Factorio Forums

is there any way to turn off my oil cracking when i get above a certain amount of an oil type?

You can try using pumps and stuff so that a tank can't empty, because the cracking wills top if the plant can't drain.
There might be other ways but I just manually tweak the numbers of active cracking plants.
If there's no system now, there will be one day! Oil is still a relatively new feature.

is there an easy way to shut them off? i am just removing the oil line in to stop them

I take down the power lines feeding them. I have them positioned so that I just need to plonk one pole down to power 1 or 2, and then another for each extra 2.

short answer: no
long answer: http://i.imgur.com/murrRAw.png
the yellow oil is mostly useless, red can be used for lube = blue speed/ red motors, what you need the most of is gas.
So i just build some to change the yellow oil into gas.

you can control the plastic/sulfur. sure not perfect way but better then nothing