View source for Chevrolet 2300 engine

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{{Infobox automobile engine
| name          = Chevrolet 2300 engine
| image         = Vega 140 engine.jpg
| caption       = 
| manufacturer  = [[Chevrolet]] division of [[General Motors|GM]]
| aka           = Dura-Built 140
| production    = 1971–1977
| predecessor   = [[Chevrolet 153 4-cylinder engine]]
| successor     = [[GM Iron Duke engine]]
| configuration = [[Naturally aspirated]] [[Straight-four engine|I4]]
| displacement  = {{cvt|2287|cc|L cuin|1|order=flip}}
| bore          = {{cvt|3.501|in|mm|1}}
| stroke        = {{cvt|3.625|in|mm|1}}
| block         = [[Aluminum]]
| head          = [[Cast iron]]
| valvetrain    = [[Single overhead camshaft|SOHC]] 2 valves x cyl.
| compression   = 8.0:1
| fuelsystem    = Single or double barrel [[carburetor]]
| fueltype      = [[Gasoline]]
| oilsystem     = [[Wet sump]]
| coolingsystem = [[Radiator (engine cooling)|Water-cooled]]
| power         = {{cvt|70–110|hp|0}}
| specpower     = 
| torque        = {{cvt|107–138|lbft|Nm|0}}
| length        = 
| width         = 
| height        = 
| weight        = 
}}

The '''Chevrolet 2300''' is a 2.3-liter [[straight-four engine]] produced by the [[Chevrolet]] division of [[General Motors]] for the 1971 to 1977 model years of the [[Chevrolet Vega]] and [[Chevrolet Monza]]. This engine was also offered in the 1973–74 [[Pontiac Astre]] (Canada only), the 1975–77 Pontiac Astre (United States and Canada), the [[Pontiac Sunbird]] for 1976 only, and the [[Oldsmobile Starfire]] for 1976–77.

==Overview==
The engine features a die-cast [[cylinder block]] made of an [[aluminum alloy]] with 17% [[silicon]]. During the machining process, the cylinders were etched leaving the pure silicon particles exposed providing the piston wear surface and eliminating the need for iron cylinder liners. The block has cast iron main caps and a cast iron [[crankshaft]]. The engine's [[cylinder head]] is cast iron for lower cost, structural integrity and longer [[camshaft]] [[Bearing (mechanical)|bearing]] life. The valvetrain features a direct-acting [[single overhead camshaft]] design.<ref name="ahm-nov2005">{{cite web |url=http://www.athomemechanic.com/archives/2005/11/weird_gm_engine.html |title=Weird GM engines |date=5 November 2005 |publisher= |access-date=2024-10-23 |archive-url=https://web.archive.org/web/20120220132225/http://www.athomemechanic.com/archives/2005/11/weird_gm_engine.html |archive-date=2012-02-20 }}</ref> The engine block and cylinder heads were cast at [[Massena Castings Plant]] in [[Massena, New York]].

The tall, long-stroke engine's vibration tendencies are damped by large rubber engine mounts. One- and two-barrel carburetor versions were offered. The two-barrel L11 option also included a revised camshaft for a power increase of {{cvt|20|hp|kW|0}}. Bore × stroke are {{convert|3.501| × |3.625|in|mm|1}}, and compression is 8.0:1.

Overheating was a serious concern for the engine, since the engine block was of an open-deck design, severe overheating could cause the cylinder barrels to warp and pull away from the head gasket, causing coolant leaks into the cylinders and cylinder scuffing. Maintaining oil and coolant levels was crucial for the engine. The engine was equipped with an oil pressure switch which open circuits the electric fuel pump should the oil pressure fall below {{cvt|6|psi|bar}} during operation, stopping the engine and preventing it from being restarted until the oil level was replenished or the mechanical cause of low-oil pressure was remedied. Chevrolet dealers installed a coolant-recovery tank, a low-coolant warning light and extended Vega's engine warranty to {{convert|50000|mi}}.

