Replacing toilet..

[goofy gorilla]

Gonna replace my old toilet with a new one..I have the old cast iron soil pipe. Currently it's connected to wc with the attachments in pic...what would I need to connect new wc to soil pipe...? Also got a pipe from sink waste going into the wc connector..see pic..

 

[Hugh Jaleak]

what would I need to connect new wc to soil pipe...?

A lot of luck to start with I think. I'd be pretty confident the new WC pan will have an outlet lower than that existing one, cutting the cast back close to the wall might give you enough fall on the outlet pipe, but it already looks like your asking the proverbial to run uphill, and it only thanks to a decent flush that things are shifting already....

If that will work in terms of fall, (I'd check before removing existing pan), then you can easily get a Pan Connector with a Boss for the basin connection, just use an extension section to make up the gap to the soil pipe.

 

[goofy gorilla]

I've had that wc for ages never had any issues when flushing ...I was thinking of cutting the lip off the collar on the caste iron soil pipe...will make sure I check the new wc has a higher outlet like the present one..

 

[Hugh Jaleak]

I've had that wc for ages never had any issues when flushing ...

That might be your downfall, the existing is a 'Low Level' setup, probably A 9 litre flush and will do the job very well. New WC's are 6 litre flush, Close Coupled, and (as you may well find out), have a woeful flush performance compared with their predecessors. The 6 Litre flush was introduced as a Water Saving exercise, which has also proved woefully inadequate, as many people are now finding they have to flush at least twice, (so using minimum 12 litres of water instead of 9), just to clear the ruddy pan.

Then asking the contents to go uphill on their exit (as new Pans are Horizontal Outlet as standard, so outlet is higher than older P trap pans), just becomes too much....

 

[wundaboy]

That doesn't look like an easy job, as said above. Assuming that cast iron pipe is going out to an external stack, I think you're going to have to replace the pipe going out through the wall and change the level and angle in order to connect successfully to a modern toilet.