English: Porsche 356 Carrera Cabriolet

A very rare car undoubtedly. From 1955 up to 1964 Porsche produced not more than 165 units of the 356 Carrera Cabriolet.

The 356 Carrera Cabriolet was a special niche car, racers used Coupes and Speedsters, and the strongest reason for this was that the Carrera Cabriolet was the most expensive 356 available at the period. All of them were delivered as GS models, some equipped with many GT accessories for better performance, as shown on some cars on this website, but none or very few of them were used on the racetracks. As always with Porsche - never say never - it is believed that one car was delivered as a GS/GT, but that is another story.

It is possible to say that from the 356 models the Carrera Cabriolet is one of the rarest models ever produced.

Carrera... it is nice to remember when the purists appeared on Porsche events by the beginning of the 70s wearing shirts with the "Real Carreras have 4 Cams" motto on them. The Fuhrmann engine caused a lot of passion at its period and still does. I will try to concentrate on the facts rather than on emotions.

The heart of this special car was a race engine after all, the 547/1 roller bearing Spyder powerplant slightly detuned to 100 real hp from its 1498cc. The Carrera cars appeared together with the beginning of the 356A era - there are some exceptions on PreA cars, four Coupes and fourteen Speedsters have been identified.

The 4 cam engine was designed from the start in a very different manner than the normal pushrod engine. While they both had the same opposed four cylinder layout, the normal engine relied on pushrods to open the valves, the 4 cam used bevel gears and shafts. The plugs were fired from twin ignition coils, and a distributor was placed on the end of each intake camshaft to distribute the ignition spark.

A dry sump lubrication system drew oil from a storage tank into the oil pump, returning it to the engine by means of steel braided lines. Lubrication was critical in the 4 cam, as a roller bearing crankshaft manufactured by Hirth was used.

The Hirth crank moved a high-domed piston inside aluminum cylinders with chrome plated walls. Air cooling was, of course, used to help dissipate heat created in the engine; a large, rounded fan tower that was characteristic of the 4 cam’s appearance housed a fan capable of moving over 1000litres of air per second at high rpm.

The cooling system worked quite well, considering the ignition timing was set at 24 degrees before top dead center. This timing advance was necessary to create more horsepower propelling the lightweight Porsches to performance on par with larger displacement sports cars of the day like Ferrari and Jaguars.

A grey Coupe named Ferdinand was the first Carrera, as one of the first Stuttgart built Porsches it was the Professor’s last company car, this car went from the original 1100cc pushrod engine to the first experimental Fuhrmann 4 cam engine with 100 hp. Somebody said: That engine has done pretty well in a Spyder, let’s see how it goes in a 356. Dr. Fuhrmann had hoped from the beginning that his four cam would find its way into a production 356 body.

Porsche customers were crying for more horsepower, so Porsche installed the 547 engine into a 1949 alloy coupe, that won the Liege-Rome-Liege marathon as Porsche special and won it outright. Ferry then approved a small series of 50 or 100 4 cam cars.

They were designated 1500GS and named Carrera in honor of the Mexican race where Porsche Spyders had done so well. The launch coincided with the A model launch by September 1955, even tough we cannot say there were no PreA 4 Cam cars produced by Porsche.

The sales key were the engine, which would be built to full Spyder standards. The first ones were built with 9:1 with a rev maximum of 7.000 rpms, enough for 125mph. Each engine was run at the bench for several hours at 4.000 rpms plus several minutes at full throttle.

A 356 Carrera Cabriolet, the most expensive of them cost close to US$5.000 then, about the same total capitalization Porsche did 6 years before when founded his company. The original 50 cars had already grow past 700 sales by the 60s. The real competition Carrera came when Porsche divided the 1500GS line in GT and DeLuxe.

The GT was now available as stripped Coupe or Speedster with bucket seats, slide-up plastic windows, lighter bumpers, Spyder front ventilated brake drums, aluminum lids and doors to deal with the extra 10hps like the RS. Factory friends could even get engines with polished parts, higher compression ratios, and special cams.

When the title become 1600GS there was no more roller bearing crank. Engines 692/1,2,3 and 3A just like 587 which was designed first but followed in production, had 4 cams heads but plain bearings all over, they worked as well and moved the Carrera closer to production Porsches requiring less care.

Klaus von Rucker, the design boss then, plainly hated roller bearing cranks and once they had race proven plain bearing cranks he hurried them into the Carrera as a 1600cc, saving the available 2 liter version a while longer. The engine did require more oil cooling now, particularly for racing, so they added 33 feet of tubing to the 692 powered cars, carrying 10.5 qt. Of oil to a pair of coolers under the headlights and back with a thermostat controlling the flow. To prove that plain bearings could take it factory men often went to 8.000rpm in the gears posting 0-60 times at 10.8seconds. The so-called Sebring exhaust returned 15 extra hp to the track machines.

The single-leaf, transverse, camber-compensating spring which were fitted to most Carreras together with the new radial tires reduced oversteer in fast bends so you could drift one with an educated right foot. A works car in the Nurburg 1000 km, in 1959, was the first Porsche to try disc brakes in public but von Rucker noted that pads were gone in only 27 laps or 400 miles and also weighted additional 9 lbs. per wheel than their own drums.

If it weren’t for competition the Carrera tale would have to end temporally by 1959 when the 356B was introduced without a 4 cam in the catalogue. Porsche soon built a series of some 40 lightweight B coupes for 1960, using 1600 GS GT engines.

The next step was the 2000 GS, that began as a 356B too, the fastest road 356 ever built although its quoted top speed remained the same 125 mph. Actual sales began in April 1962, they were announced at the Frankfurt show in September 1961, and is the car which introduced disc brakes to the general Porsche public.

These brakes were the most confusing feature of the Carrera 2 history. Originally announced as a B with drums it became a road test bed for their own annular discs but was handed around for first press tests in early 1962 with drums after all. It stopped well that way but the pedal was heavy, eventual customer cars had Porsche Dunlop ring discs.

It remained the only road Porsche to use them, and it appears that a certain number of later Carrera 2s in the C body used conventional discs although some may have been conversions, these race-proven discs had the caliper inside the disc for greater leverage, reducing servo need, and smaller brake cylinders. The Porsche design was lighter than other normal disc brakes, racers used an alloy rather than iron calipers and German testers promptly rated them the finest brakes ever.

While they did stop the car short, extreme heat flowed outward to the securing bolts around the periphery of the disc ring and this began cause fractures around the bolt holes, at the end the design proved too costly to perfect. Porsche also toyed with a limited slip differential but confined it to the track cars.

The 1966cc plain bearing four was number 587, first design before Fuhrmann left the factory in 1956 and the first Porsche to use any but the 66mm stroke, at 74mm stroke these engines lead the pistons to a high speed of 53.5ft/s, the torque remained 94 lbs-ft with a wider green tach zone from 2200 to 6200rpm - with the red line band ending at 7000 rpm instead of the 8000 rpm from the first engines - that made this engine more easily mastered at the street use.

The 587 engine was also a bit heavier and an inch wider making even more difficult the plug changes. There was a GT option for the 356C line, generally with alloy doors, plastic windows on straps, close ratio gears and limited slip but Porsche do not recall that any of them had Carrera engines. Outside evidence points to a small series with 160hp engines.