Chrysler 273 V8 -moottori oli merkittävä osa amerikkalaista autoteollisuutta 1960-luvulla. Se oli ensimmäinen Chrysler LA -sarjan moottori, joka esiteltiin vuonna 1964. Tämä moottori tarjosi kevyemmän ja tehokkaamman vaihtoehdon aiemmille A-sarjan moottoreille, ja se oli saatavilla useissa Plymouthin ja Dodgen malleissa.

Chrysler 273 V8 -moottorin tekniset tiedot

  • Iskutilavuus: 273 kuutiotuumaa (4,5 litraa)
  • Sylinterin mitat: Porauksen halkaisija 3,625 tuumaa (92,1 mm), iskun pituus 3,31 tuumaa (84,1 mm)
  • Teho: 180 hv (134 kW) vakiona; 235 hv (175 kW) Commando-versiossa; 275 hv (205 kW) D/Stock-versiossa
  • Puristussuhde: 10,5:1
  • Nokka-akseli: Valurautainen, mekaanisilla tai hydraulisilla nostimilla
  • Kampiakseli: Valettu tai taottu teräs
  • Mäntä: Valettu alumiini
  • Sylinterikannet: Kiilamaiset palotilat, yksi imu- ja yksi pakoventtiili per sylinteri
  • Sytytystulpat: Sijaitsevat sylinterikannen sivulla, pakokanavien välissä

Vuoteen 1968 asti moottorissa käytettiin mekaanisia nostimia, minkä jälkeen siirryttiin hydraulisiin nostimiin, jotka vähensivät venttiilikoneiston melua.

Suorituskykyiset versiot

273 Commando (1965–1967)

Commando-versio oli suunnattu suorituskykyä arvostaville kuljettajille. Se sisälsi nelikurkkuisen kaasuttimen, korkeamman noston ja pidemmän keston omaavan nokka-akselin, vahvemmat venttiilijouset sekä erityiset mustat venttiilikopat alumiinisilla koristeilla. Moottorin teho oli 235 hv (175 kW) ja vääntömomentti 280 lb-ft (380 Nm) .

D/Stock 273 (1966)

Vuonna 1966 esiteltiin erityinen D/Stock-versio, joka oli suunniteltu NHRA:n D-stock-luokan kiihdytyskilpailuihin. Tässä versiossa oli Holley 4-kurkkuinen kaasutin, 0,495" / 0,505" noston omaava nokka-akseli, viritetyt pakosarjat ja 10,5:1 puristussuhde. Teho oli 275 hv (205 kW) ja vääntömomentti 295 lb-ft (400 Nm) .en.wikipedia.org

Asennusajoneuvot

Chrysler 273 V8 -moottoria käytettiin laajasti eri malleissa vuosina 1964–1969. Se oli saatavilla seuraavissa ajoneuvoissa:

  • Plymouth Barracuda (1964–1969): Erityisesti Formula S -versiossa Commando-moottorilla.
  • Plymouth Valiant (1964–1969): Tarjolla valinnaisena moottorina.
  • Dodge Dart (1964–1969): Sisälsi myös D/Dart-erikoisversion vuonna 1966.
  • Plymouth Belvedere (1965–1967): 273 V8 -moottori oli saatavilla eri tehoversioina .

Viritysmahdollisuudet

273 V8 -moottori tarjoaa hyvät mahdollisuudet viritykseen:

  • Imusarja: Alumiininen imusarja (esim. Edelbrock) parantaa virtausta ja vähentää painoa.
  • Nokka-akseli: Mekaaniset nokka-akselit tarjoavat paremman suorituskyvyn; suosittuja vaihtoehtoja ovat Comp Camsin ja Hughes Enginesin mallit.
  • Sytytys: Mopar Performance -sähkösytytys parantaa kipinän voimakkuutta ja luotettavuutta.
  • Kaasutin: Holley 4160 tai 4150 -kaasuttimet tarjoavat paremman polttoaineen syötön; suositeltava koko enintään 650 CFM.

On tärkeää huomioida, että suuremman noston omaavat nokka-akselit vaativat vahvemmat venttiilijouset ja mahdollisesti sylinterikansien porttauksia optimaalisen suorituskyvyn saavuttamiseksi.

Yhteenveto

Chrysler 273 V8 -moottori oli merkittävä askel LA-sarjan kehityksessä, tarjoten kevyemmän ja tehokkaamman vaihtoehdon aiemmille moottoreille. Sen suorituskykyiset versiot, kuten Commando ja D/Stock, osoittivat moottorin potentiaalin kilpakäytössä. Vaikka se jäi myöhempien LA-sarjan moottoreiden, kuten 318:n ja 340:n, varjoon, 273 V8 on edelleen arvostettu moottori klassikkoautojen harrastajien keskuudessa.

