Monday, September 29, 2008

History of Toyota 4AGE Engine

The ‘A’ family of engines is unlike the very first Toyota type A engine. Toyota first completed the type A engine in September of 1934. It was a 3.4 liter, 6 cylinder, reverse engineered Chevrolet power plant. Today’s ‘A’ family of engines was and still is a successful and versatile 4 cylinder over head camshaft mass production power plant. The ‘A’ family beginning was humble but was the foundation for Toyota to start its “New Generation” of compact, lightweight, powerful and efficient power plants during the early 80’s. The ‘A’ family was used as part of the bases to start Toyota’s “Second” Generation of sport type engines.

The first generation sport type engines were the 3M, 5M-GE, 6M-GE series; the 9R, 8R-G (10R), 18R-G, 18R-GE, and the 2T-G, 2T-GE and 3T-GE series.

4AGE 16V Engine

Toyota’s first sport-type twin-cam engine was the 3M-type, which debuted with the Toyota 2000GT in 1967. Since then Toyota has taken high-performance DOHC (Double Over Head Cam) engines out of the realm of enthusiast-only sports driving, and put them within reach of more drivers with the 9R-type, the 10R-type, the 2T-G type, and the 18R-G type.

The oil crises of the 70’s and stringent emissions control regulations were a watershed event as far as twin-cam engines were concerned. However, Toyota called upon a considerable accumulation of technology and know-how as well as a concentrated R&D effort to continue the mass production of twin-cam engines.

In order to restore losses in engine output and response resulting from the emissions control measures instituted in Japan and the US around the mid 70’s and to exceed the earlier levels of engine capability and performance, Toyota introduced the “New Generation” series beginning with the 1G inline 6 series followed by the 4A-G series. The 4A-G is a direct decedent of the 1A engine, introduced in 1978 and progressed to the multi-valve engines of 1982.

In 1982, Toyota introduced the 1G-GE twin-cam engine, which was the start of the New generation (“second generation”) of Toyota 4 valve per cylinder sport type engines. This new engine had four valves per cylinder, technology which until then had been confined to the racing circuit. The technology achieved in the 1G-GE gave birth to a whole new generation of Toyota twin-cam engines. Furthermore, as twin-cam engines became run of the mill, Toyota countered with turbocharged models like the 3T-TGE in 1982, the twin-turbocharged 1G-GTE in 1985 and Japan’s most powerful engine of 1988 the 7M-GTE (mounted in the Supra Turbo A cars).

In 1985 Toyota introduced Japan’s first supercharged engine, the 1G-GZE and the year after, the 4A-GZE, mounting the SC12 supercharger.

The “second” generation of Toyota engines was developed in anticipation of the diversified and advanced needs of a new generation of automobile enthusiasts. These engines adopted advanced engine technologies developed for emissions controls, low fuel consumption, lightweight and compact design. Toyota’s goal was not only to enhance power but to have engines with quick response, low noise, and maintenance-free operation. Toyota further advanced the basic concept of comfort with what an engine should sound like.

Beginning in 1982 Toyota began mass producing 4-valve engines as part of its second-generation twin cam engine program. The 1G-GE and the 4A-GE were the start of the new configuration sport type engines. At that time they were said to be “high–output, quick-response yet fuel-efficient engines that bring the kind of appeal that’s not seen in conventional engines.” At the same time Toyota moved into the high-efficiency models as well.

The biggest differences between the (then) new high-efficiency twin cam 4-valve engines (designated as “F”), the conventional base engines and the “sports-type twin-cam” engines (designated as “G”) are the compact 4-valve head. This allows the engine’s to have superiority in overall efficiency, and in performance in everyday-use rpm ranges.

4AGE 20V Engine Silvertop

High-efficiency engines emphasize efficiency, throttle response, torque and practicality. Where, sports-type twin-cam engines are high performance machines that emphasize high-end power with high output and RPM and quick response. Thus Toyota has taken the sophisticated twin-cam 4-valve mechanism and put it to two different uses. This, Toyota reasoned, was better to serve a wider scope of user needs.

In 1989 Toyota was selected as the major sponsor for the Formula Atlantic race series along with Toyota Racing Development (TRD-USA) being selected as the official engine supplier. Thus the Cosworth engine was replaced. The Formula Atlantic cars are open wheeled, open cockpit race machines primarily for up and coming stars of the likes of father and son, Gilles and Jacques Villeneuve, Bertil Roos, Elliott Forbes-Robinson, Bobby Rahal, Keke Rosberg to name but just a few. Up until that time, the formula ran Cosworth Ford’s BDA (BDD) (Belt driven) engines that was apart of the “old” Formula B program and similarly configured for FIA’s Formula Mondiale. The engine selected was a modification of the venerable 4A-G, 1600cc, twin overhead cam, 4 valve per cylinder power plant. In 1994 improvements to the engine was approved, which included the use of electronic controlled fuel injection.

Contrary to a false assumption that the 4A-G is a copy of the Cosworth BDA, (coincidental ‘A’ series designation on both engines). There are little, if any, interchangeable parts between the two engines, outside of maybe some nuts and bolts. The Cosworth 4-valve design started life using the Ford Cortina engine block, with its distributor located on the side of the block and progressed to belt driven Escort engines. The basic block was, like the current formula Atlantic engine, based on a production block. Most of the Ford blocks that Cosworth used could be taken up to 2 liters. The 4A-G is limited to around 1.6 liters maximum, because of the deck height and bore spacing. The included valve angles for the BDA is 40°, along with what has become a Ken Duckworth design feature, and that is the use of a separate camshaft tray. To the contrary, the 4A-G has a one-piece head with the camshaft saddles cast right in. The included valve for the 4A-G is 50°, more similar to the earlier Alfas or other Italian designs of the 70’s.

The ‘A’ family of engines was designed as an over head cam power plant. The compact, thin cast iron block has served Toyota as a very versatile foundation for its engine evolution that is still in production.

4AGE 20V Engine Blactop

Toyota’s sport-type twin-cam engines utilize a DOHC 4-valve per-cylinder configuration, but it is a very simple and reliable one. The camshafts act directly on the valves (through the shim and follower) using the same principle that was employed on Salmson racing engines of 1927. The increase intake and exhaust valve area of a four-valve design improves the volumetric efficiency, and the lighter weight of the valve train allows higher-revs. As Toyota’s sports-type engines should be, these engines are designed and built for high output and quick response.

Unlike Toyota’s high-efficiency “F” type engines, the sports “G” type have a wide valve included angle, which improves the intake and exhaust flow, especially during high-volume gas flow. Further, the pentroof combustion chambers and centered spark plugs assure superior combustion characteristics, which means that a high compression ratio can be used. As the engine is designed for high-rev, high-output operation, its components are generally stronger than those of the high-efficiency engines.

4AGZE 16V Super Chager Engine

For its day, high power was not Toyota’s only major characteristic defining its sports-type twin-cam engines. Low friction loss and improved combustion combined to result in excellent fuel economy. Furthermore, the simplicity of the valve-train mechanism resulted in superior reliability as well as ease of maintenance. These engines were high-performance power plants that rate high in practicality and still do even after the turn of the century.

Another technical feature that came as a result of Toyota looking for performance improvements with out sacrificing low-end streetablity was the use of a variable induction system. The Toyota Variable Induction System (TVIS) boosts torque output across the rpm range and is calibrated to react to driving conditions. Its introduction coincided with the 4A-G.

