The progress in four-cylinder engine development is clearly shown by the new engine developed by Brian Hart for Martyn Griffiths to use in his defence of his RAC British HilIclimb Championship title. At 2½-litres, the new Hart’s performance can be related directly to that of the 2½-litre four-cylinder Coventry-Climax Formula One engine. That classic, twin-overhead-camshaft , two-valves per cylinder Grand Prix unit gave about 240 b.h.p. Hart’s DOHC, four-valves-per-cylinder hillclimb engine, designed for torque and a wide rev range rather than outright power, develops 335 + b.h.p. and 220 ft. lb. torque at 6,000 r.p.m.
“If it all holds together it should prove extremely exciting,” says Griffiths, who has put the engine into a new 1980 model Pilbeam MP40 G. He won last year’s title with a 2.2-litre Hart engine in an MP 40.
Mike Pilbeam’s new design features a revised nose, now more rounded with angular tabs to direct the air over the front wheels, in place of the former chisel nose flanked by side fins, and re-profiled side-pods with modified radiator ducting. The aerodynamic changes are designed to work without last year’s skirts, which are now banned.
Backing for Griffith’s latest challenger will once again come from Severn Advertising. — C.R.