The Mitsubishi Astron or 4G5/4D5 engine, is a series of straight-four internal combustion engines first built by Mitsubishi Motors in 1972. Engine displacement ranged from 1.8 to 2.6 litres, making it one of the largest four-cylinder engines of its time.
Mitsubishi G54B engine
Turbocharged and intercooled 4D56 engine in a 1991 Mitsubishi Pajero
Balance shafts are used in piston engines to reduce vibration by cancelling out unbalanced dynamic forces. The counter balance shafts have eccentric weights and rotate in opposite direction to each other, which generates a net vertical force.
Balance shaft in Ford Taunus V4 engine.
Lanchester's vertical force balancer. The eccentric masses are labelled "C" and "D".
Valve timing gears on a Ford Taunus V4 engine. The balance shaft runs off the small gear on the left (the large gear is for the camshaft, causing it to rotate at half the speed of the crankshaft).