4AB Roadster

Although virtually indistinguishable at a gallop, the 4AB began to show some external signs of differentiation from its predecessors. Notably, the radiator and shell were shortened, terminating at a neat valance at their base, whereas on previous models the shell had extended well below the bumper level of the car. Its wings were restyled to become more sweeping in appearance and the bonnet now had fixed sides with the top centrally hinged. The wheels received modest treatment with a change to the slotted disc type.

In the passenger compartment, Singer added a set of deeper, springed seat cushions and higher seat backs for added creature comfort.

The 1074 cc engine continued to power the 4AB and the chassis was essentially that of the 4A with additional stiffening at the front end. A massive box section cross member was added to carry what was really the most significant change to the Roadster series to date – the coil and wishbone independent front suspension units.

Steering was modified on the 4AB whereby a three piece track rod was adopted, with an idler shaft connecting to the steering box. This was done in order to create a symetrical layout conducive to fitting the car for either right or left hand drive. A forward mounted anti-roll bar was also added.

The other change of significance was the upgrade from an all mechanical to the hybrid Girling hydro-mechanical braking system.

Date of Manufacture— 4AB Oct. 1950 to Jan. 1953

Serial No. location — Brass plate under bonnet.

Engine
Firing order 1,3,4,2Four cylinder, 60 mm. by 95 mm. = 1,074 c.c.
                       :in 2.3622 X 3.7401 :cu in 65.54Single overhead camshaftRAC rated 9 hpCompression ratio 6.9:1 Maximum power 36 b.h.p. @ 5,000 r.p.m.Max Torque 47 lb/ft at 2800 r.p.m.Single Solex downdraft (30 F.A.I) carburatorIgnition Lucas coil

Gearbox and TransmissionBorg and Beck 7 1/4 in. single dry plate clutchFour speed gear box with ratios 5.43, 7.96, 12.32 and 19.5 to 1. Reverse 19.5:1Synchromesh on second, third and fourth gearsHardy-Spicer open propeller shaftSpiral bevel final drive

Wheels and Brakes16 inch pressed steel easy-clean wheels5.00 X 16 inch Goodyear tiresTyre pressure: 20 lbs. sq. in. front, 22 lbs. sq. in. rearGirling hydro-mechanical brakes with 9 in drums

SteeringBurman high efficiency

SuspensionFront independent coil, rear semi-elliptic leafFront Armstrong telescopic shock absorbersRear Armstrong direct acting hydraulic shock absorbers

Main DimensionsWheelbase 7 ft. 7 ins.Track 3ft 10 3/4 inOverall length up to chassis No. 4AB7750U-12ft 6in.
                       From Chassis No 4AB7751U-12ft 7 1/2inWidth 4 ft 10 inHeight (hood up) 4 ft 10 1/2 inTurning circle 33 ftGround clearance 6 1/2 inWeight 15 1/2 cwt

Price
£450 plus £125 15s purchase tax