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Chrysler LA engine
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The LA engines are a family of pushrod OHV 90° V-block gasoline engines built by Chrysler Corporation and factory-installed in passenger vehicles, trucks and vans, commercial vehicles, marine and industrial applications from 1964 through 2003. The combustion chambers are wedge-shaped, rather than the polyspherical combustion chambers in the predecessor A engine or the hemispherical chambers in the Chrysler Hemi engine.
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Encyclopedia
The LA engines are a family of pushrod OHV 90° V-block gasoline engines built by Chrysler Corporation and factory-installed in passenger vehicles, trucks and vans, commercial vehicles, marine and industrial applications from 1964 through 2003. The combustion chambers are wedge-shaped, rather than the polyspherical combustion chambers in the predecessor A engine or the hemispherical chambers in the Chrysler Hemi engine. All are cast iron, except for the Viper V10, which is aluminum. LA engines have the same bore spacing as the A engines. LA engines were made at Chrysler's Mound Road Engine plant in Detroit, Michigan as well as plants in Canada and Mexico.
273 V8
The 273 (4.5 L) was the first LA engine, introduced in 1964 and offered through 1969, rated at 180 BHp. It had a 3.625 in (92 mm) bore and 3.31 in (84 mm) stroke. It had a mechanical solid lifter valvetrain until 1968 when hydraulic lifters were introduced. A special version was also available in 1966 only - it used a lift solid-lifter camshaft, fabricated-steel-tube exhaust, and a Holley 4-barrel carburetor, producing 275 horsepower (1 hp/cu in). It was available in the Dodge Dart only, and the car so equipped was called the "D-Dart". A version with a less aggressive camshaft and without the tube headers was available on regular production Darts, Valiants, and Barracudas from 1965 to '67, it was standard only in the Barracuda Formula S model.
318 V8
The LA 318 was a 318 cu in (5.2 L) relative of the A 318. Like the A 318, it has a larger bore at 3.91 in (99 mm) as well as a stroke of 3.31 in (84 mm). It appeared shortly after the 273, in 1967, and proved tremendously successful. A version of this engine was available until 1991 when its was superseded by the Magnum version (See below). It used hydraulic lifters and a two barrel carburetor for most of its production, though four-barrel Carter Thermo-Quad and Rochester Quadrajet carburetors were used in police applications starting in 1978. The 318 received roller lifters and a fast-burn cylinder head in 1985, and throttle-body electronic fuel injection for truck applications starting in 1988.
340 V8
As the Detroit power wars heated up in the mid-1960s, Chrysler decided to produce a small block V8 specifically designed for high performance applications. The goal was to have a lightweight, high output engine equally suited for the drag strip or an oval track. The result of this decision was the 340 cu in V8. Chrysler's engineers increased the 318's cylinder bores to while keeping the 318's stroke. Anticipating higher loads resulting from racing operation, the engineers fitted a forged steel crankshaft instead of the cast nodular iron unit used in the 318. A 4-barrel carburetor was mated to a high-rise, dual plane intake manifold. This induction setup fed into a set of cylinder heads that are still considered one of the best of that era. The heads were high-flow items with big ports, and used intake and exhaust valves. An aggressive cam was fitted to take advantage of the much better breathing top end. 1968 4-Speed cars got an even hotter cam, but it was discontinued in 1969. The engine was equipped with hydraulic lifters. Power output was officially stated as for the 4 barrel and for the 6-pack version with triple 2-barrel carburetors. Using flat-top pistons, the 340's compression ratio was 10.5:1, placing it near the limit of what was possible on pump gas. The 340 also used heavy-duty parts such as a dual timing chain, windage tray and revised oil pump.
In 1970, Chrysler offered a special version of the 340 for use in the Challenger TA and Cuda AAR. The "TA" engine featured a heavy duty short block featuring additional webbing in block to allow for 4 bolt main bearing caps, double roller timing chain and 10.5:1 compression. The heads featured larger ports compared to a standard 340 and offset rocker arms that allowed the pushrods to be moved away from the intake ports for improved airflow. They featured an aluminium intake manifold with three two barrel Holley carburetors and a dual points ignition system.
Like many other performance V8's of the day, for insurance reasons, the 340 engine's power output was officially understated. In reality, either the 4bbl or 6bbl configuration could produce at least 315 to 320 hp (235 to 239 kW). The 340 developed a reputation for outperforming much larger and heavier engines, with the attendant handling benefits provided by the relatively light-weight 340. The engine was praised as a high-revving unit with good durability, making it popular with circle-track racers.
Due to the combination of rising gas prices and insurance company crackdown on high-performance vehicles, the 340 did not stay in production long. It was released in 1968, detuned with lower compression and smaller 1.88 inch intake valves in 1972, and was withdrawn from production after the 1973 model year.
This engine also powered the French Monica 560.
360 V8
The LA 360 (5.9 L) has a 4.00 in bore and a 3.58 in stroke. It was released in 1971 with a two barrel carburetor. The 360 used the large intake port 340 heads with a smaller intake valve (1.88 inch). In 1973, a 4-barrel version was released. In 1974, the 360 became the most powerful LA engine with the end of 340 production. After 1980, the 360 was no longer used in cars, but only in the Dodge Ram trucks and vans. The 1978-1979 Lil' Red Express truck used a special high performance 360 4-barrel engine, with factory production code EH1. The EH1 was a modified version of the E58 360 police engine (E58) producing net @ 3800 rpm. Some prototypes for the EH1 featured Mopar Performance W2 heads, although the production units had the standard 360 heads. The 360 was replaced for 2003 with the 5.7 L Hemi.
