, as previously, the 750-c.c. racing model had a 73-mm. stroke and the 850-c.c. sports car 83-mm. stroke. The “P” type used two semi-downdraught S.U. carburetters, as on the “J2,” but the “Q” had special valves and springs and was blown at up to 28 lb./sq. in. by a Zoller blower. This unit was driven positively at .69 of engine speed and was mounted between the front dumb-irons.

In chassis design there was a family likeness between the “P” and “Q” types, but the racing model was distinctly larger: wheelbase and track were 7′ 10″ and 3′ 9″, compared with 7″ 2″ and 3′ 6″ fr for the sports model. The “Q” type had a Wilson gearbox, the “P” type a plain four-speed: axle ratios were 5.375 for the “P” type and usually 4.5 for the “Q” type. Prices were £220 for the “P” type and £550 for the stripped “Q” type.

There was no change in the sports Midget in 1935, the “P” models continuing, but during the year the racing 2-seater “Q” type was superseded by the single-seater “R” type. This had an engine similar to the “Q” type in essentials, but the chassis was of backbone type and all wheels were independently sprung by torsion bars. Later, McEvoy and Pomeroy carried out experiments in high-pressure supercharge and developed a twin o.h.c. head for this engine. [Motor Sport, January, 1941.]

For 1936 a new Midget appeared, the “PB” type, supplementing the “P” type; the two models were very similar, but the “PB” type was bored out to 60 mm., giving a swept volume of 939 c.c. The main difference in chassis design was the use of slightly higher first and second gear ratios on the “PB” model.

Later on in the 1936 season another new M.G. Midget was introduced, the “T” type, replacing the “P” and “PB” models. As with the first M.G.s, the engine was adapted from another Morris-built car, the unit used in this case being the Wolseley “10/40.” A four-cylinder engine of 63.5-mm. bore and 102-mm. stroke, it had a three-bearing crankshaft and push-rod valve operation, carburation being still by two semi-downdraught S.U.s. The gearbox used with this engine was a four-speed synchromesh unit. Chassis dimensions generally were increased, though the same general layout as before was retained, the wheelbase becoming 7′ 10″ and the track 3′ 9″. Weight was about 16 cwt., compared with 15 cwt. for the “P” type and 14 cwt. for the “J2” type. A 4.875 axle ratio and 4.50/19 tyres gave 2,930 r.p.m. and 1,970 ft./min. piston speed at 50 m.p.h.

The “T” type M.G. Midget continued almost until war put an end to active sports car development, but 1939 did see a few examples of its successor, the “TB” type, put on the road. Chassis and body remained much as before, save for the adoption of box section frame members in place of channel section, but the engine was modified considerably. The bore was increased to 66.5 mm. (11 h.p. R.A.C. rating), but the stroke was reduced to 90 mm., giving a capacity of 1,250 c.c. General layout remained much as before, but the shorter stroke and the adoption of a counterbalanced crankshaft enabled the peak engine speed to be increased from 4,800 to 5,250 r.p.m. The axle ratio was lowered to 5.22, giving 3,130 r.p.m. and 1,860 ft./min. piston speed at 50 m.p.h.

That ends the record of M.G. Midget models marketed up to the present time. I have no inside information, but my own guess at post-war developments is a rehashed “‘TB” model and an 8-h.p. 918-c.c. Midget closely related to the 918-c.c. Wolseley Eight. Time will tell.

Hitherto a rather obvious omission on my part has been all mention of performance. This has been deliberate, for I have endeavoured to keep to facts and many performance figures quoted by owners for various M.G. models come more in the category of fiction. Power figures have seldom been published by the M.G. Car Company, and there has also been reluctance in recent years to submit cars for road test by the Press. I have been able to collect power data from two sources, and although they do not check against one another I am appending them for general interest; in particular, I regard the second set as distinctly optimistic.

I realise that I am treading on dangerous ground, but perhaps I can attempt to point some of the reasons for the phenomenal sales success of the M.G. Midget. Primarily, of course, low cost has counted. The Midget has always cost more than a small touring car, but it has seldom been possible to buy another sports car for appreciably less, and mechanical similarity to a touring machine has generally helped to keep replacements cheap. Secondly, the manufacturers, by building special cars and assisting private owners, achieved considerable racing success at moderate cost: there was always a strong family resemblance between racing and sports models to be advertised, even if the number of components that were identical on both vehicles was sometimes smaller than was generally realised. Finally, as with so many successful touring cars, everything possible was done to please the less knowledgable purchaser; he was given what pleased him, even if this entailed such disadvantages as carting unnecessary weight around, such matters as low seating at the expense of driving vision, really “good” speedometers, decorative stoneguards and good exhaust note being typical of what I have in mind.

These comments are not meant to be unkind. If the M.G. Midget has in some respects been displeasing to a certain number of die-hards, it has at least enabled many people to own an essentially reasonable sports car at a cost lower than would have been the case had less effort been made to sell to the “Promenade Percy” type of customer. Perhaps the end justifies the means.