The new twin-cam M.G.
IT has been known for some time in motoring’s inner circle that the Nuffield Organisation has been working on a twin o.h.c. version of the existing M.G.A. to be supplementary to that popular sports car. Indeed, the new car was expected to appear at the Louden Motor Show last October but snags arose; delaying its announcement until the middle of last month.
The new car is virtually the same as the push-rod m.h.v. model-A, except for the new engine and disc brakes all round. The twin-cam engine has a capacity of 1.589 c.c. and gives 108 b.h.p. at 6,700 the output being 97 b.h.p. at 5,000 r.p.m. The engine capacity has been increased to take full advantage of the International Touring Car classification. As a speed of 120 m.p.h. is claimed for the twin-cam M.G. the makers have wisely specified disc brakes. These are Dunlop, in conjunction with centre-lock ventilated disc wheels. The body lines are unaltered, but the words “twin-cam” on boot lid and scuttle air exits give the game away to those surprised by the new M.G.’s performance.
Various extras are available for the new car, but its basic price, £1,265 17s. inclusive of p.t. (a coupé costs £1,357 7s.), is extremely competitive for a 120 m.p.h. car.
The engine is basically the 4-cylinder B-series B.M.C. unit with enlarged bore and a light alloy head with valves inclined at 80º and actuated by twin o.h. camshafts. The camshafts are driven by Duplex roller chain from a half-speed shaft located where the camshaft is on the normal engine, this shaft being driven by a gear-train from the crankshaft. The crankshaft has been stiffened and different con, rods and pistons are used. The compression-ratio is 9.9 to 1. A finned cast-alloy sump is employed. Polished alloy cambox covers make a handsome engine, to accommodate which the coolant header tank is situated beside the near-side cambox. Incidentally, the makers state that the M.G.-A cannot be converted to twin-cam specification, nor will disc brakes be available for this model.
The new engine has been in process of development for a considerable time. Prototype M.G.-As appeared at Le Mans in 1955, two of them finishing, in 12th and 17th places. For the T.T. that year one of the M.G.s had a twin-cam engine and two had Girling disc brakes. The twin-cam car was said to give nearly 110 b.h.p.; it retired. In 1956 the M.G. EX179 used a twin-cam when it successfully broke International Class F records at Utah and last year EX.181, which Phil Hill and Stirling Moss drove so fast at Utah, had a supercharged 290 b.h.p. twin-cam engine. So it was inevitable that this classic valve gear would sooner or later figure on production M.G.
The longer you wait the greater the anticipation, so it was with interest that we drove to Chertsey on July 14th to try the new twin-cam M.G. over a couse at the F.V.R.D.E., which the Nuffield Organisation had borrowed for the day.
Four open twin-cam M.G.s were available, although one retired early with a broken dynamo bracket and later another was crashed.
The makers claim that the best change-up speed is r.p.m. and that the car goes on accelerating beyond 100 m.p.h., this speed being reached from rest in 31 sec. and 110 m.p.h. in 38 sec. Maximum speed is claimed to be approx. 120 m.p.h. (But see below!).
The F.V.R.D.E. banked track was an unfortunate place at which to stage a demonstration of such a car, because even the better drivers could scarcely reach 100 m.ph. at the end of the short straight. The new engine seemed reluctant to go beyond 6,000 r.p.m. and after six miles “ran-on” furiously when switched off. The handling was excellent round the rough bankings and through the reverse curve but the steering was heavy and less pleasant than that of the M.G.-A. It was necessary to drive most of the lap in third gear to obtain a reasonable speed and the revs, appeared to rise reluctantly, compared with the push-rod engine. One journalist was clocked to lap in 1 min. 28 sec. and anything under 1 min. 31 sec, was good going on this approx. 2-mile track. Lowering the front tyre pressures made the car much more stable. The car gives plenty of power, without being noisy. A careful check of the oil-level every three laps was kept by the M.G. mechanics and the engines were seen to be running on a rich mixture.
Not a great deal can be determined during such track test. We had hoped to publish a hill road-test report on the new M.G. in this issue of MOTOR SPORT, however, at Chertsey we were informed that no car was available for this purpose as the hoped-for performance is not being realised. Consequently, we must reserve judgment on what could be a quite outstanding, sports car, particularly bearing in mind its price. Taking the average of two independent teat reportswhich hare been published. the t will.C31111 Nl I:. at present does 11 0101 reaches In° m.p.h. in 40.7 Sc,’,. ‘sill) a fuel consumption of 22 m.p.g —W. B.
