Mitsubishi 4G18: Everything You Need To Know

Since the rise of the inline-fours, Mitsubishi continues to develop its arsenal by releasing multiple machines that can compete with the worldwide demand of such a vast automotive arena. This necessity led them to produce the Astron, Sirius, Saturn, and Orion Family series, also known as 4G1 engines.

And with that, we will take a more profound contrast on the 4G18 engine of the Orion family. Its engine design, power, applications, reliability, issues, tuning potential, aftermarket support, and many more.

What are Mitsubishi 4G18 Engines?

The Mitsubishi 4G18 is a notable member of the Mitsubishi Orion family or colloquially known as the 4G1 series of engines. It is considered as one of the oldest engines on the same engine family together with the 4G11, 4G12, 4G13, 4G15, 4G16, 4G17, and 4G19.

The 4G18 was produced in 1998, and Mitsubishi halted the production in 2012. But sill, many enthusiasts use this engine for their builds as this can be a good platform for that kind of upgrade.

In addition to that, Mitsubishi 4G18 is a water-cooled, inline-four with four valves per cylinder gasoline engine. With a displacement of 1.6 Liters (1584 cc) making it the largest engine displacement on the Orion series of machines.

It features a cast-iron cylinder block with aluminum heads and is integrated with the plug-top coil or COP (Coil-on plug) ignition system where the firing of two cylinders rely on one coil only, one of which is through a spark plug.

Along with that, it has a pentroof type combustion chamber and uses a new tightening method by use of bolts tightened in the plastic area.

However, in 2010, the Mitsubishi Motor Company started producing the next generation of 4G1s, which was named as Mitsubishi 4A92.

Engine Specifications and Design:

• Production Run: 1998 – 2012
• Cylinder Block Material: Cast-iron
• Cylinder Head Material: Aluminum
• Configuration: Inline-4
• Bore: 76 mm
• Stroke: 87.3 mm
• Valvetrain: SOHC with four valves per cylinder
• Displacement: 1.6 L (1584 cc)
• Compression Ratio: 9.5
• Weight: 254 lbs.
• Max HP: 109 HP
• Max Torque: 111 lb-ft

Mitsubishi 4G18 shares most of its engine architecture with the 4G15 and 4G13 engines but with a larger displacement. 4G18 is available on both the 16-valve carburetor and 16-valve multi-point injection system.

The engine’s cylinder block is made from cast iron with a deck height of 220 mm, 48 mm crankshaft diameter journal, 87.3 mm stroke, and a 76 mm cylinder bore, which has a noticeable dimension increase from the 4G15’s to buff the displacement to 1.6 Liters.

This engine was rated at 109 HP and 111 lb-ft of torque on European specifications and the maximum level.

The cylinder block is covered with a belt-driven single overhead camshaft 16-valve head with hydraulic tappets, so valve adjustment is unnecessary. And like other Mitsubishi Orion engines, it does not have the variable valve timing technology or MIVEC that allows the cam profile to adapt to specific driving conditions.

Applications of the 4G18 Engine:

• Mitsubishi Colt Plus (Taiwan Market)
• Mitsubishi Kuda
• Mitsubishi Lancer
• Mitsubishi Space Star
• 2010 – 2011 Foton Midi
• Hafei Saima
• Proton Waja
• Zotye 2008 / Hunter / Nomad / T200, 2007 – 2009 106 HP
• 2005 – 2010 BYD F3
• Hafei Saibao
• Foton Midi
• MPM Motors PS160
• Brilliance BS2
• Brilliance BS4
• Landwind X6
• Zotye T600
• Zotye T700
• Mitsubishi Lancer (China Market)
• Soueast Lioncel
• Haima Haifuxzing
• 2013 – 2014 Tagaz Aquila
• 2009 – 2013 Emgrand EC7

Engine Tuning, Upgrades, and Modifications

The Mitsubishi 4G18 engine is an incredible engine to tune with tuning mods like turbocharging, remap, and camshaft upgrades which can definitely heighten your engine performance as well as your driving experience.

One of the optimum ways to upgrade the engine, not only for 4G18 but also for the others, is replacing the camshaft; you have options such as fast and motorsport. There are three stages to accomplish in a typical engine upgrade, depending on the power upgrade of your choice.

But the first stage includes sports exhaust manifold, drilled and smoothed airbox, fast road cams, panel air filters, intake headers, and ECU remapping.

Stage two follows with a sports catalyst and performance exhaust, induction kit, fast road camshaft, and pump upgrades.

To proceed, you have two different ways to upgrade or make your engine faster than its stock power specifications apart from what we’ve mentioned above. And the most common builds are the naturally aspirated and forced induction.

