1972 Chevron B21

The Chevron B21 was a Group 6 racer built for the 1972 season. It built on the success of the prior Group 4, 5, and 6 cars that included the B16, B8, and B6. The chassis was based on a reinforced steel spaceframe with the earlier cars using steel and duraluminum. The B19 was clothed mostly with aluminum and many of the customer cars used the Cosworth FVC engine.

All of the B16 models were coupes except for a single spyder fashioned after the Porsche 908/3. The B19 that followed for the 1971 season was essentially the production version of the B16 Spyder.

The B21 that followed for the 1972 season was a further developed version of the B19. Most of the engines were the BMW M12 straight-4 with a 1998cc displacement, dual overhead camshafts, four valves per cylinder, and Kugelfischer Fuel Injection. The aluminum-reinforced steel spaceframe was clothed with a fiberglass body and ventilated disc brakes at all four corners. The front suspension consisted of double wishbones with coil springs over dampers, and anti-roll bars. In the back was a single top link with twin lower links, twin trailing arms, coil springs over dampers, and anti-roll bars. The Hewland 5-speed manual sent the power to the rear wheels.

The best result for the B21 during the 1972 season was by John Hine and John where they finished third overall and first in class at the Spa 1000 km. Dieter Quester scored a victory at the Salzburgring round of the European Championship, and Hines and Bridges captured another class victory during the Nürburgring 1000 km race.

The B21 with the tried-and-true spaceframe chassis had brought several important victories to Chevron, but as the season progressed, they were consistently falling behind the Lolas with the more modern monocoque chassis. A redesign was certainly in order.

In efforts to keep the B21s competitive, several examples were later upgraded to B23 specification and are commonly known as B21/23. The modifications included a revised front suspension to better accommodate the new racing slick tires. Gerry Birrell found success in the Springbok Cup racing a Cosworth BDA 2-liter engine. With four victories and a dominant performance, he was crowned the champion.

For the following season, the B23s were given the revised suspension and achieved class victories at the Nürburgring 1000 km, the Osterreichring 1000 km, and the Targa Florio.

Chevrons were both successful on the track and the salesroom. Thirty-five examples of the B19 were built, followed by 28 of the B21.

by Daniel Vaughan | Feb 2020