| Neptune engine | |
| Aka: | 4G4 |
| Manufacturer: | Mitsubishi Motors |
| Configuration: | Inline-4 |
| Production: | 1971–1981 |
| Predecessor: | KE engine |
| Successor: | 4G1 Orion |
| Fueltype: | Gasoline |
| Coolingsystem: | Water-cooled |
| Compression: | 9.0:1 |
| Displacement: | NaNcc |
| Block: | Cast iron |
| Valvetrain: | OHV 2 valves x cyl. |
| Bore: | 71mm 76.5mm |
| Stroke: | 75mm |
| Power: | NaN0NaN0 |
| Torque: | NaN0NaN0 |
The Mitsubishi Neptune or 4G4 engine is a series of iron-block OHV inline-four engines built by Mitsubishi Motors from June 1971 to 1981.[1] This was to be Mitsubishi's last OHV engine. The inability to clear new passenger car emissions rules for 1978 meant that the Neptunes were replaced by the 4G1 Orion. The Neptune continued to be built until 1979 for commercial vehicles, which suffered less restrictive environmental regulations and until about 1981 for other applications. Around 520,000 Neptune engines were built.[1]
Displacement — 1378cc
Bore x Stroke — NaNmm
Power — at 6,000 rpm (single carb)
at 6,300 rpm (Galant FTO, twin carb)
at 2,700 rpm in a 1972 FG15 forkliftTorque — 11.70NaN0 at 4,000 rpm (single carb)
8.60NaN0 at 2,000 rpm in a 1972 FG15 forklift
Displacement — 1188cc[3]
Bore x Stroke — NaNmm
Power — 700NaN0 SAE at 6,000 rpm
Torque — 9.70NaN0 at 4,000 rpm