The occasion of this year’s British Grand Prix at Silverstone was also the twenty-first anniversary of the BRM team, for it was at Silverstone that the BRM V16 first appeared. Siffert made the Bourne firm a nice birthday present by getting his BRM on the front row of the starting grid, and it would have been rather nice if he had won the race. However, whereas the original BRM disgraced itself on the first outing, this year’s P160 car did not do that, and while running was running strongly and competitively. It was thought that the vibration which broke the coil mounting came from the rear tyres, this high frequency phenomena which appears from the inside wheel, which is lightly loaded, on a fast bend, also being the cause of the Lotus 72 breakages in practice. Ferrari are also worried by this problem and are still experimenting with dampers to suppress it, but even so Regazzoni was not at all happy while holding second place. The problem does not seem to affect the Tyrrell, but the reasons are obscure, and it seems to be generated by both Goodyear and Firestone wide-tread, low-profile tyres.
It was interesting that in the F3 race, with the “strangled” air-intakes on the 1,600 c.c. engines, Williamson made fastest lap at 109.99 m.p.h., and a lot of people recalled the first 100 m.p.h. lap at Silverstone as if it were yesterday, whereas in fact it happened something like twenty years ago. Of all the circuits on which Grand Prix races are held Silverstone has probably changed the least over that time, so that the lap record of 131.88 m.p.h. set up by Stewart gives a good measure of racing car progress. In practice he and Regazzoni recorded 1 min. 18.1 sec., a speed of 134.92 m.p.h., the fastest ever on the Silverstone circuit. It is also worth mentioning that lap times were recorded by Omega equipment presented to the RAC by the Shell Petroleum Company, a firm who have supported motor racing since the dark ages. This beam timing apparatus was recording to three places of decimals, and during practice numerous equal laps by different drivers were split to thousandths of a second, as shown in the Practice Times table.
While the Silverstone circuit shape has not been changed over the years the edges of the track are constantly changing, and in the early days there were some grumbles about the featureless inside edges of the corners, especially where they crossed the ends of the runways of this old war-time aerodrome. The line of the corners was marked by five-gallon oil drums, many of which were sent flying by the racing cars, so to make the perimeter-road track more like a road circuit, low brick walls were built on the inside edge of the corners. These made sighting easier and everyone was happy to have a clearly defined wall to clip with the front wheel in true road-racing manner. With the present changing faces of circuits these walls have been removed and replaced by plastic marker posts, to make Silverstone less like a road circuit and more like an airfield circuit.
Another change that has taken place, generated by all those who are concerned with safety, is the filling in of the ditches that were dug a few years ago to prevent a car skidding into the spectator enclosures. In their place the earth banks on the outside of the circuit have been reinforced with very solid looking railway sleepers standing on end and buried quite a way into the ground, and in other places there are very solid brick walls, so that anyone who goes off the track at high speed stands a good chance of getting badly hurt, though the spectators should be safe enough. As I suggested last month we should adopt the Oozlum Bird as the mascot of Grand Prix racing.
Now that almost everyone is using collector boxes for the engine air intakes there has been some muttering about their height being illegal, for on the face of it the rules say that no part of the coachwork can be higher than 80 centimetres above the lowest point of the car, and coachwork is defined as being “all parts of the car licked by the airstream and situated above a plane passing through the centre of the wheel hubs.” However, elsewhere the rules state that excepted from this definition are “the anti-roll bar (they mean anti-crash bar, or roll-over bar) and units definitely associated with the functioning of the engine or transmission,” and the collector boxes must surely be involved with the functioning of the engine, so all is well.
While on the subject of engines the scrutineers were going to measure Stewart’s engine when it was returned to the Cosworth factory, not because there had been any protests or suggestions that it was over-size, but because it has been a long while since a Cosworth V8 was checked for capacity, and what better one than the “absolutely standard” one in Tyrrell’s car. What the RAC engineers will not check will be the compression ratio, the valve timing, the cam profiles, the port shapes and valves, and all those little things that make one engine better than the next one, and there is no disputing the fact that Cosworth can produce a “better” engine if they really try. It’s just like the days of Coventry-Climax, all their 1 1/2 litre V8 engines were the same except the one that Clark used.
It would be difficult to award a bad luck prize at the Grand Prix, for Charlton deserved it for coming all the way from South Africa to have his engine blow-up on the starting grid, but equally Schennken deserved it for getting to a good third place only to have his car break four laps from the end. There were also people who said “What about poor old Graham Hill?”, but I’m afraid my reply to them was that if he had gone faster in practice he would have been further up the grid and out of the way of the charging Oliver.
With the glorious weather it was agreed that Silverstone was at its best and the way that motor racing should be, for nearly everyone who was anyone was there, and a very welcome guest was old Jack Brabham himself, looking splendidly fit and well, and it gave a lot of people great pleasure to see him again. Silverstone being an ex-RAF aerodrome, it came hack into its own, with one of the runways chock-a-block with private aircraft, and the queue to take off was nearly as bad as the queue to drive out of the gates. A very pleasant meeting all round, but not a memorable one.—D. S. J.