273 Commando (erols.com)

The 273 Commando was available two ways in '66. The
standard 235 HP version and a D/Stock version rated at 275 HP.
The D/Stock version was available as both a limited production
factory option, and an over-the-counter dealer option in '66.
The option was intended to help the A body Mopars to compete in
the D/Stock class with an advertised LBS/HP ratio range of 10.6
to 11.29. The option, which was offered from the factory without
warranty, included a Holley 4160 carb, adapter plat, a 284 degree
.495" I/ .505" E lift cam and spring set, tuned headers dumping
into the stock exhaust, and, in the "D/Dart tested by Car Craft
in August of '66, a 4.86:1 8-3/4" sure grip 3rd member. As Car
Craft notes:
Straight "out of the box" so to
speak, the D/Dart turned 94.21
mph in 14.33 seconds which was
almost as fast as the street hemi,
our test car of a few months back.
The engine still had less than 150
miles on it...

I have also seen references to the under rating by the factory
of the 273 Commando's output (people have equated it with the
"K" code 289 Ford at 271 HP), and I won't disagree with that.
ITEMSPECIFICATION
Carburetor: 600 CFM AFB / Holley 4160 (D/Stock)
Bore: 3.625"
Stroke: 3.31"
Compression Ratio: 10.5:1
Cam:
 
 
  Lift Duration
  Intake Exhaust Intake Exhaust
Commando: 0.425" 0.425" 248° 248°
D/Stock: 0.495" 0.505" 284° 284°
Gross Horsepower: 235 @ 5200 RPM / 275 @ 6000 RPM (D/Stock)
Torque: 280 Ft/Lbs @ 4000 RPM / 295 Ft/Lbs @ 4400 RPM (D/Stock)
273 Commando

Some Hop-Up Ideas for the 273.
  • Aluminum Intake: the stock 273 intakes are heavy and don't
    flow all that well. An Edelbrock, Wyand, Ofenhauser, or
    MOPAR aluminum intake will save pounds, make more power,
    and improve drivability.

    One issue for 273s is that the angle and size of the intake
    bolts changed for the '66 model year. Later intakes can be
    adapted to the '64 and '65 273 by any good machinist or
    engine builder. The bolt holes have to be redrilled to
    the older angle and the bolt hole openings in the intake
    have to be re-spot faced to be normal (90°) to the bolt.
    The '64 and '65 intake bolts were 5/16" so you also need to
    use hardened washers under the intake bolt heads to take up
    the slack in the 3/8" bolt hole openings and maintain the
    proper torque on the early 5/16" bolts.

  • Cam: I don't recommend a hydraulic cam for the 273. The 273
    has mechanical valve gear and requires special shorter
    pushrods if you convert it to a hydraulic. Also you get a
    better performance bang for the buck with a mechanical cam.
    Here are some I like for the 273 Commando roughly in order
    of "hotness":
    CAM Lift I/E Dur I/E Tämä sähköpostiosoite on suojattu spamboteilta. Tarvitset JavaScript-tuen nähdäksesi sen." Lobe_Sep RPM_Range Min_Comp
    Competition Cams 270 S: 0.468"/0.468" 270°/270° 224°/224° 110° 1800-5800 9:1
    Comp Cams 20-233-4 XS268S: 0.488"/0.501" 268°/274° 230°/236° 110°    
    MOPAR Perf MOPP4529346: 0.490"/0.490" 276°/276° 235°/235° 112°    
    Competition Cams 282 S: 0.495"/0.495" 282°/282° 236°/236° 110° 3000-6000 9.5:1
    Hughes Engines HEV3945AS: 0.546"/0.560" 260°/277° 239°/245° 107° 2100-5900 9.5:1
    Comp Cams 20-230-4 XS274S: 0.502"/0.511" 274°/280° 236°/242° 110°    
    Edelbrock Performer RPM: 0.488"/0.510" 308°/318° 234°/244°      
    Comp Cams 20-231-4 XS282S: 0.520"/0.540" 282°/290° 244°/252° 110°    
    Hughes Engines HEV4550AS: 0.560"/0.575" 277°/283° 245°/250° 106° 2300-6300 9.75:1
    All these cams will require matched valve springs, and the
    ones with lift beyond 0.500" would REALLY benefit from
    some port work to take advantage of the higher lift they provide.
    Also most of these cams require at least 9.5:1 or more static
    compression to really work, so if your tuning up a 2 barrel
    273, be prepared to do some cylinder head milling. To get to 9.5:1
    with flat top pistons you need to mill the 57 CC 273 heads to 52 CC,
    assuming a 0.005" deck height and a 0.032" installed head gasket
    thickness.

