Boxer Vs 180° V-Engine | Flat Engines in Motorsports

In 1971, the 24 Hours of Le Mans took place from June 12th to the 13th. With the imminent ban of engines over 3 Liters for the upcoming 1972 season, the 1971 season would come to be considered as the year of the mighty engines. The 1971 season saw the introduction of the 2-by-2 rolling start behind a pace-car in contrast to the standing-start from the previous year. Additionally, drivers were now allowed to stay in their cars while refueling. The draw for car manufacturers to compete was the stature of the race as the first prize for outright victory was $13,000 US dollars - which was barely the cost of a top tier engine and not reflecting the huge preparation and work required.

The start of the race saw an onslaught of mechanical problems such as the Piper Ferrari and the North American Racing Team or NART Ferrari spyder which both had fuel system problems. The Piper car eventually joined the race again until its fuel pump gave out. The Martini International Porsche or car 21 driven by Vic Elford overheated it’s engine when a cooling fan blew off. However, the NART Ferrari faired worse when it ran out of fuel twice, flattened its battery and ran on low oil pressure.

As night fell and the race endured the Martini International Porsche car 23 had moved up to the third position when its cooling fan started to come loose. They had made it back to 3rd after the delay when the car’s driver, Reinhold Joest found he had no brakes approaching the Arnage section of the course. The Filipinetti Ferrari, car 7 had been in 5th position early on, but then got delayed fixing its fuel pump. Rushing to catch up, Mike Parkes, the Filipinetti’s driver crashed at the Maison Blanche section of the course at 1 am. Despite extensive damage, it was repaired but Henri Pescarolo, the Filipinetti’s second driver had to park it at 3am because of a lack of oil pressure.

When the sun rose and morning broke, the Matra race car went into the pits with a misfire at 6:20 am. The JW Porsche car 19 driven by Richard Attwood and Herbert Muller was able to get back into 2nd position after changing their spark plugs and fuel meter. With the delays facing other cars, the Piper Ferrari capitalized on the opportunity and steadily moved up the order. They had just got to third around 9am when their car lost another clutch.

At 9:40am, the Matra race car coasted to a stop at the end of the Mulsanne straight section of the course. Their faulty fuel-meter had failed, causing them to run out of fuel. Soon after the JW Porsche car 17 driven by Jo Siffert and Derek Bell retired from sixth after it had been delayed further with a crack in the engine’s crankcase. This had moved the NART Ferrari; car 12 driven by Sam Posey and Tony Adamowicz up to third and the Ligier prototype into fifth. Unfortunately, the Ligier's gearbox seized soon after.

By the end of the race, the order stayed pretty static through the afternoon and the race came to a subdued, incident-free end. Half of the twelve classified finishers were Porsche 911s and the overall win went to the Martini International Porsche 917K; car 22 driven by Gijs Van Lennep and Helmut Marko which completed 397 laps powered by a 4.9 Liter flat 12 engine.

The 1971 season marked an end of an era, with the regulations changing in 1972 limiting engine size in both Group 5 and 6 to 3 liters. It was the last time the Index of Performance prize was awarded and it was also the last run on a circuit layout that had been virtually unchanged for 39 years, with a new part of the track opened in the next year that bypassed the dangerous and fast, Maison Blanche stretch.

In this video, we will take a closer look at the history and mechanics that eventually drove the inspiration of Porche’s use of the flat engine in their cars.

The majority of sports cars throughout Porsche's history are powered by flat boxer engines beginning with its first car, the Porsche 356. The 356 used an air-cooled boxer-four engine during it’s 1948 to 1965 production run. The 356’s design overlapped the original Volkswagon Beetle in regards to an air-cooled four-cylinder, rear-mounted, rear-wheel-drive layout with unitized pan and body construction. Additionally, certain mechanical components including the engine case and some suspension components were based on and initially sourced from Volkswagen. The use of flat boxer engines in Porsches cars was essentially derived from the design ethos carried over from the original Volkswagen Beetle.