Timeless Styling, beautiful build quality, a comfortable interior, taut handling, flexible engine, sparkling performance and well-controlled ride made the BMW M1 one of the most usable and practical supercars you could buy - a role only repeated much later by the Honda NSX. This makes it all the more sad that most now rarely turn a wheel, being tucked away in static collections.
BMW Motorsport chief Jochen Neerpasch wanted to hit rivals Porsche where it hurt - a car that would beat the 911 in Group 4, Group5 and at Le Mans. He commissioned Lamborghini to build it, hoping to launch at the 1978 Geneva Show before racing at Le Mans.
Giorgetto Giugiaro of ItalDesign was told to style a car that shouted supercar and BMW at the same time: he succeeded. With build quality guaranteed, customer versions finished to a high level, including air conditioning. Infinitely more reliable than their Italian supercar rivals, there was no more stylish or comfortable way to travel at 160+ mph with 60mph in 5.5 seconds, impressive even today. Giugiaro's compact bodywork encompassed a multi-tubular spaceframe chassis, while a twin-cam, 24-valve 3,453cc version of BMW's classic straight-six engine driving via a five-speed ZF transaxle provided the power.
But Lamborghini was going broke, failed to meet targets and BMW had to pull the plug. Worse, FIA rules changed and the M1 was suddenly a homologation special without a race series.
Neerpasch negotiated with Max Moseley to run a one-make Procar series supporting F1 Grands Prix, with top F1 drivers at the wheel. Niki Lauda took the championship in 1979, while Nelson Piquet bagged the title in 1980.
456 examples were built, a minimum of 400 being required for homologation to the proposed 'Silhouette Formula'.
The series was canned after BMW's attention turned to Formula 1 engines with Brabbham, but terrific PR had resulted, even if the dream of beating the Porsche 911 had faded. But who would build the M1?
Marchesi of Modena made the spaceframe and suspension. ItalDesign in Turin clothed the chassis with ten glassfibre panels that were made by Transformazione Italiana Resina, bonding and riveting the panels to the chassis, painting them and fitting the glass.
The rolling shells went to Baur at Stuttgart to receive engines, transmissions and interiors, before BMW at Munich carried out fine-tuning and road testing. Not surprisingly, the finished product was very expensive - more than a Ferrari Boxer - though dealers were said to have discounted dramatically, especially to customers favoured by BMW.
VITAL STATISTICS
Engine Iron-block, alloy-head 3453cc M88/1, twin-overhead camshaft, 24-valve, six-cylinder with Kugelfischer-Bosch mechanical fuel injection and Marelli contactless electronic ignition
Power 277bhp@6500rpm
Torque 239lb ft@5000rpm
Top speed 162mph
0-60mph 5.5sec
Economy 15-22mpg
Gearbox ZF DS25 5-speed transaxle with dog-leg first, limited-slip differential
WHAT TO LOOK FOR
INFREQUENT USE
Infrequent use wreaks havoc with the race-oriented M1, the biggest issue being with the dry sump oil tank located to the right of the engine: long periods of standing allow condensation to form on its inner face (above the oil line), water and rust fall into the oil and when the engine is started, it is sucked into the bearings and seals with disastrous effect. If buying an M1 that has not been used for some time, and has not had the tank replaced, it would be foolhardy to start the engine without first replacing this tank. It is a complex structure with internal baffles, and the BMW price is extremely high.
SPACEFRAME ROT
The spaceframe can rot, and is difficult to inspect as it is mostly enveloped by the glassfibre panelwork: put it on a ramp and all that's visible is the full-width undertray - endoscopes and cameras are needed to inspect things properly.
Front bulkheads and the tubes along the sills are usually the first places to rust. Corrosion also hits around the engine bay, where the heat of the exhaust causes the powder coating to lift, leaving bare steel open to the elements. The steel door shells can also rot.
COOLANT AND BRAKE PIPES
The coolant and brake pipes run through the central steel tunnel inside the car, and these can corrode.
Again a camera/endoscope is needed to inspect these sections properly, and if attention is needed you must budget for engine and interior removal before any repair work begins.
ENGINE CONSIDERATIONS
Almost any engine is very expensive, not just because of the engine's high state of tune but also because of its inaccessibility.
