RUMBLINGS, March 1951
Rather belatedly we have received from the M.G. Car Company a copy of the book they issue detailing how to tune the M.G. Midget engine for competition work. M.G. Enterprise In the States ” hot,rodding ‘ is both an intense sport and a lucrative commercial venture, but in England hit-and-miss methods of increasing the power output of production engines have had to be employed, by amateur racing men, often with unimpressive, even unfortunate, results, because manufacturers refused to carry out any research as to what their power units would stand in this direction. Indeed, in many cases they all but forbade owners to Modify their own engines
At Abingdon it is different,and we are too that the greet M.G. competition tradition fostered by the late Cecil Kiniber, who founded the M.G. Company, is being carried on since his death. The lictok we refer to is a modest little publication in size, but an enormous amount of careful research and exhaustive beachtesting niust have been undertaken before it could be issued. Briefly, it gives details of the standard Type XPAC Midget engine and explains step by step how various increases in performanee may be obtained. Five stages of ” tune ” are recognised, but there are also variants of these, while for stages 2 and 4 power-Output figures are quoted for both petrolfbenzole and methanol fads.: From which it will be appreciated that almost every degree of specialisation is dealt with, to suit a wide variety of contests and pockets! It would, perhaps, hardly, be fair to divulge details of the tuning met taxis evolved by M.G., althoughwe understand that these me freely imparted to owners of their ears. But the subject M of enough interest, and reflects sufficient credit on this partioular Nuffield Organisation, to warrant publication of the accompanying power-curves. Curve S on our graph is for the standard M.G. Midget engine on 74-82 octane fuel, in which farm the safe maximum is 5,700 r.p.rns. and the ban.e.p. is 125 at 2,600 r.p.m. with a compression-ratio of 7.25 to I. The other curves are numbered to show the outputs available for each of the live basic stages of tune. Without. giving away the entire “bag of tricks” these stages can be saMinarised as under :-
s.rAutt I : Compre:,.8ion-ratio Increased ta 8.0 to I.
Si-tee: 2 : Compremkm-ratio increased to 0.3 to 1. larger Inlet and exhaust ,ttivv6. Strinoter valve springs. ftrAoR 3 Comorion-ratio ito.mowd to 12 to 1. Normal :ii7R
STAGR 4 Shorrook supervharger titled, giving tlibisu. in. boost at 5,000 r.p.m.
STAG!: S: Shorroek supercharger fitted, coMpre.c.sioreratio ineremml to 0.3 to I, larger inlet and exhaust valves and stxonger valve spring.
Ntrethettrole I used, except for Stages 3 and 5, t‘hich reqltire methanol mixture, and for Stage 4, wimell IsSaitablo for 70-metal’ (” Pool “) petrol.
The highest output quoted in the M.G. book is 97.4 b.h.p. at 6,0(X) r.p.m., when the Shorrock supercharger is employed in conjunction with a large carburetter, 9.3 to 1 compresidon-ratio, the larger valves and stronger valve springs, using .80 per cent. methanol in the fuel. This figure of 78 b.h.p.-per-litre from a L250-c.c., push-rod o.h.v. engine designed for a comparatively inexpensive sports car developing normally a maximum of 54 b.h.p.at 5,000 r.p.m. in standard form, is truly creditable. Study of’ the subject increases our already warm admiration for the ” T1) ” M.G. (see Moron. SPORT, August, 1950), and makes M.G. successes in the hands of private owners all over the world easy to understand. Incidentally, special parts for accomplishing these stages of tune are listed, so that tuned M.G. ears are eligible for Production Car Races—witness the winning of the Team Prize in the Dundrad T.T. by Stage 2 “TDs.” We pirticularly appreciate the sound sante contained in the foreword to this M.G. “Special Tune” book, which includes the following passages : ” There is a more or leas continuous demand from enthusiasts all over the world for information on methods of improving the performance for competitive purposes. It must clearly be understood, however, that whereas it is a simple matter to increase the power output, this cannot be achieved without the use of fuel haying better .anti-detonating qualities than ordinary “pump ” petrol. In addition, this increase in power must inevitably carry with it a tendency to
reduced reliability. This does not mean that tuning will necessarily make the car hopelessly unreliable. In fact, it may be assumed that. it will beat least as reliable as other ears of similar performance. The owner should select the simplest tuning method which will give him the performance he requires, remembering all the time that here, as elsewhere, power costs money.” • • As they gnaw at dry crusts until next week’s joint: comes, and stamp around their Portal homes trying to keep warm until the arrival of the next load of coal Down Under and stone, the minds of many Englishmen
must legitimately stray to Australia, where emigrants are apparently welcome. On the subject of ’emigration, we met a young enthusiast recently who was leaving for a new appointment in Cape Town ; the only unusual thing about this was that he told us he was driving there in a 1923 Cidcott, to which he had hastily fitted Morris-Cowley wheels in order to dispense with some rather faded beaded-edge tyres. The pioneering spirit still lives !
