VIDEO: Gordan Murray explains how Cosworth builds the V12 engines for the GMA T.50

“It feels like I’ve come full circle. It started with my first GP win on a Cosworth DFV engine in 1974, and now I’m up against this beauty,” says Gordon Murray, looking at the Cosworth V12 engine soon to be found in his GMA T.50 . In the video at the bottom of this page, Murray discusses the precision work that Cosworth delivers for this twelve-cylinder.

According to Murray, Cosworth is the only company in the world eligible to build his 12,000rpm revving dream engine. They fell silent for a moment as Murray unfolded his plans for them, but Cosworth has exceeded his expectations. ‘When I look at the details on this one [motor]… I mean, I could watch this all day,” says Murray.

The crankshaft of the Cosworth V12

In the engine’s first stage, Murray highlights the crankshaft, which he says is a masterpiece. The part is constructed as narrow and as compact as possible. Cosworth boss Bruce Wood calls the crankshaft “the pinnacle of all that [Cosworth] did’. In total, the crankshaft weighs 13 kilos, which is incredibly light for a V12.

Murray is also surprised by the size of the connecting rod bolts and the fact that O-rings have been used. Those washers are there to make sure that no oil from the engine comes out through the threads and nuts. “Bruce told me the other day that he sees these cars in great garages with white floors,” Murray says of the reasoning for the O-rings.

Phase two

At the second stage, the cylinder heads were added. The cams have to do the same thing over the entire length of the cylinder bank while an awful lot of power is going through it. To ensure that the camshaft does not twist, it is made extra thick. That would logically cause more weight, but Murray is allergic to that, so something has been found for that too. The axle itself is hollow inside to save weight.

And there are plenty of tricks that Cosworth conjures up from the top hat. For example, there are hydraulic dampers on the ends of the camshafts to absorb vibrations and keep them working exactly as the builder intended. “Solutions to high-speed problems,” says Murray.

Cosworth also incorporates a racing trick into the valves. The intake and exhaust valves are slightly tilted to allow as much fuel and air as possible into the combustion chamber. Even more racing magic can be found at the distribution. This does not take place via a belt or chain, but via gears. That’s the only way to get to 12,000 rpm.

The Swiss watch

“It’s kind of a Swiss watch, isn’t it?” says Murray. The disadvantage of the gears is that they are quite fragile. Cosworth came up with something about that a while ago: the so-called Cush gear. This part uses a shaft between the front and rear sprockets to eliminate friction and vibration.

Then Murray points out the two gears that control the camshaft timing. There are two gears per bank that are hydraulically controlled. A large part of the high torque at low rpm is due to these components. Cosworth had to make the electric actuators that set the whole party in motion. Other companies could not supply parts that could handle 12,000 rpm.

The power of the Cosworth V12 for the GMA T.50

Then the final product: the twelve-cylinder as it is installed in Murray’s cars. Before that, the engines are allowed to whine on the dyno for a few hours to obtain a certificate of approval. The goal was to get 650 horsepower out of the engine. “We’re at about 670 now,” says Murray. The couple is also much better than Murray expected. At 2,500 rpm, about 70 percent of the torque is already available.

The founder of GMA compares his new engine to that of the McLaren F1. The BMW engine in that car has twelve throttle valves that do not open and close at the same time. To bring the timing closer together, Cosworth put a plenum chamber on the engine that distributes all the forces. With that, only four throttle valves are needed, which is easier to time.

Surprise for Murray

At the end of the video we see another nice encore for Murray. In a room further on, 23 Cosworth V12 engines are on pallets waiting to be placed in a GMA T.50. All added up, there is 15,000 horsepower in power. This space contains almost a quarter of all engines for the T.50s. Only 100 of them will be built. Watch the video below.