weblogic connection timeout error

i am facing an issue that the server give a connection timeout after 60 sec for any request more than that number . i tried to increase the TCP INTERVAL TIMEOUT from the default 60000 ms to more higher number.
the server seems to work fine and didn't give me the massage of the timeout but the strange thing is that if i return the old setting 60000 the server never timeout like before.
i am running sun solaries 10 , weblogic 8.1
i need help please