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The Mitsubishi 4G61 Powerplant


The Mitsubishi 4G61T is a 1.6 liter, four cylinder, turbocharged engine first seen in the Japanese market Galant. It is nearly identical to the 4G63T installed in the Mitsubishi Galant VR-4, Eclipse, and home market Starions.

It is a high-reving, short-stroke motor, and in the Mirage/Colt turbos produces 135 hp in stock form. Japanese market Mirages were intercooled, and produced 145 hp stock. The normally aspirated 4G61 fitted in the 90-91 Colt "GT" and the 92-94 Hyundai Elantra produced 105 hp. The redline on the US market 4G61 is 7000 rpm.

It differs from the Eclipse's 4G63T primarily in bore and stroke dimensions, and in the fact that due to the short stroke, it does without the power-robbing balance shafts. It is also equipped with a smaller, lighter flywheel. The 4G61T uses a Mitsubishi TD04 turbocharger, identical to that on the automatic transmissioned Eclipse, and the Misubishi 3000GT/GTO VR-4, though the 3KGT/GTO has two of 'em (lucky bastards).

The engine has no major reliability problems, and only requires normal maintenance to give 200,000 miles or more. The engine is equipped with hydraulic valve lash adjusters, which have been known to fail, and the timing belt needs replacement every 60,000 miles. The water pump should be replaced every other timing belt change, but only because if it goes, you have to pull the timing belt to get to it. You may as well replace it and save the headache. One thing to keep in mind is that the identical engine was fitted in the 92-94 Hyundai Elantra, so always check the parts prices with them. I have found Hyundai parts to be around 30% cheaper than the identical Mitsubishi parts.


Here are some vital stats of the 4G61T, as fitted to the 89 Mirage/Colt, with 4G63T specs for comparison:

Engine type

4G61T

4G63T

Bore (mm)

82.3

85

Stroke (mm)

75

88

Displacement (cc)

1595

1997

Compression Ratio

8.0

7.8

Firing Order

1-3-4-2

1-3-4-2

Valve timing

Intake Opens (BTDC)

21 degrees

21 degrees

Intake Closes (ABDC)

43 degrees

51 degrees

Exhaust Opens (BBDC)

48 degrees

55 degrees

Exhaust Closes (ATDC)

12 degrees

9 degrees

Valve Overlap

33 degrees

30 degrees

Intake Valve Duration

244 degrees

252 degrees

Exhaust Valve Duration

240 degrees

244 degrees


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