AMC straight-4 engine

The AMC straight-4 is a 2.5 litre, 150 cubic inch inline four-cylinder engine that American Motors Corporation developed in-house and fitted to AMC, Jeep and Dodge vehicles from 1984 through 2002. AMC spent about three years on it, laying it out around the cylinder-bore spacing and the machine tools of its straight-6 so that existing tooling could be reused, and it took the place of the four-cylinder engines AMC had been buying from General Motors. The engine has five main bearings, eight overhead valves worked by hydraulic lifters and pushrods, and a bore and stroke of 3.875 by 3.1875 inches. It began with a one-barrel carburetor, moved to throttle-body fuel injection in 1986 and ended with multi-port injection, rated at 105 horsepower early on and 121 horsepower at the end. From 1997 it was marketed as the PowerTech I4, and the Beijing Jeep joint venture built it in China as the C498QA.