The Engine is one of the basic craftable products in the Assembly Line games. While the blueprints and uses vary between AL1 and AL2, in both games it is generally not sold directly except possibly in the earliest stages of the game.
The primary usage for Engines in both games is as part of production chain to ultimately create AI Robots. Engines are used to craft Advanced Engines, which are in turn used as part of Electric Engines (and to a lesser extent Electric Generators by way of Generators), then Robot Bodies, and ultimately the AI Robot itself.
AL1 Engine Blueprint
Engines in Assembly Line 1[]
Engines are produced in the Crafter and are made from 2 Iron Gears and 1 Gold Gear. While they are not particularly valuable on their own, they constitute a significant portion of the raw materials used to produce AI Robots. In addition to Robot production, they are also used in the production of Washing Machines and Drills.
Engines in Assembly Line 2[]
The production chains and technology trees of AL2 are far more direct compared to AL1 which has numerous final products besides the AI Robot. Engines are only used as a component in the blueprint for Advanced Engines. Like all other tier 1 products, Engines are produced in the Crafter MK1. They are one of only 2 tier 1 blueprints that can be made from only one raw resource (the other being Batteries) in that they are made from 1 Iron Gear and 1 Raw Iron.