Mitsubishi Saturn engine should not be confused with Saturn I4 engine.
| Mitsubishi Saturn engine | |
| Aka: | 4G3 |
| Manufacturer: | Mitsubishi Motors |
| Configuration: | Straight-4 & Straight-6 |
| Production: | 1969–1999 |
| Fueltype: | Gasoline |
| Fuelsystem: | Mikuni-built Solex carburetor Central-point EFI |
| Coolingsystem: | Water-cooled |
| Head: | Aluminium |
| Block: | Cast iron |
| Valvetrain: | SOHC & DOHC, 2 valves x cyl. |
| Turbocharger: | On G32B & 4G32T |
| Compression: | 9.5:1 |
| Displacement: | NaNcc |
| Bore: | 73mm 74.5mm 77mm 79mm 80.6mm |
| Stroke: | 74mm 77mm 86mm |
| Power: | NaN0NaN0 |
The Mitsubishi Saturn or 4G3 engine is series of overhead camshaft (OHC) straight-four internal combustion engines introduced by Mitsubishi Motors and saw first service in the 1969 Colt Galant. Displacement ranges from 1239to, although there was also a rare 1994cc inline-six version built from 1970 until 1976. The early versions have chain driven valvetrain while the later versions are belt driven and equipped with balance shafts.
The 4G30 displaces 1289cc. It is an 8-valve SOHC design with an aluminium head and iron block. The engine has five main bearings. Power was 87hp.
Bore x Stroke: NaNmm
The 4G31 displaces 1499cc. It is an 8-valve SOHC design with an aluminium head and iron block. The engine has five main bearings. Power was NaNhp depending on which carburetor combo was used. An updated version with central-point electronic fuel injection was installed in Mirages and Lancers from 1986 on.[1] A version for industrial use has 370NaN0 at 3000 rpm.
Bore x Stroke: NaNmm
In 1970, the 4G32 was introduced, and it displaces 1597cc. 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 110hp (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. This was built for less than one year, as the new MCA engine arrived in November 1975. 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 40mm Solex sidedraft carburettors.
Bore x Stroke: NaNmm
Turbocharged version of the 4G32.
The 4G3 displaces 1440cc from a NaNmm bore and stroke. There was also an MCA-Jet equipped G33B developed to fulfill the 1978 Japanese emissions regulations.
The 4G35 displaces 1686cc. It is an 8-valve SOHC design with an aluminium head and iron block. The engine has five main bearings. Power was NaNhp depending on which carburetor combo was used.
Bore x Stroke: NaNmm
Applications:
The 4G36 displaces 1239cc. NaNmm bore and stroke.
Applications:
The 8-valve SOHC 4G37 displaces 1755cc.
Bore x Stroke: NaNmm
Compression Ratio: 9.5:1
Applications:
By other brands:
The 6G34, referred to by Mitsubishi as the Saturn 6, is a 12-valve SOHC straight-6 of 1994cc 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 to replace the KE64.
Applications: