hello there i have just replaced a head gasket on a 1.8 sri vectra with the help of the haynes manual. once i put it all back together and tryed to start it it wont. it sounds like there is no spark. when i turn the igintion and try to start it for 20 seconds constant it seems to bellow out a load of smoke from the throttle body. theres plenty of petrol and full of oil and water. have adjusted the timing about three times now and have run out of ideas. the only thing that went wrong when i was taking it apart when i removed the inlet manifold from the head it arced across on the alternator and sparked a few time because i stupidly forgot to take the negative of the battery. ive checked all the fuses but werent sure about the relays. the car did over heat before the head gasket was done and it was gone between the 2 bores and a water hole. please help im stuck and out of ideas cheers paul