239 V6
The 239 V6 is a 239 cu in (3.9 L) V6 released in 1987 for use in the Dodge Dakota. It is essentially a six-cylinder version of — the 318 V8 Output was 125 hp (93 kW) and torque until it was replaced by the Magnum 3.9 starting in 1992. In 1987 it used a two barrel Holley carb with hydraulic lifters. In 1988 it was upgraded to TBI and roller lifters which it retained until 92.
Magnum engines
The LA family was updated and branded as the Magnum V6 and V8 in 1992.
While the Magnum 3.9, Magnum 5.2, and Magnum 5.9 (1993-up) engines were significantly based on the 239, the 318, and the 360 — respectively — many of the parts will not directly interchange and are not technically LA engines (the only parts that are actually unchanged are the crankshafts and connecting rods). Magnum cylinder heads use a different oiling system and individually mounted rocker arms (AMC style) and a CCW rotation water pump with a much improved housing. The intake manifolds share basic dimensions but will not interchange without modifications. Chrysler's engineers redesigned the oil seals on the crankshaft to improve anti-leak seal performance. Although the pre-Magnum ('71-'92) and Magnum versions of the 360/5.9 are both externally balanced, the two are balanced differently (the 360 Magnum uses lighter pistons) and each requires a uniquely balanced damper, flywheel, drive plate, or torque converter. The valve covers on the Magnum have 10 bolts rather than the previous 5, for improved oil sealing.
Chrysler offers a line of crate engines based on the Magnum designed to bolt into older muscle cars and street rods with little modification. Some of the changes to facilitate this were using a 1970-93 water pump so that older pulleys and brackets could be used, as well as an intake manifold that uses a carburetor instead of fuel injection. With a high lift cam and single plane intake, the crate Magnum 360 was rated at with the Magnum heads. Later models equipped with "R/T" or aluminum cylinder heads produced . A 425-HP bolt-in fuel injection conversion kit is also available.
Magnum 5.2
The Magnum 5.2, released in 1992, was an evolutionary development of the 318 with the same displacement. The Magnum development included the multiport fuel injection, new cylinder heads with a closed combustion chamber, a new higher-flow valve angle, increased valve lift, and new intake and exhaust manifolds. Power was up to and . Production of the Magnum 5.2 ended with the 2003 model year Dodge Ram Van. It was replaced by the new 4.7 L PowerTech V8.
Magnum 5.9
The Magnum 5.9 is an evolution of the 360. It got the Magnum V8 name with the same new manifolds, heads, and fuel injection as the 5.2 for 1993. Engine output that year was and 325 lb·ft . The engine eventually produced and 345 lb·ft on the version used in the Dakota RT. Starting in 2003, the 5.7 L Hemi V8 began replacing this engine.
Magnum 3.9
The V6, like the 5.2 and 5.9 V8s, received the new Magnum cylinder heads, induction and engine management system as well as the Magnum name in 1992. Power increased substantially to 180 hp (134 kW)and from to . In 1994 the exhaust manifolds for this engine were reduced in size to save money. This reduced the engine's output to , but it retained its torque rating which later grew to . This engine was last produced for the 2003 Dodge Dakota pickup. Starting in the 2004 model year it was entirely withdrawn from production and replaced with the 3.7 L PowerTech V6 engine.
8.0 Viper V10
The Viper V10 is based on the rest of the LA family, and appeared with the Dodge Viper in 1992. It was conceived and prototyped as a Magnum 5.9 with two extra cylinders and a longer stroke of 3.88 in (99 mm).
Originally designed as a truck engine, Chrysler engineers revamped Dodge's cast-iron block V10 for the Viper by recasting the block and heads in aluminium alloy. Prototype blocks were cast by Lamborghini, at the time a Chrysler division. Some felt that the pushrod two-valve design, while adequate for the truck application for which the engine was originally created, was unsuitable for a performance car. However, Chrysler was uncertain about the Viper's production costs and sales potential and so declined to provide the budget for the modification.
The first-generation Viper V10 engine has a displacement of 8.0 L (488 cu in) and produces and . The second-generation engine, also displacing 8.0 L, produced and . The third-generation engine, introduced on the 2003 Viper, has a displacement of 8.3 L (505 cu in) and produces and . On January 8, 2007 Dodge released information at the Detroit Auto Show that the 2008 Dodge Viper engine's output would increase to and via a slight displacement increase to 8.4 L (510 cu in) and the use of variable valve timing, a first on a pushrod engine.
Production of the V10 engine started at Mound Road Engine before moving to Conner Avenue Assembly, where the Viper itself is built, in May 2001. In addition, the Viper V10 was installed in the Dodge Ram SRT-10, earning the truck the Guinness World Record for fastest production truck (later bettered by an Australian production car; the Holden HSV Maloo that uses the LS2 Corvette engine). The Dodge Tomahawk concept motorcycle also uses this engine.
The V10 is also sold to British luxury car manufacturer Bristol Cars. The Bristol Fighter is powered by a front-mounted V10, modified to produce . In the more powerful Fighter S the engine is tuned to give 628 hp (660 hp at high speed using the ram air effect). Bristol has recently announced the Fighter T, in which the V10 is further modified to produce .
Magnum V10
Originally conceived in the 1980s as a truck engine for the larger Rams, the Magnum V10 was re-engineered as the engine of the Dodge Viper in 1990 by Chrysler Engineering, and used in the Ram 2500 starting in the 1994 redesign of the Ram line. It provided far less power than the V10 in the Viper and used a cast-iron cylinder block. Output was and . It was discontinued after the 2003 model year.
See also
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