Grand Designs

The clever Autobianchi Primula.

With its obvious Pininfarina inspiration and cheerful Italian provenance, the Autobianchi Primula might be mistaken for a version of its home market rival, the Innocenti-built Austin 1100. The story is actually far more interesting. Fiat’s Dante Giacosa was anxious to move on from the company’s rear-engined small car formula. He had already specified front suspension for the 1953 Fiat 1100 that could, if necessary, accommodate driveshafts.

The Autobianchi sub-brand provided an opportunity to innovate without risking Fiat’s reputation. The Primula was its most significant contribution. It presented what would become the default mechanical layout for front-wheel drive hatchbacks.

BMC’S 1959 Mini and 1962 1100 had combined the two-box silhouette of the Austin A40 with transverse four-cylinder engines driving the front wheels, but the group obstinately resisted the incorporation of hatchbacks and its drivetrain compromise placed the gearbox in the engine’s sump. The Primula pioneered conventional gearbox fitment on the end of a transverse engine. More than half a century later, it’s a layout used by at least three quarters of the world’s car production.

Nearly a gong

In 1965, and despite the international low profile of the Autobianchi sub-brand, the Primula was only just pipped to the prestigious Car of the Year award by the BMC 1800. Front-wheel drive was the future and five years later it would be the Fiat 128 successor that took COTY honours.

Legacy

The Autobianchi’s practical and logical drivetrain layout became the standard approach across the automotive industry. The layout was adopted for the highly successful Simca 1100 launched three years later and itself a major influence on Volkswagen’s 1974 Golf.

Giacosa vs. Issigonis

Having patented a very similar ‘gears in sump’ arrangement to Issigonis’s in 1947, Giacosa had been frustrated by the reluctance of Fiat management to embrace a transverse powertrain and frontwheel drive. If the Mini was a wake-up call, the licence-built Innocenti BMC 1100 one year later was a deafening alarm bell.

Passive safety

The press was happy to promote the then-novel transverse layout as a passive safety feature, with engine intrusion likely to be significantly less of a hazard in a frontal impact.

Rear suspension

A cranked tubular dead rear axle is suspended on longitudinal semielliptic leaf springs with double-acting telescopic dampers. This basic solution allowed a very low floor, exploited by a full depth tailgate.

New layout

The Primula brought together a transverse fourcylinder four-stroke engine set-up, as seen in the 1959 Mini, and a transverse end-on gearbox with its own lubrication, as featured in the 1949 twin-cylinder twostroke Saab 92. A transverse four-cylinder engine mounted in-line with the gearbox across the front of a compact car had not been attempted before the Primula, though the NSU Prinz 1000 launched a year earlier with a similar layout in its tail.

Practicality

Following a policy that Fiat had started to roll out a few months before, the steering, suspension and transmission were lubricated for life. Automatic adjustment of the clutch, brakes and handbrake helped to further minimise routine maintenance. The now-universal rigid cover for the luggage compartment was a novel feature. The boot’s 230-litre capacity became 750 with the seat folded.

Transmission

The Fiat 1100Dderived four-speed manual gearbox acquired synchromesh on first. The column change, though still common in the Sixties, was about to become a thing of the past. The off-centre offset differential and final drive dictated unequal length driveshafts.

Clutch breakthrough

Accommodating the engine and gearbox unit transversely made the first 1961 prototype wider than required for the planned market position. Fiat engineer Ettore Cordiano came up with a solution in 1963. Inspired by motorcycle engineering, his ultra-compact clutch was released by a coaxial rod within the gearbox input shaft operated by a hydraulic slave cylinder on the end of the ‘box. The usual thrust bearing and release arm were not required, saving valuable centimetres.

Wheels & tyres

Radial 145 R13 tyres came on 4J x 13in steel wheels.

Modern brakes & steering

The Primula was the first Fiat Group product to feature rack-and-pinion steering. It also had disc brakes all-round, first offered by Fiat a year earlier on its large 1800B and the 2300 saloons.

Temperature control

Engine cooling includes a thermostatic electric fan, a recovery tank and a split radiator, the smaller section of which supplies cabin heat. The radiator is placed conventionally behind the grille, unlike Issigonis’s side-mounted arrangements.

FWD roll-out

Fiat was quick to commit to front-wheel drive. Within five years the Primula had spawned the Autobianchi A111 and A112, with main board endorsement messaged by the simultaneous launch of the Fiat 128. The 127 followed in 1971.

Engine

The slightly undersquare Fiat ‘103’ overhead-valve cast-iron engine was the only inherited element of the innovative new car, having powered the rear-wheel drive Fiat 1100D of 1962 and being a direct descendant of the 508C unit of 1937. It is a simple watercooled unit with three main bearings, inclined forward in the engine bay by 15°. The different carburettor, filtration and manifolds chosen to permit transverse mounting and fit the engine bay delivered an extra 4bhp over the Fiat version.

Front leaf

The Primula was the last mainstream car launched with all leafspring suspension. The transverse front spring sits across the top of engine and gearbox, with lower wishbones providing semi-independent wheel movement. Like the Fiat 500 and 600 and Simca’s 1000 spin-off, the leaf features two outboard rubber-bushed clamps that cleverly extend the effective spring length and reduce the spring rate. Dampers are telescopic and no anti-roll bar is needed because the spring provides similar interaction between the front wheels.