SIngle player or multiplayer on my forge server I cant craft any engine parts. Using simple parts pack and the yeOld stuff. Can't make pistons or fuel cans. Very Confused. 1.12.2

It seems the crafting recipes weren't being created correctly, this should be fixed in the next version of the mod.

Until a new version is released, you can see the working but incorrect crafting recipes using a mod like "Not Enough Items".