A12 (1200): Further Refinements
The A12 is a 1.2-liter (1,171 cc) engine with 73 mm bore, like the previous A10 engine, but the stroke is increased to 70 mm. With five main bearings on a forged steel crankshaft, the engine is extremely smooth and durable. The 2-barrel Hitachi carburettor was significantly improved with the addition of a power valve circuit. It produced 70 hp (51.45 kW) and 70 lb·ft. (94.9 Nm).
A special version of the A12 called the "A12 GX" engine, was available (A12GX or A12T for front-wheel drive applications). With twin Hitachi sidedraft carburetors, a longer duration camshaft and 10:1 compression ratio, the engine accomplished 83 hp (62 kW) @6400 rpm, up 20% from standard A12 engines. The GX engine was offered in Japanese Domestic Market Nissan Sunny 1200 GX sedans and coupes. The identical specification A12T engine was offered in the front-wheel-drive Nissan Cherry X-1.
An overboard version of the A12 was used in period race cars, including Nissan factory (works) racing Sunnys. Many were bored from the original 73 mm to 76.76 mm using Tomei forged pistons for a displacement of 1296 cc while others used the Datsun Competition forged pistons of 76 mm to displace 1270cc. These legendary engines competed in Japan's Touring Sedan (TS) class races against the 1200s archrival Toyota Starlet.
Perhaps the most interesting variety of A series engines was the AY12 engine. This was a special race-only Nissan factory (works) racing version with a Crossflow cylinder head. (photo)
The AY12 was used in an under 1,300 cc class with a 76 mm to 76.8 mm piston. The intake valve was 40–41 mm and exhaust valves were 33 mm or 34 mm. The pistons were also a special design and the valve rocker system was different to the standard A12 due to the crossflow layout.
- Applications
- 1971-1973 Nissan Sunny B110, and B120 (Nissan Sunny Truck)
- 1971-1973 Nissan Cherry E10 (Datsun 120A)
- 1970 Nissan 270X Concept
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