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.

Optional new technology- Refined Engine Units. Engines can alternatively be crafted with Light Oil.

There are multiple options in the startup settings off by default:
Refined engine units - Technology with an alternative recipe to craft engines using light oil instead of crude. (With space age it becomes available after coal liquefaction 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.

My other mod (optional) - Chemical Science Uses Petroleum https://mods.factorio.com/mod/chemical-science-uses-oil changes the tech tree to not require engines for Chemical Science as engines are removed from that recipe