Back at North Weald to try and perfect the starting technique did not produce the results we had hoped for. It was impossible to ‘break the wheels loose’ no matter at what revs the clutch was engaged. After numerous attempts smoke started to pour out of the clutch housing and that was the end of the days testing. The size of tyres we were using 7.00” x 16 were not too large, however we either had insufficient power related to the rear axle weight, unsuitable overall gear ratio or the clutch was not of sufficient capacity. Once back at Clapham the clutch assembly and flywheel were inspected and as well as the pressure plate showing signs of excessive heat the Scheiffer aluminium flywheel had signs of surface cracks. The condition of the flywheel gave cause for concern and brought home the need to have a safety housing around the clutch area to protect not only the driver but also bystanders should the clutch disintegrate.
Rather than just simply getting another American flywheel and clutch assembly we spoke to Automotive Products, Borg and Beck 5 and were recommended to use the multi plate clutch which had been designed for the V16 BRM. This was a multi-plate sintered iron clutch, the disc’s being no more than nine inches in diameter. It’s designed capacity was well in excess of our potential maximum torque predictions, so rather than return to the American design there was now a need to fit it into what was a relatively large diameter bell housing but of limited depth. In addition a new flywheel was needed and much thought was given whether to use aluminium or steel. Aluminium could have been used coupled with a steel faceplate. The design of the flywheel constituted a number of problems which needed to be addressed properly, rather than just get a piece of steel and machine one up to suit. This was the approach of some of those involved in the car. A little knowledge is a dangerous thing and rather than take the easy route and end up with a disaster, a section was designed which would have an adequate safety factor, up to and exceeding 8000 rpm. In the end a billet of mild steel was found and X rayed to ensure that there were no hidden flaws.