For some, a naturally aspirated build is considered a waste of money since some of those who tried only resulted in a louder exhaust and a little bit of power boost, but you can try it.

You can start by installing a 60 mm throttle body, aftermarket air filter, 2-inch exhaust system, 4-2-1 header, and tune the ECU. These performance mod upgrades can add at least 15 to 20 HP.

However, if you still have money to spend, you can install an additional performance intake manifold, ITB, aftermarket cams, high compression pistons, adjustable cam gears, do some head porting and polishing; install a lighter flywheel and new spark plugs. Configure all these and gain some 5 to 15 HP.

And the other method is the forced induction. First, you need to find a turbo kit appropriate for your 4G18 engine and buy a turbo manifold, and some recommend the TF035 turbocharger.

Next is to buy a new oil feed line and oil drain line and put it all on the stock internals. You will also need a turbo piping kit, intercooler, 4G64 275 cc (or more) fuel injectors, a 2.5-inch exhaust system, a Walbro 255 lph fuel pump, Wideband O2 sensor, and a Greddy e-manage ECU.

The stock internals of the 4G18 is pretty weak, but it can survive a pressure up to 7 psi, and you can drive a little bit in this mode. But still, it is always best to consider the longevity and reliability of the engine.

So with that, we need to replace the stock pistons and connecting rod with forged ones. It would be best to buy forged low compression pistons, ARP head studs, H-beam rods, and an MLS head gasket.

It is also recommended to install oil jets for piston cooling to regulate the temperature through the cylinder. Add in some Mishimoto radiator, an oil cooler, a big intercooler, 630 cc fuel injectors, fuel rail, fuel pressure regulator, and a blow-off valve.

To gain more horses, you will need a large TD05 turbocharger, the one they use on EVOs or another with a similar size. With these performance parts, you can get up to 350 HP. If you are still not satisfied, you need to buy an aftermarket camshaft since the stock crankshaft does not have resistance to high power.

It is better to use a DOHC 16-valve cylinder head for the turbo to improve the engine efficiency.

Problems Surrounding 4G18 Engines

In a decade-old type of engine like the Mitsubishi 4G18, the risk of having issues is exceptionally high, and that is a simple fact due to its age, mileage, and years of service. Even though we wanted to preserve their peak condition, many factors won’t allow us.

So, with that, we created a list of some problems that might arise on the Mitsubishi 4G18 engine as a precautionary guide for you.

Let’s start by stating that the 4G18 shares most of its problems with other 4G1 engines, such as the 4G13 and 4G15.

And their common denominator is high oil consumption. High oil consumption translates to poor oil distribution, leading to a myriad of engine problems such as overheating and eventual engine failure.

This is prevalent among older engines but sometimes when you pass the 120,00-mile mark. This happens when you have left unnoticed leaks, some loose components inside, or just the normal wear and tear of the engine.

Replacing or tightening the necessary parts is needed or, much better, an engine overhaul.

The next issue is the engine won’t start. Engines that are situated or left in colder regions are the common casualty. 4G18s have not much resistance on frost, though all engines do.

The reason might be in the fuel pump, or if the fuel pump is good, check the spark plugs because that might be the problem.

There are also reports that some 4G18s experience rough idling. This issue can be caused by two factors, such as inconsistent fuel combustion inside the chamber and a worn-out throttle body or its case.

If the latter causes the problem, replace the spark plugs and spark plugs wire; if the latter, you just need to replace them, and you are good to go.

If the issue mentioned above is not addressed quickly, that is the rough idling; it might cause unnecessary vibrations resulting in engine mount displacements. This problem is all too common across the 4G1 engines.

So increasing the idle can solve this.

Another standard maintenance item is the timing belt. Make sure that the timing belts are replaced at around 60,000 miles to prevent valve bending.

To add to the mentioned above, regular maintenance and habitual checking go a long way for the engine. Use a good quality engine, and don’t forget to take note of the things you need to replace immediately.

Summary

The Mitsubishi 4G18 engine holds the largest displacement of the 4G1 engines. With a sturdy engine block integrated with a new ignition system as well as a new tightening bolt method.

It became more fuel-efficient, has an improved cooling system, and more power. It is also a good engine platform for tuning, provided with lots of aftermarket parts available for 4G18.

Though it has some issues and questionable faults, this engine has many potentials to show even at an older age. With the proper maintenance and regular inspection, the machine can surpass the 170,000-mile mark.

I hope that this simple guide and discussion helped you understand the engine design, power, applications, issues, tuning potential, aftermarket support, reliability, and overall impact on the industry and community.