Ever wondered why engines could run dry without seizing up? Want just a little bit more realism? This mod might just be for you.

This mod adds oil (crude) to the engine recipe in the early game. It also tweaks the technology tree to accommodate the new recipe changes by moving engines (and pumps, which require engines) behind oil gathering.

This change will make cars and trains slightly slower to unlock and ever so slightly harder to craft in the early game until you launch a rocket and craft Space Science, when a new technology- Refined Engine Units is unlocked and you can alternatively craft Engines with Light Oil or Lubrant (it's your choice)

There are multiple options in the startup settings:
Refined engine units (ON by default) - New technology with alternative recipes to craft engines. (With space age it becomes available after Space Sceince Pack or Base Game after advanced oil processing. This is to make engines easier to craft on other planets without crude oil as a resource.)
Expensive mode - which triples the requirements of steel and iron gears to 3 from 1
Add Iron Sticks - recipe also requires 2 iron sticks (a cam shaft and crank shaft)

Mod based on the idea of Engine Units Need Lube by vertani, which I liked, but found it difficult to integrate into a game easily as engines were too far down the tech tree.

See my other mods:

(Optional) - Chemical Science Uses Petroleum https://mods.factorio.com/mod/chemical-science-uses-oil - Chemical Science uses a selection of Crude Oil or Petroleum Gas instead of Engine Units, can be adjusted in the mods settings
Electric Engine Units are Motors https://mods.factorio.com/mod/electric-engines-are-motors/metrics - Changes the name of Electric Engine Units to motors, optionally changing the recipe to be more "motor inspired"

This has been created with AI, but I am responsible for the prompting (I'm new to code so I am learning)