The engine came from racing CSLs in the 1974 IMSA series, with a double-damped forged crank to rev past 7000rpm. It is mounted low but vertically between the seats and the rear transaxle. You have to strip the interior to get to the inspection hatch for the front of the engine, and for most jobs, even setting the valve clearances, you have to take the engine out.
Unlike other supercars, the M1's engine is robust and capable of high mileages if well maintained; it will need timing chains at c100,000 miles and if neglected will develop worn piston rings and gasket problems. Check the coolant for signs of cylinder head gasket leaks, which may also indicate a cracked cylinder head.
Oil leaks from the engine are common and if severe enough to warrant attention, once again the engine must be removed. Leaks may also come from the gearbox.
BODYWORK
The glassfibre panels around the engine bay are fragile and often get broken, and are extremely expensive to reinstate accurately. Though made to a very high standard when new, the glassfibre bodywork is thin, as is its gelcoat, making it costly to restore successfully; cracks and crazing tend to occur around sharp corners such as the front 'boot' lid and pop-up headlamps.
Beware of cars where past resprays have rubbed through the gelcoat - get it in the right light and you will be able to see the glassfibre mat under the paint. Original paintwork was not high quality and runs were not uncommon.
IGNITION MODULE
The Magnetti Marelli ignition module can be trouble on infrequently used cars, and those that have reached high mileages. Replacements are unobtainable; it's usually possible for the unit to be rebuilt, but the process is time-consuming and expensive.
CLUTCH ISSUES
The clutch generally has a short life, and is extremely expensive to replace; parts are generally very costly and specialists complain of long waits for items to arrive from Germany.
WHICH ONE?
1978: The M1 was unveiled at Paris in October, and on sale from february 1979. There were no changes during production of the 390 road M1s and interior trim was always black and grey (Recaro seats in leather with black/white dot cloth centres), os your choice is limited to road or racing, which exterior colour you prefer (or can find on the market - Verona Red and Black were the most popular), and European or Federalised (US) specification. All were left-hand drive, and all had German-language instrumentation (UPM instead of RPM) and controls.
Federal cars had their heater controls swapped for Engligh-language ones from the 320i. All had air conditioning, electric windows, heated rear window, foglights and a Becker Mexico radio-cassette. Low-milers can make £300,000.
A few personal-import M1s were turned to Federal spec by Automobile Compliance Inc of California in 1980. Energy-absorbing bumpers and side intrusion bars added 79kg; catalytic converters reduced power to 235bhp and torque to 243lb ft. Often modified, Federal cars are less sought after and sell for £100k-200k.
Racing M1s are more of a minefield because the high value of the 49 original Procar racers encourages owners of the 10 or so other racers to make theirs into Procar lookalikes. BMW built one Group 5 race prototype with a turbocharged 3.2-litre engine and c800bhp, but it was unable to race. March also built one, failing to qualify in Group 6 for Le Mans 1979, later modifying it for Group C. Schnitzer built a twin-turbo M1 with Kevlar body, but didn't race it; they also modified an M1 to run on natural gas, gave it better aerodynamics and took the gas-powered land speed record at 187.2mph. BMW did qualify one M1 for Le Mans 1979, painted by Andy Warhol - The M1 Art Car achieved sixth overall and second in class driven by Manfred Winkelhock, Herve Poulain and Marcel Mignol. The M1's other great race was the 1980 Nurburgring 1000km, when Hans Stuck and Nelson Piquet finished third.
Procar ran in 1979 and 1980, with five cars prepared by BMW for the top five F1 qualifiers (if their tyres allowed them to race on ProCar's Goodyear tyres) and 20 other run by independent teams. Niki Lauda won in 1979, Nelson Piquet in 1980. The Group 4 alloy-block race engines produced 470bhp at 9000rpm and 282lb ft at 7000rpm. Weighing 2215lb (1005kg), they could reach 62mph in 4.5sec and top 192mph. All had a big rear wing, add-on wide wheelarches and a deep front spoiler. Gearboxes came with oil cooler, a choice of ratios and uprated final drive, while extra-wide Campagnolo wheels in the same design as the road cars were fitted. Rose joints replaced rubber in the suspension, with special springs, dampers and anti-roll bars, quicker steering and no brake servo. Genuine Procars are worth around twice as much as the road cars.