 | This article needs additional citations for verification. (January 2014) |
| Iron Duke | |
|---|---|
 | |
| Overview | |
| Manufacturer | General Motors |
| Also called | Tech IV (1982-1990) |
| Production | 1977–1993 |
| Layout | |
| Configuration | Straight-four |
| Displacement | 150.8 cu in (2.5 L) |
| Cylinder bore | 4 in (101.6 mm) |
| Piston stroke | 3 in (76.2 mm) |
| Cylinder block material | Cast iron |
| Cylinder head material | Cast iron |
| Valvetrain | OHV 2 valves x cyl. |
| Compression ratio | 8.25:1 (1977–1983) 9.0:1 (1984–1993) |
| RPM range | |
| Max. engine speed | 5000 rpm |
| Combustion | |
| Fuel system | Carburetor Throttle-body fuel injection |
| Fuel type | Gasoline |
| Oil system | Wet sump |
| Cooling system | Water-cooled |
| Output | |
| Power output | 85–110 hp (63–82 kW) |
| Specific power | 34.4 hp (25.7 kW)-44.5 hp (33.2 kW) per liter |
| Torque output | 123–135 lb⋅ft (167–183 N⋅m) |
| Dimensions | |
| Dry weight | 375 lb (170 kg)[1]: 3 |
| Chronology | |
| Predecessor | GM 2300 engine |
| Successor | GM 122 engine |
The Iron Duke engine (also called 151, 2500, Pontiac 2.5, and Tech IV) is a 151 cu in (2.5 L) straight-4 piston engine built by the Pontiac Motor Division of General Motors from 1977 until 1993. Originally developed as Pontiac's new economy car engine, it was used in a wide variety of vehicles across GM's lineup in the 1980s as well as supplied to American Motors Corporation (AMC). The engine was engineered for fuel efficiency, smooth operation, and long life, not for performance.[2] Total Duke engine production is estimated to be between 3.8 and 4.2 million units.[3]
- ^ Sawruk, John M. (26–30 September 1977). Pontiac's New 2.5 Litre 4 Cylinder Engine (PDF). Society of Automotive Engineers: Passenger Car Meeting. Detroit. Archived from the original (PDF) on 5 February 2018. Retrieved 17 August 2019.
- ^ Hunting, Benjamin (May 26, 2021). "GM's Unkillable Iron Duke 4-Cylinder Engine Powered Dozens Of Trucks, Cars, and SUVs For Decades". DrivingLine. Retrieved January 20, 2023.
- ^ Appel, Tom (September 12, 2018). "What Was The Iron Duke?". The Daily Drive by Consumer Guide. Retrieved January 20, 2023.