4G54 Engine Torque Specs

by JoAnn Joubert
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The 4G54, or G54B, engine is also known as the Mitsubishi Astron engine. Production on this engine began in 1972. With a chain-driven single overhead camshaft, or SOHC, and eight valves, this engine provides plenty of torque for vehicles. Some features of this engine include heads with additional jet valves to improve emissions and a Hitachi two-barrel carburetor with a vacuum-operated progressive secondary in addition to hemispherical cylinder heads.

Basic Torque & Horsepower Specs

The 4G54 engine displaces 2.6 liters, or 2555 cc, with a bore and stroke of 91.1 and 98.0 mm, respectively. It was designed for longitudinal use in both rear- and all-wheel-drive vehicles, and with a multi-point fuel injection system, the 4G54 engine produced between 131 and 138 horsepower at 4,750 rpm. This resulted in a torque of 156 ft.-lb. at 3,750 rpm and 162 ft.-lb. at 4,000 rpm. The compression ratio is 9.2 to 1. The carburetor version of the same engine offers 114 horsepower at 5,000 rpm and 146 ft.-lb. of torque at 3,000 rpm. The compression ratio is 8.8 to 1 for the carburetor version.

Bolt Torque Values

While performing engine maintenance, it is essential to know the required torque values for the caps, nuts and bolts in order to ensure proper performance of your vehicle. Using a torque wrench, you can be sure you tighten these mechanical parts to the accurate torque value. For the main bridge caps, you will need between 54 and 61 ft.-lb. of torque, while the rod bridge caps require between 33 and 35 ft.-lb. The cylinder head bolts require between 65 and 72 ft.-lb., while the cam sprocket bolts require between 36 and 42 ft.-lb. The crank pulley bolt needs between 80 and 94 ft.-lb. of torque, and the flywheel bolt needs between 94 and 101 ft.-lb. The flywheel housing does not require any torque value during assembly or disassembly. The manifold nut and bolt require between 10 and 14 ft.-lb of torque. The oil pan bolt needs between 4.3 and 5.8 ft.-lb. The oil pan drain plug will need between 43 and 57 ft.-lb. of torque, and the oil pump bolt will need between 5.8 and 7.2 ft.-lb. of torque. The rocker arm nut requires of range of 3.6 to 5.1 ft.-lb., and the spark plug will need 18 to 21 ft.-lb. of torque.

Other Torque Specifications

The axle spindle nut requires 167 ft.-lb. of torque, while the axle flange bolt will need between 36 and 43 ft.-lb. The brake caliper bolt will need between 58 and 72 ft.-lb., while the companion flange-to-drive axle shaft nut requires between 116 and 159 ft.-lb. of torque. The hub cover bolt will need between 13 and 25 ft.-lb., the stabilizer bar bolt requires 45 ft.-lb., and the strut nut needs between 43 and 51 ft.-lb.

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