The truth about the S20 engine
The Nissan ‘Skyline 2000GT-R’ (PGC10, known as the ‘Hakosuka’) is a car that created a legend, a myth. It was the first mass-produced car in the world to be equipped with the S20 engine, a four-valve DOHC engine, and achieved a remarkable 50 victories in domestic races between May 1969 and March 1972. How was the engine refined and perfected to win races?
The S20 engine was designed for mass production
If we talk about the S20 engine used by the Nissan Skyline 2000 GT-R, we must mention the GR8 unit, the in-line six-cylinder engine of the prototype racing car Nissan R380. This is because the S20 engine was designed as a production version of the GR8 engine.
According to one theory, when the Skyline 2000GT-R was first announced, the S20 engine, the unit in which it was mounted, was announced to be a detuned version of the GR8 engine. However, according to one of the designers, it was quite different in terms of parts and there were many newly designed parts, and there was also the opinion that it was a different product.
On the other hand, some many developers and mechanics say that the basic concept, thinking, and direction of the GR8 engine were inherited from the GR8 and that it was definitely a mass-production version of the racing engine. In any case, there is no doubt that both engines were models with excellent performance produced by Nissan.
The first six-cylinder SOHC engine for a Japanese passenger car
While the fact remains that the S20 engine was based on the GR8 engine, that GR8 engine was also based on an engine. This was the GR7 engine installed in the first generation “Skyline 2000GT-A/GT-B”. This engine was originally installed in the Prince “Gloria Super 6” and was the first six-cylinder SOHC engine for domestic passenger cars.
The engine mounted in the first generation “Skyline 2000GT-A/GT-B” was a tuned version of that GR7 engine. What had been a counter-flow SOHC engine for racing purposes was evolved into the GR7B engine, which was converted to a rocker-arm DOHC V-type valve arrangement cross-flow. Records show that various port configurations were also tested here to further optimize air flow.
The GR8 engine was created by improving the efficiency of this GR7 engine and evolved as a higher-performance engine. It was tuned for higher efficiency and performance by securing rigidity for higher revs, reviewing the counterweight and fuel supply system, changing the carburetor, and increasing the precision of each part. In the latter half of the Nissan R380’s life, the maximum output was raised to over 220 hp. This was 10 hp more than the rival Porsche Carrera at the time.
