240 degrees a three cylinder fires one.
180 degrees a four cylinder fires one.
every engine is designed to counter resonance and balance. Unless your a fan of vtec , inline fours and good vibrations (some peoples brains don't know what reality goes missing anyway...)
here is how to do it:
all you have to do is twist the crank with your bare hands to even it up a bit for when you want to switch to 3 cylinders.