Thursday, 14 November 2013
The new engine had much the same lower half as before, with a redesigned block and overhead valves so large they needed rockers on offset pedestals. Their seats extended to the edge of the combustion spaces. Double valve springs and substantial four-bolt Duralumin connecting rods were necessary for an engine that revved freely to 3400rpm – almost unheard of. The result was greater refinement but not, at first, a great deal more speed although in racing trim and with a high axle ratio 30-98s were guaranteed for 100mph. Later cars had a balanced crank and good hydraulic brakes. Wensum pictured at Windsor last year had a slightly taller windscreen than early ones and a whimsical Vauxhall bonnet mascot. Instruments were laid out flat and the colour scheme original-looking with black flowing wings which, according to a sales catalogue (when a Wensum was £1300 “complete”) reproduced in Nick Portway’s splendid Vauxhall The Finest of Sporting Cars 30-98, “offer little resistance to the wind and are fully effective in keeping the body clean.” Portway’s books are exemplars; essential for any student of the Vintage era. See www.newwensum.co.uk/ .
BODY: Velox fast tourer 1423kg (3136lb). Wensum sports 4 seater, complete car 1473kg (3248lb) chassis 1245kg (2744lb)
ENGINE 4 cylinders, in-line, front, 98mm x 140mm; 4224cc; compr: 5.2:1; 83.5kW (112bhp) @ 3400rpm; 19.8kW (26.5bhp)/l; rated horse power 23.8. Later cars 89.5kW (120bhp) @ 3500rpm
ENGINE STRUCTURE pushrod overhead valves; chain driven camshaft; detachable cast iron cylinder head; cast iron block; 5-bearing crankshaft; Zenith 48RA carburettor, pressurised fuel feed until 1923 then Autovac; Watford magneto ignition; water-cooled, honeycomb radiator, cast alloy fan.
TRANSMISSION rear wheel drive; Vauxhall multi-plate clutch; 4-speed gearbox; ENV spiral bevel final drive; ratio 3.3:1.
CHASSIS DETAILS pressed steel chassis, engine sub-frame channel pressed steel section; half-elliptic suspension all round; Hartford friction dampers; 4 wheel brakes from 1923, hydraulic in front from 1926; worm and wheel steering; 54.5l(12gal) fuel tank; 820x120 beaded edge tyres, centre-lock Rudge wheels to 1925 then 32x4.5SS rims.
PERFORMANCE maximum speed 144.5kph (90mph), 160kph (100mph) guaranteed when stripped for racing; 44.9kph (28mph) @ 1000rpm; acceleration 0-60mph, 17 secs; 19kg/kW (14kg/bhp); fuel consumption 15.7l/100km (18mpg).
PRICE chassis 1923 £1020, later £950