cast iron or pvc

treerat

got my bathroom tore down to the ground, and now I know what I have,

going in from the outside:
4 foot from the bathroom wall is a 4" pvc clean out on a 4" pvc y, somewhere in the next 2 foot it changes to 4" cast, then to a cast y for the tub drain, main cast 4" continues to a cast 4" y then lead pipe for the toilet.
then the main has another cast y plumed into a 4" cast vent stack outside the old wall, then the main steps down to 2" y to drain lavatory then at the end is 2 " to drain the kitchen sink into. kitchen sink is 4 foot away.

all of the cast y fittings are within 4 foot area.

can the 4" cast dry vent handle all these? seems like I am missing a vent somewhere?

and my main question, since it would be so easy to dig up the cast and replace it at this time (have to do foundation work too) should I replace the cast with pvc, or work with the cast. as I would really like to move the tub and toilet to different locations. ( the way it was the toilet sits right in line with the bathroom door, so if you are sitting in the living room and someone doesnt shut the door you see EVERYTHING!

so do I use expensive cast fittings or tear it all out and lay pvc?

Just Bill

PVC is easy to work with, inexpensive, but noisey. If in ground, noise is not an issue. Cast iron will last 100 yrs, if done right will not leak at joints, but the joint part is hard unless you use rubber fittings. Knowledge in making lead fitting joints is dwindling.