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]
| Neptune engine | |
|---|---|
| Overview | |
| Manufacturer | Mitsubishi Motors |
| Also called | 4G4 |
| Production | 1971–1981 |
| Layout | |
| Configuration | Inline-4 |
| Displacement | 1.2–1.4 L (1,188–1,378 cc) |
| Cylinder bore | 71 mm (2.8 in) 76.5 mm (3.01 in) |
| Piston stroke | 75 mm (2.95 in) |
| Cylinder block material | Cast iron |
| Valvetrain | OHV 2 valves x cyl. |
| Compression ratio | 9.0:1 |
| Combustion | |
| Fuel type | Gasoline |
| Cooling system | Water-cooled |
| Output | |
| Power output | 70–87 PS (51–64 kW; 69–86 hp) |
| Torque output | 9.7–11.7 kg⋅m (95–115 N⋅m; 70–85 lb⋅ft) |
| Chronology | |
| Predecessor | KE engine |
| Successor | 4G1 Orion |
4G41 edit
Displacement — 1.4 L (1,378 cc)
Bore x Stroke — 76.5 mm × 75 mm (3.01 in × 2.95 in)
Power — 86 PS (63 kW; 85 hp) at 6,000 rpm (single carb)
- 95 PS (70 kW; 94 hp) at 6,300 rpm (Galant FTO, twin carb)
- 28 PS (21 kW; 28 hp) at 2,700 rpm in a 1972 FG15 forklift[2]
- 95 PS (70 kW; 94 hp) at 6,300 rpm (Galant FTO, twin carb)
Torque — 11.7 kg⋅m (115 N⋅m; 85 lb⋅ft) at 4,000 rpm (single carb)
- 8.6 kg⋅m (84 N⋅m; 62 lb⋅ft) at 2,000 rpm in a 1972 FG15 forklift[2]
Applications edit
- Mitsubishi Galant
- 1971-1973 Mitsubishi Galant FTO
- 1971.10-1979.06 Mitsubishi Delica 75/1400[3]
- Mitsubishi Forklift FG14, FG15
4G42 edit
Displacement — 1.2 L (1,188 cc)[4]
Bore x Stroke — 71 mm × 75 mm (2.80 in × 2.95 in)
Power — 70 PS (51 kW; 69 hp) SAE at 6,000 rpm
Torque — 9.7 kg⋅m (95 N⋅m; 70 lb⋅ft) at 4,000 rpm
Applications edit
- 1973.02-1975.10 Mitsubishi Lancer A71A[4]
- 1973.09-1976.10 Mitsubishi Lancer Van A71V
See also edit
References edit
- ^ a b "1971: 4G4型（ネプチューン）エンジンの生産を開始" [1971: Started production of 4G4 (Neptune) engine]. 会社の歴史 _ 三菱自動車の歴史(沿革) [Company History: History of Mitsubishi Motors] (in Japanese). Mitsubishi Motors. Archived from the original on 2022-08-07.
- ^ a b 自動車ガイドブック: Japanese motor vehicles guide book 1972—73 (in Japanese), vol. 19, Japan: Japan Automobile Manufacturers Association, 1972-10-23, p. 294
- ^ Kazuhiko. 初代デリカ（Ｔ系） [First Delica (T-series)]. Delica History (in Japanese). Archived from the original on 21 July 2011.
- ^ a b Car Graphic: Car Archives Vol. 5, '70s Japanese Cars. Tokyo: Nigensha. 2007. p. 77. ISBN 978-4-544-09175-5.