MGA TWIN CAM SEBRING

Model Position: Less than two years after the release of the MGA 1500, very well received, competition is strong on small sports, particularly among other British manufacturers (Triumph, Sunbeam ...). A more muscular version of the MGA is required. Two prototype engines "B" DOHC were tested, one on the record car Ex-181 in August 1957. The MGA Twin Cam was finally marketed with the engine 1.6L DOHC in July 1958 In an externally little different crate MGA 1500. The front cover will be slightly modified to contain the new engine, and this modification will be also kept on all subsequent MGA models. Besides the engine, improving the Twin Cam covers Dunlop disc brakes, similar to those fitted to Jaguar at the time, replacing the front and rear drum brakes in 1500. Several options allow to further strengthen the character Sportsman of the Twin Cam (axle ratio, oil cooler, etc.). Despite a design resolutely focused on the competition, and therefore delicate maintenance, MGA Twin Cam is usually delivered to a common use. The consequences are dramatic for the engine and for the reputation of the model that will be produced only for two years. What they did note was that the balance of the production engines was well below the levels of precision that engineering had recommended and that the engine had two natural vibration periods at about 3200 and 5600 rpm. With stock gearing the 3200 rpm period coincided with typical highway cruising speeds. So they ran engines right at the rpm where they vibrated and found that the float on the rear carb would hang on its spindle and not drop which caused the rear carb to go full lean and hole either #3 or #4. Virtually every twin cam I have ever heard of with a holed piston had it on either #3 or #4. So flex mounting the carbs along with better balance was the solution but it came too late to save twin cam production".

The stock of parts planned for the Twin Cam (disc brakes, etc.) will be re-used on MGA Deluxe model. Variations: Mainly distributed in convertible version, the MGA Twin Cam was also produced in a few hundred copies in coupe version. During the period of production, changes in legislation will impose changes of lights and indicators front and rear. These amendments, which will be incorporated into the model MGA 1600, will also be carried over the Twin Cam contemporary. The latest Twin Cam had a lower compression ratio and limited power to 100 bhp, which made them hardly competitive with the latest generation of MGA 1600 Mk II. Distinguishing marks: Externally, the perforated sheet metal rims but central fixation butterflies are typical of the Twin Cam. The "Twin Cam" badges are present on the trunk and front fenders. The dashboard receives special instrumentation and is covered with fabric, while the upper shelf is treated anti-reflective. Better suited to competition seats are optional. They are often, but not always installed. Competition: Since August 1958, an MGA Twin Cam driven GOTT J. and R. Brookes is committed to the Marathon route Liege-Rome-Liege, forming the BMC team with 4 Austin-Healey 2.5 L. MGA and 3 Healey finished the event (among 22 of the 108 starters!). The MGA is 9th overall, while Pat Healey MITCHELL MOSS and Nancy are 14th and 15th, but occupy the first two places of the Ladies Cup. A MGA Twin Cam Coupe, driven by the same team at Marathon, is engaged in Monte Carlo in 1959, but crashed in the last step. 2 Twin Cam who come to the rally and the Tulip committed to the Acropolis that year, and one that presents the 1959 Alpine Rally unfortunately experiencing the same purpose. In that rally, are the new Austin-Healey 3000 which will become the reference of the BMC team in the following years.