Manufacturer Mitsubishi Motors Production 1969–1999 | Also called Saturn Cylinder block alloy Cast iron | |
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This article is about the engine series produced by Mitsubishi Motors. For the engine series produced by the Saturn subsidiary of General Motors, please see Saturn I4 engine.
Contents
The Mitsubishi Saturn or 4G3 engine is series of overhead camshaft (OHC) straight-4 internal combustion engines introduced by Mitsubishi Motors in 1969, along with the Astron, Orion, and Sirius. Displacement ranges from 1.2 L to 1.8 L. The early versions have chain driven valvetrain while the later versions are belt driven and equipped with balance shafts.
4G30
The 4G30 displaces 1.3 L (1,289 cc). It is an 8-valve SOHC design with an aluminium head and iron block. The engine has five main bearings. Power was 87 hp.
Bore x Stroke: 2.87" x 3.03"
Applications
4G31
The 4G31 displaces 1.5 L (1,499 cc). It is an 8-valve SOHC design with an aluminium head and iron block. The engine has five main bearings. Power was 95-105 hp depending on which carburetor combo was used. An updated version with electronic central-point fuel injection was installed in Mirages and Lancers from 1986 on. A version for industrial use has 37 PS (27 kW) at 3000 rpm.
Bore x Stroke: 2.93" x 3.39"
Applications
4G32
In 1970, the 4G32 was introduced, and it displaces 1.6 L (1,597 cc). It is an eight-valve SOHC design with an aluminium head and iron block. The engine has five main bearings, a cross flow head and a single down draught carburetor. Firing order is 1-3-4-2. The GSR versions used two twin-barrel Mikuni-built Solex carburetors for a total of 110 hp (SAE).
A version with an early iteration of Mitsubishi's MCA lean-burn system (MCA-IIB), fulfilling the intermediate Japanese exhaust regulations for 1975, was called G32A. Those with the later, cleaner yet, "MCA-Jet" system were called G32B. Later, the G32B also came in a fuel injected, turbocharged model. For competition, a version of the 4G32 engine was made with a DOHC eight-valve cylinder head, and fitted with two twin-choke 40 mm Solex sidedraft carburettors.
Bore x Stroke: 3.03" x 3.39"
Applications:
4G32T
Turbocharged version of the 4G32.
4G33
The 4G33 displaces 1.4 L (1,439 cc) from a 73.0 x 86.0 mm bore and stroke. There was also an MCA-Jet equipped G33B developed to fulfill the 1978 Japanese emissions regulations.
Applications:
4G35
The 4G35 displaces 1.7 L (1,686 cc). It is an 8-valve SOHC design with an aluminium head and iron block. The engine has five main bearings. Power was 105-115 hp depending on which carburetor combo was used.
Bore x Stroke: 79.0 x 86.0 mm
Applications:
4G36
The 4G36 displaces 1.2 L (1,238 cc). 73.0 x 74.0 mm bore and stroke.
Applications:
4G37
The 8-valve SOHC 4G37 displaces 1.8 L (1,755 cc).
Bore x Stroke: 3.17in x 3.39in
Compression Ratio: 9.5:1
Applications:
By other brands:
6G34
The 6G34, referred to by Mitsubishi as the Saturn 6, is a 12-valve SOHC straight-6 of 2.0 L (1,994 cc) displacement.
The 6G34 was used only in the Mitsubishi Debonair Executive from September 1970 to June 1976, and saw very limited production. Effectively, the design was that of the standard Saturn four-cylinder block with two additional cylinders grafted on.
Applications: