Mitsubishi Neptune engine

4G4
Overview
Manufacturer Mitsubishi Motors
Also called Neptune
Production 1971–1979
Combustion chamber
Cylinder block alloy Cast iron

The Mitsubishi Neptune or 4G4 engine is a series of iron-block OHV inline-four engines built by Mitsubishi Motors from 1971 to 1979, alongside the Orion, Saturn, Astron, and Sirius. This was to be Mitsubishi's last OHV engine. The inability to clear new emissions rules for 1978 meant that the Neptunes were replaced by the 4G1 Orion.

4G41

Displacement — 1,378 cc
Bore — 76.5 mm
Stroke — 75.0 mm
Compression ratio — 9.0:1
Power — 64 kW (87 PS) at 6,000 rpm
Torque — 115 Nm (85 lb·ft) at 4,000 rpm

Applications

4G42

Displacement — 1,187 cc
Bore — 71.0 mm
Stroke — 75.0 mm
Compression ratio — 9.0:1
Power — 51 kW (70 PS) SAE at 6,000 rpm
Torque — 95 Nm (9.7 kgm) at 4,000 rpm

Applications

See also