Reverting to Australia, it sounds rather like a land of milk and honey for British emigrants whose tastes lie in the motorracing direetion. Rally this year some interesting ears found their way there, including Chiron’s LagO-Talbot, the ex-Sommer 4C1. Maserati, a Cisitalia, two ” 2.3 ‘ Bugattis, two Type 51A Bugattis, and so on. These are likely to he -fielded against such potent vehicles as Cooper 1,000s and 1,1008, one with R.R.D. “Black Lightning” engine, already established there, and one Australian driver-is seeking a 4CTL/48 Maserati. It seems that racing ears can be freely imported from France and Italy. Moreover, prices are comparatively reasonable. For example, we hear that the Chiron Talbot’ in almost new trim., with spare parts and a selection of wheels and tyres., cost 22,500, the ex-sonuner Maserati less than £1,900, and a rating Cisitalia with loads of spares a mere MO.. Which makes some of the rattier breathless racing and sports eats for sale in England look a bit pricey. Arthur Wylie, Editor of Atocrizliyis MOW Sports, tells us that even those without much money can rake, by building ” speciala ” in Which considerably modified stock-car engines give a good account of themselves in extremely light-Weight chassis. He practises what he preaches, having on the stocks a racing .lowett Javelin with engine at the back, independent suspension all round, a tubular chassis and a starting-line weight. of under 8 ewt. The engine has ” solid ” tappets, a modified lubrication system, 6 to 1 compression-ratio and a Shorrock supercharger boost at 15-18 144sq. in. The car has been built in something like seven months’ spare-time hard labour. Incidentally, Wylie’s brother has been racing an interesting car that looks rather like one of the larger American midgets and, it seems, calls for quite 11 lot of driver-skill when in
action. This is hardly surprising, as it weighs not much more than 94 cwt. ” wet ” and achieves 118 m.p.h. The engine is an Austin A40 with 9 to 1 compression-ratio, supercharged to 10 lb./sq. in.; 60 per cent. methanol fuel is used. This car has recently found a new owner in Sydney.
Finally, before returning from Down Under, George Brooks tells us of a distillery adjacent to the Nuriootpa race-course, where wine sampling is combined with prize giving after the racing. We feel we have now ensured an adequate response to the appeal for emigrants to Australian soil.
The 19th Le Mans 24-Hour Race will be held on June 28rd/ 24th. Entry is by invitation. Two Aston-Martins, a D.B., Healey, Jupiter, Monopole, Allard and Aero-Minor are eligible for the Final of the 17th Biennial Cup, together with 21 drivers in any cars they care to nominate. The latter include Peter Clark, Norman Culpan, E. R. Hall, H. S. F. Hay, R. Lawrie, N. H. Mann, G. E. Phillips, Mrs. Trevelyan and Peter Walker.
The International Evian Mont-Blanc Rally will be held on July 27th/29th. Regulations will be ready next month, from the Automobile Club du Mont-Blanc, Rue Camillo-Dimand, Annecy. The excellent scheme of the Manx A.C. to run a Production Car Race over the I.O.M. Motor-cycle T.T. circuit has unfortunately had to be abandoned this year. The R.A.C. has expressed alarm about marshalling such a long circuit (but isn’t this done satisfactorily for motor-cycle T.T. races ?) and has recommended alterations to the proposed course, the total
cost involved being £5,350. In addition the I.O.M. Government Committee says inconvenience might be caused by further closing of the roads. We are glad to learn that the Manx A.C. remains firm in its resolve to overcome the suggested difficulties and stage the race on a future occasion. 44444* ****** •••••••••• ***** • *****•••••••••••444.444444w*****