Forge version 1614 for 1.7.10 and only buildcraft loaded
In objects.cfg, I disable Redstone Engine, but the recipe still work and give a "unkown.name" item.
I put it on floor, then I want to remove it and game crash.

I am sure ONLY the Enginblock can curse this bug, other disable item can't be crafted.
I disable all 4 engines but engineblock recipes can be still found in NEI

Yeah disabling all engines currently doesn't disable the engine block itself, and so it doesn't disable the crafting recipe to make the engine. Which causes a game crash.

a simple check if the engine is enabled before registering the recipe should fix it then

it can't realy be crafted, it's only visible in NEI because the base item still exists

JEI replaces NEI on 1.8+, if the engineblock is dissabled it won't have a valid rendering so JEI will not show it

can be closed