Isometric games and Z Order

How to do I change the Z Order of an object at runtime to a certain value?

I am trying to make an Isometric game and one of the tricks for making the graphics show up in the correct order is to use something set their Z order to -1*(Y position), something like this:

Event: always

action: Set Z = -1*Y

I tried Z height but it actually scales the object.

Thanks in advance!

Add all your objects to a family.

Then add the following event:

For Each Family sorted by Family.Y -> Send to front

I made a test for a isometric games

here a link to my http://www.scirra.com/forum/viewtopic.php?f=16&t=5357#p49572

you sort by Y first then by the Z.