(N.B.—The performance figures for the current twin-cam M.G. is of academic interest only in this country, because the first seven months’ scheduled production is accounted for by orders from America and Canada, which are worth over a million dollars.)
Exciting July B.A.R.C. members meeting at Goodwood
M. Taylor (Lotus) now leads K. A. Greene (Lotus) by One Point in MOTOR SPORT Brooklands Memorial Trophy Contest. Final on August 23rd.
There was particular interest in the racing at Goodwood on July 12th, because K. A. Greene led Taylor by a single point in the MOTOR SPORT Brooklands Memorial Trophy Contest. These two Lotus-Climax drivers came together again in the first 10-lap scratch race. Taylor had installed Stoop’s 1.220-c.c. Climax engine for the occasion. This gave him better initial acceleration and he beat Greene into Madgwick. After this it was Taylor’s race, although from a lead of 10 lengths on lap 3 Greene closed the gap to about three lengths by braking late for Woodcote, and on lap 9 closed right up. However, driving calmly and cleanly. Taylor held his lead, drawing away, to win by 0.2 sec. Arundell’s 1,093-c.c. Lotus Climax caught Westcott’s Lotus after three laps, to finish 3rd and Graham and Lumsden had a brisk dual for 7th and 8th places. Leston having come up into 6th place in Fisher’s Lotus. behind Martyn’s Lotus. No fewer than five Lotus cars were entered by lnnes Ireland. Taylor and Greene were now level on points;
A slow yet exciting Handicap for small closed cars saw Clarke’s Renault Dauphine, cool air led by a pipe to its carburetter, lead for four of the five laps, after which Lawrence’s Austin A35, after a splendid run into Woodcote, led a fine traffic jam through the Chicane. Gaston’s A35 coming through to finish 2nd. Sparrowe’s D.K.W. 3rd. A. B. Davies’ Standard Eight retired, but the VWs did not disgrace themselves. Griffin’s finishing 6th on the tail of the Renault, which had 20 sec. start, although a Fiat-Abarth did even better, to take 4th place.
Shale’s Austin-Healey 100-Six ran right away with the 10-lap Marque Scratch Race, front the Triumph TR2s of North and Ewer. Harrell spoilt his chances—he was leading on points in the Freddy Dixon Trophy—by going through the chicane wattle on to the grass and, although he swiftly resumed the race in an only mildly bent TR3, at Goodwood Members’ Meetings such exuberance entails disqualification. Fletcher’s A.C. Ace caught fire and burned for smite time, the scrutineers having insisted that the boot lid be wired securely, which made it difficult to get at the fire. Sleep’s A.G. Ace was 4th, followed by two T`R2s, the M.G.-As being outclassed.
Sheppard’s Jaguar XE120 won the big closed cars Handicap, from Cuff-Miller’s Ford Zephyr and Norris’ 3.4 Jaguar. Cuff-Miller delighting his public by repassing an XK120 into Woodcote. Hunt’s XK120 finished 1st but was excluded for leaving the course on the first lap. The spectators now prepared for an epic battle in the 5-lap Scratch Race between Taylor and Greene. Again Taylor got into Madgwick first—just—and led comfortably, to gain one point over Greene in the Brooklands Memorial Contest. Arundell spun, damaging his Lotus, as he has done before, Westcott retired, but 3rd place was contested by a close bunch—Martyn, Shale, Leston and Lumsden, all in Lotus cars, coining in in that order.
The rest of the racing, watched by a fair crowd, including a very keen clergy twin and his wife, was devoted to 5-laps Handicaps—and very oddly handicapped, too. Fredman’s Lotus won the first from Munns’ A.C. Ace and Trafford’s M.G.-A. Delapena’s pre-war Delahaye with faired helmet wings mid head rest 4th, Sanderson’s A.F.M. broke a half-shaft. In the next race the ancient Delahaye was asked to give Gillett’s Aston Martin DB2/4 a start of 20 sec. (!). Shale won in Trimble’s Lotus, from the Aston and Derisley’s Lotus-Ford. The last race was won by Steele, who made good use of Miss Seers’ Cooper-Zephyr, winning from Kines’ M.G.-A coupé and Twisk’s TR3. Gay’s TR2 retired with bearing failure.
The battle between Taylor and Greene at the next, concluding meeting should be worth seeing. Make a note-of the date—August 23rd. —W. B.