X-ray spec: Under the skin of the Lola T70

John Surtees is full of praise for the design skills of Lola’s Eric Broadley. He worked closely with him on this stunning sports car. By Keith Howard

Sportscar racing assumed a distinctly transatlantic flavour in the 1960s when hybrids of European chassis and American V8s began to appear on US race circuits in significant numbers. In 1963, the SCCA created the United States Road Racing Championship to encourage the trend.

Lola’s Eric Broadley was quick to realise the sales potential for a car designed to accept a variety of production-based US engines, and his early involvement with the Ford GT40 project, which had grown out of his Lola Mk6 GT, provided invaluable background. It was this experience that explains, at least in part, why Lola’s resulting T70 is remembered as one of the marque’s great cars, whereas the Lotus Types 30 and 40— designed for the same market — have gone down in history as duffers. But there was a second important factor: John Surtees, whose Team Surtees joined forces with Lola Cars to form Lola Racing Ltd as a works development and racing arm. Surtees honed the T70, and in his hands it quickly proved itself capable, with a Chevy V8 in the back, of circulating British circuits faster than contemporary F1 cars.

“There are different criteria for a sportscar and an F1 car,” explains Surtees, outlining his philosophy for tuning the T70’s dynamics. “With a long-distance car you can’t have something that rides on a knife-edge like a top F1 car. When you’re testing and developing you’re trying to get consistency: you don’t want a volatile, unpredictable character. By the time the T70s got a bit of running into them they became very driveable, very predictable cars which you could drive up to the limit and perhaps a little bit over. This gave the driver confidence.”

Despite a major shunt in a T70 the year before, Surtees would prove the quality of Broadley’s design and his refinement of it by winning the inaugural Can-Am championship in 1966. Numerous other top drivers also piloted them in this period (Andretti, Bonnier, Donohue and Hulme to name but a few) before, in Surtees’ opinion, Can-Am was spoilt by big-money involvement from the likes of General Motors and Porsche.

Broadley and his team, which by then included Tony Southgate, turned the trick a second time in 1967 with the introduction of the T70 Mk3 coupé, the version shown overleaf. Aside from being devastatingly beautiful, it was aerodynamically daring in rejecting the usual fastback plus ‘Ferrari ridge’ spoiler for a flat rear deck with a slot down the middle to provide rear visibility and a relatively undisturbed air supply for the engine’s jutting ram pipes. Southgate put in many hours at the Imperial College wind tunnel and even consulted City University aerodynamicist A J Scibor-Rylski to develop the design, the rightness of which was confirmed when Porsche adopted a similar high-back configuration to such devastating effect in the 917.

There is no doubt in Surtees’ mind where Broadley belongs in the pantheon of race car designers: “There were two people who were outstanding on the British racing scene — Colin Chapman and Eric Broadley. Both gathered good people around them. Colin lacked concern about the final quality of the product — the fact that it fell apart didn’t seem to matter to him provided it had gone quickly before it did. Eric, in a quieter, more methodical manner, was very much an equal. But he had only a short time in F1, and all attention is focused there.

“Eric created some very fine motor cars. The important thing about Lolas was that they were user-friendly, and I hope we contributed to making them so with the development work we did.”

X-ray spec: Lola T70

An unusual feature of the T70’s brakes was that the discs, front and rear, were mounted inboard of the uprights to liberate them from the wheel well. Surtees: “This wasn’t just for better cooling but to reduce the effect of temperature on tyre pressures. You don’t build a light car when you put a big lump like a Chevy in it, so there is a lot of heat generated. If you can keep it away from the tyres and wheels, all well and good. Derrick White at Cooper had done the same on his F1 car.” From the Mk2 onward, ventilated discs replaced the Mk1’s solid rotors. “There was no particular problem with the Mk1’s braking, but you continue to improve. Making the brakes more consistent allowed you to extend the car more and continue to extend it.”

“I didn’t like the Mk3. The front suspension was altered and I hadn’t done any development and testing on the changes. I didn’t like the effect on the character of the car: it lacked the positiveness of the original and didn’t suit my style of driving. I didn’t mind a car being a little loose at the back at times, but I couldn’t stand something which you couldn’t point where you wanted. Some people tried to compensate by adjusting the aerodynamics, but I just stopped using the Mk3. Luckily the previous year’s car was still in America so we dragged that out of retirement.”

The T70 has been described as a superb chassis lacking a competitive engine, but Surtees demurs: “I’m not a great believer in using production-based engines in racing, but from the point of view of a series like Can-Am and letting it link in with the American public perception of racing, I actually think the Chevy engines were great.”

Nonetheless, in an attempt to create an all-British package, Lola got into bed with Aston Martin in 1967. It was not a happy marriage. “The Aston V8 could have achieved so much but was a total disaster. We didn’t expect it to compete on out-and-out speed — we were hoping to a degree that weather would play a hand. If it rained a bit, as happened at the Nürburgring and the Le Mans practice, we were very competitive. Before Le Mans we did a long test at Goodwood, 10 or 12 hours, but in the race we lasted only a few laps because Aston Martin had changed the design of the head gaskets! As soon as we got the cars back from Le Mans, we took the Aston engines out and that was the end of that.”

A second engine fiasco occurred when Surtees turned to Weslake to design and manufacture high-performance heads. “When the new aluminium-block Chevrolets became available they agreed to supply us with some, so we went to Weslake to build a batch of engines with special heads. In theory the engine should have been a winner: it was compact, had a nice layout with Lucas injection tucked away, and we took a bit of weight out of it. But the manufacturing let it down. We found we had one valve at one angle, another valve at a different angle. I had to ditch it.”

A big accident during practice at Mosport brought Surtees’ 1965 season to a premature end, and very nearly accounted for JS himself. It was caused by poor stock control. “We’d been negotiating with Lola’s US distributor, John Mecom, who was looking to make a certain amount of the car in America. They had sent some parts over for inspection, some of which were suspension uprights. These had become mixed up and were fitted to the car without being checked. The core had moved when they’d been cast, leaving a very thin wall which had lasted previous races but shattered on that lap. I came past the pits and the right-front wheel came off. The car hit the guard rail, I came out and it dropped on me. Rather knocked me about — ruptured kidneys, a split pelvis, broken femur and a cracked lower spine.”

The T70’s competition career coincided with a period of dramatic advances in tyre design, which Surtees made certain to keep abreast of. “In my bike years I’d always been very involved with developing and testing tyres. On the car side I did some development with Dunlop, then I become associated with Firestone over the T70 programme. I did virtually all Firestone’s testing over here and they were very responsive to my input. The war between Goodyear and Firestone meant that there were continual advances that you had to keep pace with and take advantage of in the car’s development. There was a lot of work done on springs and dampers as a result—we worked very closely with Koni. That brought its problems, too, because as you improve tyres you put greater stress through everything, but the car retained its user-friendly character.”

“The Hewland LG500 transaxle was a big lump, but there weren’t many alternatives and it was generally trouble-free, aided by the fact that the power characteristic from a 6-litre Chevrolet meant you weren’t changing gears all the time — you made the engine torque work. This is one of the benefits you have setting up this sort of car: you have a fairly progressive power curve. The last thing you wanted to do was let those engines rev their heads off. They would rev, but it was wise to keep them within sensible limits, and it wasn’t necessary for a lap time. About the only time you might let the engine rev hard was between corners when a change-up and a change-down might put even more load on it.”