I have a 1.416v Astra, Recently been having problems with the tappets, I've since flushed the engine and changed the oil aswell as adding whyns lifer treatmant. It was driving great for around 3 days then alll of a suddan as driving i lost power and it developed a nasty knocking noise as. It's now missfiring on number 4 and knocking. The knocking sounds llike its coming from the top end so i took the rocker cover off as i was told one of the lifers may have become jammed but on insepction all 16 lifters seem to be moving fine. Anyone have any ideas what else it could be? big ends? cam belt jumped a tooth? also the engine managment light hasnt come on so i'm ruling out injectors or coil?
Any help would be most welcome.