Mitsubishi 4G69 engine

1. Specifications
2. Overview, problems
3. Performance tuning

Specs

Mitsubishi 4G69 engine reliability, problems and repair

The newest 4G69 engine from the Sirius family was launched in 2003 and the first cars with it were Mitsubishi Grandis and Mitsubishi Outlander. This engine is a successor to the 4G64 and has some differences.
Let’s look at the main differences between the 4G64 and the 4G69.
This engine uses a cylinder block with a reduced deck height of 229 mm, like the 4G63. A lightweight crankshaft with a piston stroke of 100 mm is installed inside it. They increased the cylinder bore from 86.5 mm to 87 mm, installed new lightweight pistons with a compression height of 28 mm. Also, 151 mm connecting rods are used here and they are also new and lightweight.
The crankshaft weighs is 14.9 kg, the pistons weigh is 278 g, and the connecting rods weigh is 530 g.
Balance shafts are still used in the cylinder block.

A new SOHC 16-valve head with variable valve timing and valve lift system MIVEC on the intake side has been created for this engine. This system switches between the modes at 3,500 rpm. The size of inlet valves is 34 mm, of outlet valves — 30.5 mm, and valve stem diameter is 6 mm. You won’t find hydraulic lifters here, so you have to adjust valves every 30,000 miles (50,000 km). Valve clearances for a cold engine are the following: intake — 0.1mm, exhaust — 0.2mm. Valve clearance for a hot engine: intake — 0.2 mm, exhaust — 0.3 mm.
You can also come across a 4G69 GDI with a direct injection system. Here the increased compression ratio is increased to 11.5:1; it has a modified head, a new intake manifold, and a modified header. The size of the throttle body is 55 mm.
The 4G69 engine uses a timing belt; it has been modified and is narrower than in the 4G64. It should be replaced every 60,000 miles (90,000 km).

Along with this 4G69, the Sirius family includes the following engines: 4G61, 4G62, 4G63, 4G63 turbo, 4G64, 4G67, 4G69, 4D65, and 4D68.
Mitsubishi has replaced this engine with the more modern 4B12, but you can still find a new car with a 4G69, and it will probably be a Chinese car.

Mitsubishi 4G69 engine modifications and differences

1. Idle problems. Check whether the throttle body is clean; also check the idle control valve, fuel injectors, and the ECT sensor.
Usually, the reason is here.
2. Engine noise. This usually occurs after replacing the timing belt. If this is the case, you may have installed the balance shafts incorrectly, or you may have overtightened the balance shaft belt. Maybe, the crank gear and the balance shaft belt are of poor quality. If no replacement has been made and the noise started, there may be many reasons. The valves may be unadjusted, or maybe a connecting rod bearing is noisy and the engine is about to kick off. This should be determined personally by a specialist.
3. No spark. The problems are usually in the camshaft position sensor or the crankshaft position sensor, or the ignition coils. Check these.
Also, don’t use poor quality engine oil; it may cause problems with the bearings of balance shafts and their jamming.
The use of a balance shaft delete kit seems a good option.
Also, the 4G69 loves high-quality gasoline more than the 4G64. Poor quality gasoline can kill your catalytic converter.
Despite everything, to the question, whether the 4G69 a good engine, I will say that this is a very reliable and durable engine. If it is serviced regularly, its lifespan will be more than 250,000 miles (400,000 km).

Engine number location

Stand facing the engine, the exhaust manifold is right in front of you. The number is under it, on the left.

Mitsubishi 4G69 engine tuning

N/A build

This engine has a good head and it can show a good result. You can install a cold air intake, a 60 mm throttle body, a more aggressive camshaft, a 4-1 header, and a 2.5-inch exhaust system, and tune the ECU. These performance parts will give you +20 – 25 HP.
You can go further, but this engine does not like more than 7,000 rpm.
This head has good potential and if you port and polish it, install an oversized intake and exhaust valves, the results will be even better. You will also need forged rods and pistons, an aftermarket intake manifold, a lightweight flywheel, and more. All this is very expensive, and the main problem is low revs, therefore, using a racing camshaft will be difficult.
I think it would be smarter to consider the ways described below.

Turbo

To start with, your bottom-end is pretty weak and should be strengthened. 4G69 stock internals can withstand 300+ HP, but not long. Theoretically, you can buy a turbo kit or a supercharger kit, and install it on your stock block.
However, I’m talking about reliability here, so buy the following aftermarket parts:
– oil jets
– ACL bearings
– H-beam rods
– ARP rod bolts
– forged pistons (CR = 8.5 – 9)
– ARP head studs
– an MLS head gasket
Now you have forged internals, let’s move on.
You can leave your SOHC head or use the variant of the 4G69 block with a 4G63 head. The latter method looks great, and the results will be very impressive.
Let’s see what it takes to build a 4G69 with an Evo 9 head (can be an older one):
– a 4G63T head
– an Evo intake system
– an Evo ignition system
– an Evo fuel system
– an Evo turbo
– an Evo turbo manifold
– a 3″ exhaust system without narrowings
– an Evo ECU + wiring
As a result of such DOHC conversion, you will get a complete Evolution 2.4 engine, but with a 4G69 block. Tune the ECU, and you will have about 400 HP at the crankshaft.
You can make this motor love high revs using a 94 mm crankshaft + 156 mm rods + forged pistons (CH = 26 mm). This destroker will reduce the displacement to 2.23 l, but you can get 8,000 rpm.
You can go further and use an Evo crank, then the working volume will be 2.1 liters, but you will be able to reach 9,000 rpm.
The height of the Evo and your 4G69 blocks is the same, which means you can choose other stroker kits. I wrote more about 4G63 performance tuning HERE.