Editing Iron Duke engine (section)

{{about|the automobile engine|the steam locomotive|GWR Iron Duke Class}}
{{Infobox automobile engine
| image = Iron Duke^ 2.5L four cylinder engine - Flickr - dave 7.jpg
| name = Iron Duke
| aka = Tech IV (1982-1990)
| manufacturer = [[General Motors]]
| production = 1977–1993
| predecessor = [[GM 2300 engine]]
| successor = [[GM 122 engine]]
| bore = {{cvt|4|in|mm|1}}
| stroke = {{cvt|3|in|mm|1}}
| configuration = [[Straight-four]]
| displacement = {{cvt|2471|cc|CID L cc|1|adj=ri0|order=out}}
| length = 
| width = 
| height = 
| weight = {{cvt|375|lb|kg}}<ref name="SAE770819">{{cite conference |last=Sawruk |first=John M. |title=Pontiac's New 2.5 Litre 4 Cylinder Engine |conference=Society of Automotive Engineers: Passenger Car Meeting |date=26–30 September 1977 |location=Detroit |url= https://gafiero.akroncdnr.com/docs/IronDuke.pdf |access-date=17 August 2019 |archive-url= https://web.archive.org/web/20180205132841/https://gafiero.akroncdnr.com/docs/IronDuke.pdf |archive-date=5 February 2018}}</ref>{{rp|3}}
| block = [[Cast iron]]
| head = [[Cast iron]]
| valvetrain = [[Overhead valve engine|OHV]] 2 valves x cyl.
| fuelsystem = [[Carburetor]]<br/>[[Throttle-body fuel injection]]
| fueltype = [[Gasoline]]
| oilsystem = [[Wet sump]]
| coolingsystem = [[Radiator (engine cooling)|Water-cooled]]
| power = {{cvt|85–110|hp|kW|0}}
| specpower = {{cvt|{{#expr:85/2.471 round 1}}|hp|kW|1}}-{{cvt|{{#expr:110/2.471 round 1}}|hp|kW|1}} per liter
| torque = {{cvt|123–135|lbft|Nm|0}}
| compression = 8.25:1 (1977–1983) 9.0:1 (1984–1993)
| redline = 5000&nbsp;rpm
}}

The '''Iron Duke engine''' (also called '''151''', '''2500''', '''Pontiac 2.5''', and '''Tech IV''') is a {{cvt|151|cuin|L|1}} [[straight-4]] [[piston engine]] built by the [[Pontiac (automobile)|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.<ref>{{cite web |last1=Hunting |first1=Benjamin |title=GM's Unkillable Iron Duke 4-Cylinder Engine Powered Dozens Of Trucks, Cars, and SUVs For Decades |date=May 26, 2021 |url= https://www.drivingline.com/articles/gms-unkillable-iron-duke-engine-powered-dozens-of-trucks-cars-and-suvs-for-decades/ |work=DrivingLine |access-date=January 20, 2023}}</ref> Total Duke engine production is estimated to be between 3.8 and 4.2 million units.<ref>{{cite web |last1=Appel |first1=Tom |title=What Was The Iron Duke? |url= https://blog.consumerguide.com/what-was-the-iron-duke/ |work=The Daily Drive by Consumer Guide |access-date=January 20, 2023 |date=September 12, 2018}}</ref>

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