The 1976 to 1977 the engine received a new cylinder-head design, incorporating hydraulic lifters to replace the taper-screw valve adjusters, improved coolant pathways, longer-life valve-stem seals, a redesigned water pump and thermostat, and a five-year, {{convert|60000|mi|km|adj=on}} engine warranty. The engine's name was changed to '''Dura-Built 140'''.

1975 to 1977 Pontiac Astres and 1975 to 1977 Chevrolet Monzas had the Vega engine as standard equipment. Of the Monza's [[H-body]] variants, the Pontiac Sunbird adopted Vega's revised Dura-built 140 engine for 1976 only, while the [[Oldsmobile Starfire]] offered it 1976-77.

The [[Cosworth#Road Engine Division / Cosworth Technology / MAHLE Powertrain|Cosworth]] Vega engine was produced in 1975 and 1976 using the 2300 engine block. The engine was de-stroked to {{convert|3.16|in|mm}} giving {{cvt|1994|cc|L cuin|1|order=flip}}, with a 16-valve aluminum cylinder head, double overhead cams ([[DOHC]]), [[forging|forged]] components and solid [[tappet|lifters]]. It produced {{cvt|110|hp|0}} and {{cvt|107|lbft|Nm|0}}.

==Aluminum engine block==
[[File:Vega block cylinder bores.jpg|thumb|left|Aluminum block has 17% [[silicon]] content, free standing siamese cylinder walls]]

GM Research Labs had been working on a sleeveless aluminum block since the late '50s. The incentive was cost. Engineering out the four-cylinder's block liners would save $8 per unit &mdash; a substantial amount of money at the time. [[Reynolds Group Holdings|Reynolds Metal Co.]] developed a [[Eutectic system|hypereutectic]] aluminum alloy called A-390, composed of 77% aluminum, 17% [[silicon]], 4% [[copper]], 1% [[iron]], and traces of [[phosphorus]], [[zinc]], [[manganese]], and [[titanium]]. The A-390 alloy was suitable for faster production [[diecasting]] which made the Vega block less expensive to manufacture than other aluminum engines. [[SPX Corporation|Sealed Power Corp.]] developed special chrome-plated [[piston rings]] for the engine that were blunted to prevent scuffing. Basic work had been done under Eudell Jackobson of GM engineering, but final production engineering work was finished by Chevrolet.

The Vega engine block was cast in [[Massena (town), New York|Massena, New York]], at the same factory that had produced the [[Chevrolet Turbo-Air 6 engine]] for the [[Chevrolet Corvair|Corvair]]. Molten aluminum was transported from Reynolds and [[Alcoa]] reduction plants to the foundry, inside Thermos-like insulated tank trailers from the factory across the street. The block was cast using the ACCURAD process. The casting process provided a uniform distribution of fine primary [[silicon|silicon particles]] approximately {{convert|0.001|in|um}} in size. Pure silicon provides a hard scuff and wear resistant surface, having a rating of 7 on the [[mohs scale]] of hardness, the same as [[quartz]], as compared to [[diamond]] which is 10. The blocks were aged 8 hours at {{cvt|450|°F|°C}} to achieve dimensional stability. The technical breakthroughs of the block lay in the precision die-casting method used to produce it, and in the silicon alloying which provided a compatible bore surface without liners. Before being shipped to [[List of GM factories|Tonawanda]], the blocks were impregnated with [[sodium silicate]], where they were machined through the outer skin.<ref name="ReferenceA">Collectable Automobile-April 2000</ref>
From Massena, the cast engine blocks were shipped as raw castings to Chevy's [[Tonawanda Engine]] plant in [[Tonawanda (town), New York|Tonawanda, New York]]. Here they underwent the messy etch and machining operations. The cylinder bores were rough and finish-honed conventionally to a {{convert|7|uin|adj=on}} finish then etched by a then-new electro-chemical process. The etching removed approximately {{convert|0.00015|in|um|adj=on}} of aluminum leaving the pure silicon particles prominent to form the bore surface.

