Leyland Eight

Leyland Eight
1921 Leyland Eight four-seater tourer
Overview
Manufacturer	Leyland Motors
Production	1920–1923 18 made
Designer	J.G. Parry-Thomas
Body and chassis
Class	Grand tourer
Powertrain
Engine	6.9–litre OHC Straight-8 7.3–litre OHC Straight-8
Transmission	4–speed
Dimensions
Wheelbase	141 in (3,600 mm) 150 in (3,800 mm) 126 in (3,200 mm) (speed model)

The Leyland Eight was a luxury car produced by Leyland Motors from 1920 to 1923.

The car was designed by the chief engineer of Leyland Motors, J.G. Parry-Thomas and his assistant Reid Railton, and was intended to be the finest car available. It was the first British car with a straight-eight engine. The Eight was introduced to the public at the 1920 International Motor Exhibition at Olympia, London, where it was referred to as the "Lion of Olympia".

The engine, with cylinder block and upper crankcase cast in one piece, had a single centrally mounted overhead camshaft,hemispherical combustion chambers, and an 89 mm (3.5 in) bore. The engine was offered in one of two capacities: 6,920 cc (422 cu in) with a 140 mm (5.5 in) stroke, producing 115 bhp (86 kW) at 2,500 rpm or 7,266 cc (443.4 cu in) with a 146 mm (5.7 in) stroke and twin carburettors, producing 146 bhp (109 kW) at 3,500 rpm. The crankshaft ran in five bearings. Ignition was by coil and distributor rather than magneto which was the more usual British practice at the time.

Transmission was through a single plate clutch to a separately mounted four speed gearbox. The rear axle was unconventional with the differential mounted ahead of the axle. The spiral bevel crown wheel and pinion arrangement had two crown wheels each attached to a half shaft allowing them to be arranged at an angle to each other to give the rear wheels a positive camber.

The channel section chassis had suspension by leaf springs at the front and a mix of leaf springs and torsion bars at the rear. At the front semi-elliptical springs were used with radius arms controlling fore and aft movement of the axle. The radius arms were joined by a torsion bar across the front of the chassis to act as an anti-roll bar. At the rear the quarter-elliptical springs had their front ends mounted in a boss that was attached to a short transverse torsion bar which controlled the rotation of the boss making the suspension a hybrid arrangement. As at the front linked radius rods provided axle location and anti-roll properties.