  • Ignition: Convert to MOPAR Performance electronic ignition using the
    chrome control unit. The standard control unit will work fine
    in most cases but the chrome one provides a hotter spark from
    idle to 8,000 RPM.

  • Carburetor: For the street the stock AFB should be fine up to a point,
    but even Chrysler put a Holley on when they got serious. For
    auto trans cars use a vaccum secondary 4160, for manuals a 4150
    double pumper, no bigger than 650 CFM in both cases. Make sure
    your using a dual feed, center hung version of these Holleys or
    you'll have some of the same issues under hard cornering, braking,
    and acceleration that the AFB has. Holleys DO have a problem with
    flooding out under heavy braking here are the fixes (use ALL of
    them):
    • Use the long "dog whistle" float bowl vent baffles.
    • Install jet extensions on the rear (secondary)
      metering block.
    • Install a piece of fuel line between the bowl vents
      so that they are extended vertically an inch or so.
      Cut a small section out of the top of the fuel line's
      arc and punch a small hole for the air cleaner stud
      to pass through (a little insurance against it being
      inhaled).
  • Here is a more detailed listing of 273 Factory cam Spec's
                                  Intake     Exhaust
                                  ========   =======
             Std. 273 2 Brl (8.8:1):
                   Valve Lift:    0.395"     0.395"
                   Duration:      240ø       240ø
                   Opens:         14ø BTDC   58ø BBDC
                   Closes:        46ø ABDC    2ø ATDC
    
             273 Commando (10.5:1):
                   Valve Lift:    0.425"     0.425"
                   Duration:      248ø       248ø
                   Opens:         14ø BTDC   56ø BBDC
                   Closes:        54ø ABDC   12ø ATDC
    
             D/Stock 273 (10.5:1, Actually a Camcraft part):
                   Valve Lift:    0.495"     0.505"
                   Duration:      284ø       284ø
    
             SAE Gross Horsepower & Torque:
                    Std 273
                    ======================================
                    180 @ 4200 RPM & 260 Ft/lbs @ 1600 RPM
    
                    273 Commando
                    ======================================
                    235 @ 5200 RPM & 280 Ft/Lbs @ 4000 RPM
    
                    D/Stock 273
                    ======================================
                    275 @ 6000 RPM & 295 Ft/Lbs @ 4400 RPM
                                        


  • More to come...

Return to TOP document

 
Last Updated: 02/22/2004

n

273 V8[edit]

The 273 cu in (4.5 L) was the first LA engine, beginning model year 1964 and offered through 1969, rated at 180 hp (134 kW). It had a bore and stroke of 3.625 in × 3.31 in (92.1 mm × 84.1 mm). It had a mechanical solid lifter valvetrain until 1968 when hydraulic lifters were introduced; hydraulic lifters generally make for a quieter valvetrain. The reciprocating assembly included a cast or forged steel crankshaft, drop forged steel connecting rods and cast aluminum pistons. The valvetrain consisted of a cast nodular iron camshaft, solid or hydraulic lifters, solid pushrods and shaft-mounted, malleable iron rocker arms (stamped steel on later hydraulic-cam engines). These actuated the overhead steel intake and exhaust valves. The cylinder heads featured wedge-shaped combustion chambers with a single intake and a single exhaust valve for each cylinder. Spark plugs were located in the side of the cylinder head, between the exhaust ports.[2]

A high performance 235 hp (175 kW) was offered 1965-1967, this was standard in the Barracuda Formula S model and optional in all other compact models excluding station wagons. It featured a 4-bbl. carburetor and matching intake manifold, chrome unsilenced air cleaner with callout sticker, longer-duration and higher-lift camshaft and stronger valve springs, 10.5:1 compression ratio, and special black wrinkle valve covers with extruded aluminum appliques. It was fitted to a low-restriction exhaust system with a 2.5 in (64 mm) exhaust pipe, collector-type Y-junction, and exposed resonator. In 1965 (only) the muffler was of "straight through" construction.

A special version was also available in 1966 only - it used a 0.5 in (12.7 mm) lift solid-lifter camshaft, fabricated-steel-tube exhaust, and a Holley 4-barrel carburetor, producing 275 hp (205 kW) (1 hp/cu in). It was available in the Dodge Dart only, and the car so equipped was called the "D-Dart", a reference to its classification in NHRA D-stock for drag racing, which was the car's only intended purpose.

n