In 1989 Toyota had three engine production plants, Shimoyama , Kamigo and Tahara. Since the high-efficiency twin cam engines, 4A-FE, 4A-F, 5A-F, 5A-FE and 1G-FE were produced in the Shimoyama plant, it is assumed that the sports-type 4A-Gs were built along side. Since that time, Toyota has many more engine production facilities around the world, with 7A engine blocks and cranks being manufactured in the UK (Toyota Motors Manufacturing, TMUK), and shipping them to Japan. TMUK is also shipping 4A engines to Turkey. While Australia, TMMCA (Toyota Motor Manufacturing Co. Australia) is producing 4A engines and shipping them to New Zealand. Moreover China, TTME, (Tianjin Toyota Motor Engine Co. Ltd) is producing 5A engines and is also shipping them to Japan.

4A-G Engine Codes
Every Toyota “engine type” has a code consisting of numbers and letters. An “engine type” may actually be a family of engines spanning several design generations and encompassing different specifications or components.

The first character is always a number followed by one or two letters. The number indicates the generation. The letter(s) indicates the engine family.

Following the engine generation and family codes, there are different combinations of additional letters, each of which represent a specific engine characteristic:

C - Equipped with emissions control systems (note: The “C” is not used if the engine was originally equipped for emissions controls.)(The C notation has been associated with California’s (USA), at that time having stricter emission standards)
U - Equipped with emissions control systems for Japan. (The U notation has been associated with the introduction of Unleaded fuel available in Japan at that time)
E - Electronic fuel injection (EFI)
F - Gear coupled cam drive; dual overhead cam (DOHC) engine: timing belt or chain drives one cam, and “scissors” gear drives the other cam. [Narrow included valve angle]. The split “scissors” gear is a unique way to eliminate gear backlash.
G - Dual overhead cam (DOHC) engine: timing belt or chain drives both cams. [Wide included valve angel]
L - Transversely mounted in vehicle
T - Turbocharged
Z - Supercharged


4A - SOHC, 8 valves
4A-C - SOHC, 8-valves, equipped with emissions control system
4A-LC - SOHC, 8-valve, transversely mounted, equipped with emissions control system
4A-GE - DOHC, 16-valve, fuel injected
4A-GEC - DOHC, 16-valve, fuel injected, equipped with emissions control system
4A-GELC - DOHC, 16-valve, fuel injected, transversely mounted, equipped with emissions control system
4A-F - DOHC, 16-valve, gear coupled cam drive, carbureted
4A-FE - DOHC, 16-valve, gear coupled cam drive, fuel injected
4A-ELU - DOHC, 16-valve, gear coupled cam drive, fuel injected, transversely mounted, equipped with emissions control system for Japan.
4A-GZE - DOHC, 16-valve, supercharged and fuel injected

The “A” block series is a versatile engine that has undergone many revisions.
The 1A-C started out as a 4-cylinder, SOHC, 1.5 liter carbureted engine which was introduced in the 1980 Tercel. It was upgraded in 1981 to the 3A-C. Changes to the cylinder head improved emissions control and performance. The 4A, introduced in the 1983 Corolla line, featured an increased displacement to 1.6 liters. It was available in several variations including the 4A-C, (SOHC, carbureted), the 4A-GE (DOHC 16 valve head, fuel injected), and the 4A-GZE (DOHC 16-valve head, supercharged, fuel injected.) In 1984 the 4A-ELU was introduced with improved helical ports with swirl control valves, programmed sequential injection and improved ignition system which helped the system in the ultra-lean, high efficiency lineup. The ‘A’ family of engines have been used primarily in the Corolla, AE82, AE86, AE92, AE101 & AE111, but can be found in the first generation MR2, AW11 as well as some lesser known Toyota models (Engine options may vary depending on the vehicles point of sale.) The 4A-F and 4A-FE engines have replaced the 4A-C in Corollas since 1988. In 1990 the A block deck height was lengthen, the crankcase slightly enlarged and a special oil pan extension was add to increase the displace of the A family to its largest, 1.8 liters. Its designation was the 7A.

1 comment:

Nikki Benz said...

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