For an abridged version of the data provided here, see Energy Quick Reference.
Engines are at the core of any adventurer's journey toward automation in Minecraft, and as such it is essential that one understands how they work and how best to utilize each type of engine.
Redstone Engines provide the least amount of power of the three default engine types and are best suited for low energy needs such as powering wooden transport and liquid pipes. Multiple redstone engines can also be used as a cheaper long-term substitute for steam engines if combined with conductive pipes.
Steam engines are a sort of "go to" engine for moderate power needs. One steam engine is enough to power a Quarry with a small delay between each action (moving mining arm to position, mining, and descending all count as separate actions), although many adventurers elect for a small array of steam engines or to move up to the final tier of engine for maximum efficiency.
The combustion engine is the third and final tier of engine. It produces the most energy, but is also the most expensive engine to maintain as well as the most dangerous - a combustion engine with insufficient cooling can explode with disastrous results for your machinery and piping. One or two combustion engines are enough to power any BuildCraft device at maximum speed.
Energy Input, Storage, and OutputEdit
Each engine has its own characteristics that make it suitable for different tasks. These characteristics can be categorized as its energy production rate, maximum energy, and energy output.
Energy Production RateEdit
Each engine produces energy at a different rate according to its tier. The production rates are as follows:
1 MJ per second when blinking red
1 MJ per tick while burning something (20 MJ per second)
1, 3, or 6 MJ per tick according to fuel (20/60/120 MJ per second)
Redstone engines merely require a redstone signal to generate energy. Steam and combustion engines, however, require a compatible fuel source. Burn times for each type of fuel are listed below:
|Steam Engine Fuel Sources|
|Item||Burn time in ticks||Burn time in seconds|
|Wooden Items (Logs, Planks, Bookshelves, etc)||300||15|
|Coal and Charcoal||1600||80 (1 minute 20 seconds)|
|Bucket of Lava||20000||
1000 (~16.6 minutes)
|Combustion Engine Fuel Sources|
|Item||Energy per Tick||Burn time in ticks||Burn time in seconds|
|Lava||1||8000||400 (~6.6 minutes)|
|Oil||3||20000||1000 (~16.6 minutes)|
|Fuel||6||100000||5000 (~83.3 minutes)|
Of course a combustion engine can receive fuel sources via pipes, so the burn time is often less important than how much energy is generated per tick.
It is important to note that engines will generate power if supplied with redstone and a fuel source (if required), even if they are not hooked up to any devices or pipes. They will continue to accrue energy (and heat for combustion engines) at their standard rate, but will have nothing to output to. If left running, they will eventually acquire enough energy to explode. This is one of the few ways a redstone engine should explode. However, redstone engines are coded slightly different than other engines and currently do not explode from a self-generated energy overload. This allows them to continue gaining energy indefinitely as long as they are not being powered by any other engines.
Each engine has an internal buffer of energy that it can store. How much energy is stored determines the color of the engine. If you let certain engines gather too much energy, they can explode! As an engine gains energy, the color and piston speed change to reflect the amount. The color is purely a visual clue for the player to quickly check the status of his engines, while the piston speed affects the energy extraction rate. With less than 25% of its max capacity, an engine will remain blue. With less than 50% it will be green; 75% and below and the engine runs yellow. Below 100% an engine will run red. If an engine is allowed to exceed 100% of its energy storage, it will explode. Below are the max energy and stage thresholds (top number) as well as their corresponding piston speed (bottom number):
|Engine||Max Energy Storage||Blue||Green||Yellow||Red||Exploding|
|Redstone Engine||1000 units||<=250E||<=500E||<=750E||<=1000E||>1000E|
|Steam Engine||10000 units||<=2500E||<=5000E||<=7500E||<=10000E||>10000E|
|Combustion Engine||100000 units||<=25000H||<=50000H||<=75000H||<=100000H||>100000H|
Note that redstone and steam engines may only explode due to an excess of energy, while combustion engines will only explode due to an excess of heat. Heat is generated at the same rate that energy is in a combustion engine. For example, if 50 MJ were produced, 50 heat units would be produced as well. A combustion engine only begins to cool itself once it reaches a specific heat threshold, currently set at 49000 heat.
As well as creating energy at different rates, each engine outputs energy at different rates as well. The following table lists the maximum output rate and piston speed of each engine through the various energy stages:
|Engine||Max Output per Cycle (E)||Piston Speed|
The numbers provided indicate how quickly the piston moves per tick. When the piston reaches the end of the engine core (0.5 units), it will attempt to output energy to the object it is pointing at and will do so if it meets the prerequisites of that machine.
Given the different piston speeds, it is then possible to ascertain some typical running scenarios for each engine. In the table, Speed refers to the speed of the piston and TTE refers to the ticks to extract- the minimum number of ticks required before the piston reaches the end of the core and attempts to output energy.
As is evident, a steam engine running red can output energy every 8 ticks, the fastest possible cycle time. It is not possible to maintain this state for long, however, as the engine by itself can only generate 8 MJ in that time while more than that will be extracted by pipes or machines. It would be more feasible instead to opt for a combustion engine that will output at a slightly slower rate but can output 5x as much energy as a steam engine.
A redstone engine left to run long enough will always fluctuate between yellow and red stages. From blue stage to yellow, the redstone engine generates more energy per cycle than is expended. At the red stage the engine cannot keep up with the cycle rate and will quickly decrease back to yellow. It will continue to fluctuate between the two stages as long as it can output power to a device or pipe.
A steam engine by itself will normally operate at a blue stage. Given that it generates 1 MJ per tick, it takes 52 ticks to cycle, and the maximum output of the steam engine is 100 MJ; a steam engine connected to wooden conductive piping will output all the energy it generated since the last cycle.
A daisy chain is a common term for linking several devices in a row to one another. In this case, engines can be daisy chained to provide power to the next engine, which in turn can power another engine or a machine.
If done incorrectly, daisy chaining does not additively power the end machine as one would expect. Daisy chaining always accomplishes two tasks, however- heating up the lead engine quicker and maintaining that heat such that it may perform at optimal conditions. To chain engines effectively, at least one wooden conductive pipe and one other type of conductive pipe must be used to extract the power from the lead engine. If no pipes are used the chain effectively has the production rate it should, but the output of only one engine. This is due to each engine's maximum output rate as well as any machine's maximum input rate. To demonstrate this in game, chain a few engines together and attach the lead engine directly to a quarry. Now, power another quarry with just one of the same engine type. If both quarries are powered on at the same time, it is observed that the framing system for the quarry is built at exactly equal speeds for both setups. The only difference is that the chained engines will heat up faster, thus providing a boost to efficiency earlier on.
With conductive pipes, daisy chaining becomes a more viable option. Two daisy chained steam engines are almost as effective as two steam engines powering the conductive pipes separately. The benefit, however, is that only the first engine on the chain has to be fed fuel- it will then power the rest of the engines with a slight decrease in power per engine.
Limited testing has shown that daisy chaining redstone engines does not carry additional benefits. In fact, testing showed that no matter how many are chained together, they will all change states (from blue to green, etc) at precisely the same moment if they were all powered on at the same time.
As of 3.2.2, redstone engines can no longer be daisy-chained or hooked up to conductive pipes.