[[File:Vega engine block cylinder bore.jpg|left|thumb|Silicon cylinder bore magnified 680 times]]
[[File:Vega engine piston plating.jpg|thumb|Four-layer electro-plated piston skirts]]

With a finished weight of {{convert|36|lb}}, the block weighs {{convert|51|lb}} less than the cast-iron block in the [[Chevrolet Nova#First/Second generation|Chevy II]] {{cvt|153|CID|L|1}} inline-4. Plating the [[piston]] skirts was necessary to put a hard iron skirt surface opposite the silicon of the block to prevent scuffing. The plating was a four layer electro-plating process. The first plate was a flash of zinc followed by a very thin flash of copper. The third and primary coating was hard iron, {{cvt|0.0007|in|um|adj=on}} thick. The final layer was a flash of tin. The zinc and copper were necessary to adhere the iron while the tin prevented corrosion before assembly of the piston into the engine. Piston plating was done on a 46 operation automatic line. From [[Tonawanda Engine|Tonawanda]], the engines went to the Chevrolet assembly plant in [[Lordstown, Ohio]].

Eudell Jackobson of GM engineering pointed out one of the early problems with unexplained scuffing and discovered excessive pressure on the bore hones was causing the silicon to crack. This need to both develop and actually manufacture the engine was a product of the program schedule. He said, "...We were trying to put a product into production and learning the technology simultaneously. And the pressure becomes very, very great when that happens. The hone-pressure problem was solved before engines actually went out the door, affecting pre-production engines only."<ref name="ReferenceA"/>

[[File:Vega 140 engine 3-speed manual.jpg|thumb|Chevrolet 2300 engine with 3-speed manual]]
{| class=wikitable
!rowspan=3|Year
!colspan=4|1 barrel
!colspan=4|2 barrel
|-
!colspan=2|power
!colspan=2|torque
!colspan=2|power
!colspan=2|torque
|-
!hp!!kW!!lb·ft!!N·m
!hp!!kW!!lb·ft!!N·m
|-
!1971
|''90''||''67''
|''136''||''184''
|''110''||''82''
|''138''||''187''
|-
!1972
|80||60
|121||164
|90||67
|121||164
|-
!1973
|75||56
|115||156
|85||63
|122||165
|-
!1974
|75||56
|115||156
|85||63
|122||165
|-
!1975
|78||58
|120||163
|87||65
|122||165
|-
!1976
|70||52
|107||145
|84||63
|113||153
|-
!1977
| ||
| ||
|84||63
|117||159
|-
|colspan=9|'''Note:''' Entries in italics are [[SAE International|SAE]] gross power values.
|}

==See also==
*[[GM engines]]

==References==
{{Reflist}}

==Further reading==
* {{cite magazine |last=Bond |first=John R. |date=July 1970 |title=The Next Generation |url=https://archive.org/details/car-life-1970-07/page/n11/mode/2up |magazine=[[Car Life (magazine)|Car Life]] |pages=10–14 |location= |publisher= |access-date=}}
* {{cite journal |last1=Kneisler |first1=Frederick J. |last2=Martens |first2=David A. |last3=Midgley |first3=Roy W. |date=1971 |title=The Vega 2300 Engine |url=https://www.jstor.org/stable/44731387 |journal=SAE Transactions |volume=80 |number=1 |publisher=[[SAE International]] |pages=520–545 |doi= |jstor=44731387 |access-date=}}
* {{cite journal |last1=Reuss |first1=L. E. |last2=Hughes |first2=C. N. |date=1971 |title=Vega 2300 |url=https://www.jstor.org/stable/44731389 |journal=SAE Transactions |volume=80 |number=1 |publisher=[[SAE International]] |pages=577–610 |doi= |jstor=44731389 |access-date=}}
* {{cite magazine |last=Macklin Jr. |first=Harold M. |date=1971-05-01 |title=Anatomy and Development of Aluminum Cylinder Block |url=https://www.ai-online.com/100-years-issue/?lib=527 |magazine=[[Automotive Industries (magazine)|Automotive Industries]] |pages=42–48 |location= |publisher=[[Chilton Company]] |access-date=}}

[[Category:Chevrolet engines]]
[[Category:Straight-four engines]]
[[Category:Gasoline engines by model]]