Porsche’s Gamünd Roadster 356 debuted in 1948. It was a coupe with a top speed of 83 mph that enjoyed a spirited run of eight years, sporting several engines.
Porsche released its first production car in 1948 as the Gamünd Roadster 356. It was a coupe, with a top speed of 83 mph and weighed just 1,289 pounds. It enjoyed a spirited run of eight years, sporting several engines with varying displacements from 1.1 to 1.5-liter.
We review the rich automotive history of the short-lived engine and its impact on mankind’s never-ending quest for faster machines.
Porsche 356 Engine: Launch of a Legend
The 356 started life with a 1.1-liter air-cooled Volkswagen flat-four engine with a single carburetor. Porsche engineers raised the compression and beefed up the intake and exhaust valves to increase its horsepower from 25 to 40.
Porsche had equipped the 356 with a 1.3-liter flat-four overhead-valve engine in 1951. This engine used a two-piece crankcase with a forged steel crankshaft and lightweight alloy cylinders, saving 12 pounds from its 1.1-liter predecessor. The increased displacement and improved parts upped the horsepower to 44.
Porsche made incremental improvements to the 1.3-liter engine’s power. From 1954 until 1955, it had 59 horsepower, offering a top speed of 99 mph using overhead valves.
By 1951, the 1.3-liter cylinders were bored to the limit, so engineers increased displacement with a longer stroke by 200ccs. Porsche accomplished this using flat-topped pistons.
This iteration of the 1.5-liter made 60 horsepower with a lower compression ratio of 7.0:1 and a top speed of 92 mph.
The 1953 356 got two additional engine options. One option went into the 1500 Super and was a 1.5-liter with 8.2:1 compression which produced 70 horsepower, allowing the car to reach 100 mph.
The other engine option was for the 356 1500 Speedster, which saw the 1.5-liter engine with 55 horsepower, and a top speed of 96 mph. 1954’s 356 saw an improved 1.3-liter, amidst the 1.1-liter’s dwindling sales. Using a longer stroke and smaller cylinders, the compression raised to 8.2:1 and produced 60 horsepower.
Porsche 356 Engine Maintenance
The Porsche 356 engine is generally considered a reliable engine, due to its simplicity. Nevertheless, preserving its reliability requires attention and diligence.
Porsche mechanics recommend checking valve clearance about every 6,200 miles. Oil changes are less straightforward than they are in a modern car. The oil strainer and magnet within the oil pan should be cleaned prior to adding new oil. Mechanics also recommend checking the distributor as part of regular maintenance.
While the car already comes with what’s called a “coarse” fuel filter, it only protects the engine from large foreign particles. Smaller substances can break through into the carburetor.
An additional fuel filter for finer particles should be installed in the fuel line. Carburetors are intricate and therefore fickle. They have many tiny passages and parts that work in unison, so if one piece of dirt is caught within it may not function properly, and may require a teardown and rebuild.
On that note, the 356 carburetors are a matter of preference. The car comes with either Zenith or Solex branded carburetors. According to Porsche experts, the Solex carburetors are more difficult to tune, and often replaced by Weber carburetors.
However, different schools of thought consider the Solex to have smoother power delivery, while Weber carburetors deliver sharper throttle response.
Porsche 356 Engine Problems
Possibly the biggest issue facing the 356 engine is its cost, simply because the parts are so rare. With a proper rebuild it will last for a long time, but obtaining that peace of mind can cost more than $10,000. Some enthusiasts install a VW engine to avoid the costs, but these engines reportedly don’t last as long because of inferior materials.
Other issues that might crop up under 356 ownership are overheating and oil consumption. Seasoned drivers report the 356 engine as burning up to a quart of oil every 1,000 miles. A 356 expert from California Chris Casler recommends checking the oil regularly, and if the oil level is low enough, add half a quart until the amount is correct.
While air-cooled engines require fewer parts and are simpler than liquid-cooled systems, they are more prone to overheating. Overheating unfortunately requires discipline to avoid.
Spirited drives under high revving conditions, like mountain passes or autocross, serve as circumstances that prevent the engine from dissipating some of its heat.
As long as the revs are kept in check and the engine has a chance to stretch its legs, overheating will be a distant worry. Allowing overheating causes the engine block and cylinder head to warp and thus no longer seal properly, lowering the compression.
Additional woes of overheating include detonation, piston scuffing, and damaged valves.
Porsche 356 Engine Upgrades
Smaller displacement 356 engines are maxed out from the factory, but the larger displacement engines yield a bit more leeway. Willhoit Auto Restoration cites a common engine build involving an 86mm big bore kit, hotter cam, Solex 40P11 carburetor and a Bursch exhaust, an ensemble that produces 120 horsepower.
A “hotter cam” refers to a larger camshaft than what came with the engine from the factory, though according to some this means staying at higher revs.
Other enthusiasts suggest upping the displacement to 1720 ccs, along with chrome-moly pushrods and an aluminum oil cooler. Some owners prefer Weber carburetors for their ease of use. However, investing some time into understanding the intricacies of the Solex may provide a better experience.
A taller fourth gear is a way to combat overheating while driving on the highway. Casler reports that at 80 mph cruising speed a taller fourth gear lowers the engine speed by 750 rpm.
Engine Swapping A 356
A Chevrolet V8 fits inside a Porsche 356 with some encouragement. However, buying a rebuilt higher displacement 356 engine is the best way to keep the 356 pedigree while making it as fast as possible. These cars weigh little, so a lot of power isn’t necessary to drive them fast. The engine’s strong suit is its simplicity, and considering rebuild costs, its reliability is not a viable sacrifice.
Even modifying it to use liquid cooling would add weight and complexity, not just with parts but with chassis modification as well. It’s best to improve the existing air-cooled system as much as possible. The Porsche 356 is a proper driver’s car, just a bit dated. Preserving reliability is key, and improving the brakes is always a plus. Porsche went the extra mile to provide modern drum braking for Porsche 356 A owners as well.
However, drum brakes are more complex and harder to service and don’t provide stopping power as well as disc brakes. If keeping the car original is last on the list of concerns, consider a disc brake conversion if available.
Photos: Porsche
