Mitsubishi 4G63: Engine's Legendary Performance Explained

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The Mitsubishi 4G63 engine has powered a number of vehicles for over four decades and is still in production today. What makes it so unique?

The Mitsubishi 4G63 is a 2.0L four-cylinder engine in the Sirius engine family that was produced beginning in 1980. The engine came in SOHC and DOHC configurations both as a naturally aspirated and a turbocharged unit. The 4G63 continues to be produced for vehicles today for Chinese markets.

When the Japanese automakers sought to outdo each other in building performance engines in the late 70s, Mitsubishi made a statement with its 4G6 family of engines. The 4G6 (also known as Sirius) was the popular power plant for many of their vehicles, including the Lancer, Conquest, Eclipse, and Mitsubishi Galant. Before long, both Hyundai, Plymouth, Eagle, and Dodge were using the motor because it was just that good. As the years progressed, the 4G63 gained fame as a reliable, sturdy motor, and by the time its variant won four consecutive world championships in the nineties, it was well on its way to being one of the most legendary performance engines ever made. Even though Mitsubishi stopped making the engine for the American market in 2007, the engine continues to be produced today for the Chinese market. Let’s look closer at the 4G63 engine to learn more about it.

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What Are The Features Of The 4G63?

The 4G63 is a variant of the Sirius engine family that was produced beginning with the 1980 Mitsubishi Lancer. The 2.0L engine is an inline four-cylinder with a closed deck design featuring a cast iron cylinder block and aluminum cylinder heads. The motor featured a timing belt rather than a chain to power the forged steel crankshaft. The engine was developed with both six and seven-bolt mains.

The engine was offered in three basic configurations. A single overhead cam (SOHC) naturally aspirated engine with two valves per cylinder. Later, Mitsubishi launched a single overhead cam turbocharged engine, and a double overhead cam (DOHC) in a turbocharged form. Later versions employed a variable valve timing system, which they labeled MIVEC. Most restorers/tuners tend to seek out the DOHC version that Mitsubishi built during the nineties.

The engine’s block is about as bulletproof as an engine can get, and with a standard bore of 3.35 inches (85 mm) and a stroke of 3.46 inches (88 mm), the basic 4G63 engine has plenty of low end torque for quick starts, and is capable of handling significant power boosts, which is one reason the 4G63 is so beloved by car enthusiasts everywhere.

The 4G63 also features a wasted spark ignition, with coils centered of the extended reach spark plugs in cylinder one and two. (Cylinder one has the coil with a plug lead extending to cylinder 4. The coil over cylinder two has a plug lead to cylinder three).

There no timing chain on the 4G63, both the dual camshafts and the crankshaft are rotated with a timing belt. The 4G63 engines built in 1990 - ‘92 use a six bolt for the crankshaft, while later versions (late 1992 - 2002) use a seven bolt system.

The Evolution Of The 4G63 Engine

The engines produced a variety of power outputs during their years. One of the first versions of the SOHC 4G63 was naturally aspirated and produced 102 hp and 116 lb-ft of torque and was used in the Mitsubishi Gallant for a number of years until 1993. Later turbocharged versions had higher outputs, including the 2003 Lancer Evolution where the power ratings had increased to 271 hp and 273 lb-ft of torque. (This version was a 16 valve, intercooled and turbo-charged powerplant).

American buyers were introduced in a significant way to the motor when Mitsubishi and Chrysler formed a partnership for the 1989 model year. The new venture would create “Diamond Star Motors” and would feature the Plymouth Laser, Eagle Talon and Mitsubishi Eclipse all to be built at a US plant in Normal, Illinois. Even though Chrysler had been rebranding Mitsubishi models as Chrysler, Dodge and Plymouth compacts since the seventies, Mitsubishi longed to establish itself as a separate brand in the ever-widening US market. Since regulations at the time limited the number of vehicles that could be imported from abroad, Mitsubishi saw this as a way of getting a foothold in the US.

The 4G63 is best known for its use in nine generations of the Mitsubishi Lancer Evolution from 1992 - 2007. During this time, the Lancer Evo III won four consecutive championships with a turbocharged variant. In addition, the 4G63 has an extensive record on the FIA circuit, with the Lancer Evo dominating the events from 1995 - 2001, and when Proton beat them, it was still a 4G63 engine powering the winner. Mitsubishi cars had a wealth of experience in the rally events, but the wins cemented the 4G63’s legacy.

The 4G63 has also been used extensively in drag racing applications. Many Diamond Star Motor (DSM) cars have recorded extremely fast times. Iconic names like David Busuhur, Sean Glazar, and Tony & Bob Niemczyk were just a few of the drivers who were modifying their 4G63 racers to speed down the track. Today, the mighty 4G63 continues to impress with times rarely seen from a four-cylinder engine.

Mitsubishi replaced the 4G63 in 2007 in the Lancer Evolution IX, when it began using the 4B11 family of engines. However, the rising Chinese market offered unique opportunities for development, and Mitsubishi began a joint venture with several Chinese automakers to produce the 4G63 for use in many of their models. The company continues to make the 4G63 variant for Chinese automakers even today.

The Mitsubishi 4G63 Engine Specs

Mitsubishi 4G63 Engine Specification
Production 1980 - Present
Cylinders 4
Layout SOHC (2 valves) SOHC (4 valves) DOHC (4 valves)
Displacement 2.0L - (1,997 cc)
Compression Ratio 9.0, 9.8, 10.0, 10.5
Aspiration Naturally Aspirated and Turbocharged
Valves 8 and 16 valve
Fuel System Electronic Multi-port Fuel Injection
Horsepower 92 - 271
Torque 167 - 273 lb-ft
Engine Block Cast Iron
Cylinder Head Aluminum
Intake and Exhaust Valves 34 mm (4G63T)
Bore Size 3.35 inches (85 mm)
Stroke Size 3.46 inches (88 mm)
Firing Order 1-4-3-2

What Are Some Of The Issues With The 4G63?

As good as the 4G63 engine has been over the last almost half a century, there are some issues that tuners should be aware of.

Six Bolt Or Seven Bolt Mains

The main From 1990 - ‘92, Lancer Evolutions used stronger connecting rods and six bolts to attach the flywheel to the crankshaft. When Mitsubishi switched from late ‘92 - ‘06 to seven bolt mains, they decided to use lighter rods (in an attempt to lighten the massive weight of a cast iron block) and seven bolts. Unfortunately, the seven-bolt engines are less accepting of boosts due to the weaker connecting rods.

In addition, the seven-bolt engines can have weaker thrust bearings on the crankshaft. This issue can cause failure of the bottom end of the engine.

Secondary Timing Belt Failure

The 4G63 has balance shafts that are driven by a secondary timing belt, which has a tendency to fail. Eliminating the weak balancers and these timing belts is a common fix for this issue, but care should be taken when performing the operation. For more info, see how to remove the balance shaft at High-Performance Academy. (Removing the balance shaft will increase the engine's vibration, but most owners who are looking for more horsepower think it’s a reasonable tradeoff).

Small Throttle Body (NA)

Naturally aspirated 4G63 have smaller throttle bodies that do not handle the excessive flow of forced induction. Installing a larger throttle body is a relatively easy fix, and there are plenty of purveyors who can provide aftermarket support.

Hydraulic Lifters

Some 4G63 engines can have hydraulic lifters that wear out. The most common symptom of this issue is a “ticking” that might come from the engine. If you detect this sound, the hydraulic lifters may need to be replaced. (Some owners have had success by switching to a high quality engine oil, which can often smooth out the tapping sounds).