Citroen SM: Essential Collector’s Guide To The 1970s GT

The Citroen SM stands as a testament to bold engineering and visionary design from the early 1970s. Produced between 1970 and 1975, this grand tourer combined Citroen’s advanced chassis technology with a Maserati-sourced V6 engine, creating a vehicle that prioritized effortless high-speed cruising over outright sportiness. Despite its commercial challenges, the SM remains a beloved classic among enthusiasts for its unique blend of comfort, style, and innovation.

Origins and Development Challenges

Development of the Citroen SM began in the late 1960s amid financial turbulence at Citroen. The company sought to create a flagship grand tourer to rival established luxury models from Mercedes and Jaguar. Designers Robert Opron and Jacques Charreton crafted a body that was lower and more angular than the contemporary DS, incorporating space-age aesthetics with a long hood and fastback profile.

The partnership with Maserati was pivotal. Citroen, holding a stake in the Italian firm, commissioned a new V6 engine derived from Maserati’s V8. This 2.7-liter unit, later expanded to 3.0 liters, delivered around 170-180 horsepower, emphasizing smooth power delivery for long-distance travel rather than peak performance. Production totaled just 12,920 units over five years, curtailed by the 1973 oil crisis and Citroen’s bankruptcy in 1974, after which Peugeot took over.

Key components influenced future models: the drivetrain powered the Maserati Merak, the transmission appeared in the Lotus Esprit, and suspension tech carried over to the CX. This legacy underscores the SM’s forward-thinking design despite its short lifespan.

Striking Exterior Design

The SM’s exterior is instantly recognizable, featuring six concealed headlights under a glass fairing—the inner pair swiveling with the front wheels for better corner illumination, a feature borrowed from the DS. Its aerodynamic shape boasted a drag coefficient around 0.336, making it one of the slipperiest cars of its era, aiding high-speed stability and fuel efficiency relative to rivals.

The swooping nose and tapered rear gave it a futuristic look, often described as eyecatching and controversial. While the front evoked prestige, the bulbous rear divided opinions. Built with inherent structural strength, the body used advanced construction techniques for solidity. Stainless steel sill trims added luxury, and long doors facilitated easy access to the spacious interior.

Interior Comfort and Luxury

Inside, the SM offered a cockpit-like environment with one-piece seats in leather or fabric, providing excellent support for extended journeys. The dashboard featured aircraft-inspired gauges, and the left-hand-drive layout (standard for most examples) positioned the driver behind a massive, floating bonnet. Visibility was enhanced by a panoramic windshield, though the long nose required adaptation.

Space was generous for four adults, with a relaxed atmosphere suited to grand touring. Modern owners praise the airy feel, especially in lighter-colored interiors, contributing to its serene ambiance. Controls, including the single-spoke steering wheel, emphasized ergonomics, though some quirks like the eccentric gearshift demanded familiarization.

Powertrain: Maserati V6 Heart

At the core was the Maserati V6, a 2.7-liter (later 3.0-liter) engine with overhead cams driven by timing chains. It produced a distinctive growl on acceleration, settling to a refined hum at cruising speeds. Paired with a five-speed manual or three-speed automatic Citroen transmission, it emphasized rev-happy performance over low-end torque, ideal for sweeping roads.

Fuel economy hovered around 16 mpg in spirited driving, reasonable for the era but punishing during the oil crisis. Reliability concerns, particularly timing chain wear, plagued early units, but modern fixes make high-mileage examples viable. The engine’s sporting character surprised many, given the car’s civilised demeanor.

Advanced Chassis and Suspension

Citroen’s hydropneumatic self-levelling suspension, firmer than the DS yet supremely plush, ironed out road imperfections while maintaining poise. An engine-driven hydraulic pump pressurized suspension spheres, raising the car to ride height on startup. This system delivered uncanny ride quality, floating over bumps and keeping the body level under load.

Diravi variable-assist power steering, with just two turns lock-to-lock, provided self-centering precision and near-zero caster for maximum tire contact. Four-wheel disc brakes offered strong stopping power. These features made the SM a high-speed cruiser par excellence, rivaling Jaguar’s XJ6 in comfort and superior to many GTs in plushness.

• Hydropneumatic suspension: Absorbs bumps, self-levels
• Diravi steering: Quick ratio, variable assistance
• Swiveling headlights: Improves corner visibility
• Disc brakes: Progressive, powerful stopping

Driving Dynamics: Cruiser Supreme

Behind the wheel, the SM excels as a relaxed mile-muncher. The massive bonnet glides over undulations, the engine pulls strongly above 3,000 rpm, and steering feels alive yet undemanding. It’s not a corner-carver—push too hard, and understeer emerges—but it shines on undulating A-roads, sweeping majestically while drawing admiring glances.

Owners describe it as addictive, with a unique personality that rewards patience. The suspension cossets passengers, brakes inspire confidence, and the V6’s intake/exhaust notes add theatre. Fuel thirst and hydraulic maintenance are trade-offs for an experience unmatched today.

Ownership Realities and Maintenance

Modern SM ownership is rewarding but requires commitment. Hydraulics demand regular fluid changes to prevent sphere failure; engines benefit from timing chain upgrades. Parts availability is good via specialists, and values have risen—concours examples fetch six figures. Reliability has improved, with many exceeding 200,000 miles.

Common issues include fuel injection woes (carbureted US models are simpler) and rust in sills/wheel arches. LHD dominance limits some markets, but the driving pleasure outweighs quirks for dedicated keepers.

Legacy and Modern Appeal

The SM’s influence endures: it won Motor Trend’s 1972 Car of the Year for its innovative spirit. Today, it’s a concours star and competition entrant, proving its capabilities. Compared to Mercedes SLC or Jaguar E-Type, it offered superior comfort at similar speeds. Its bankruptcy link is overstated—Citroen’s woes predated it—but the SM symbolizes uncompromised ambition.

Enthusiasts call it life’s great pleasure, a high-functioning fusion of DS tech and Maserati power. In a world of sanitized modern cars, the SM’s eccentricities captivate.

Frequently Asked Questions

What makes the Citroen SM unique?

Its hydropneumatic suspension, Diravi steering, Maserati V6, and swiveling headlights set it apart as a technological marvel.

Is the SM reliable today?

With proper maintenance, yes—many achieve high mileages. Focus on hydraulics and timing chains.

How does it compare to contemporaries?

Superior ride comfort to Mercedes SLC or Jaguar E-Type, though less sporty.

What’s the top speed?

Around 140-150 mph, aided by aerodynamics.

Production numbers?

12,920 units from 1970-1975.