Catalytic Converter problems think it could be engine!

[wightman]

i have vauxhall corsa 1998 1.4 GLS. i was driving the other day and my catalytic converter faild i got a new 1 put on then that just done the same! (loud, back firing, loss of power) i went to take it to the garage today i got 1 mile driving it and there was smoke coming out of the engine! i had to keep stoppin and leavin it for a while just to get home! then i noticed there was oil coming out of the manifold/downpipe!! what could be causing all this? my timing belt got done at 95K and its now at 103k i now that the timing belt was out by 1 tooth on the belt! could that be it? can some1 please help me as i seriously don't know what to do thanks alan

[PRICER]

sounds as tho either your bores and pistons and rings are worn by the sounds of it mate with it chucking oil out. either that or your cylinder head valve guides are worn out. well thats my take on it anyway.

[wightman]

tbh i am not sure if its oil or whatever! i just want to now what is causin the problem with the catalytic (as in why has it faild the new 1?) can some1 please helpme out