My Astra is porly at the moment, after driving hard through the gears i got to the latter end of 5th and the turbo felt to just turn off, i tried a little in 6th and she didn't want to work, I pulled over and the engine was sounding fine, but then as I set off it was driving like on 3 cylinders and smoking bad and making terrible noises,
I decided to drive home anyway cos I couldn't be bothered waiting for the AA.
I whipped the plugs out and there are signs of damage on one of them, the piston top also looks like it has got the same marks on it, this is the one I call piston number1 at the dizzy end.
Piston 2 looks like it may have the slightest of marks and the last two look fine.
All the other spark plugs are perfect.
I am under the impression its one of 3 things,
2, something has broken off the turbo and been swept in, the air filter itself is unmarked.
3, a valve may have burnt out.
I checked the timing on the belt and it is still perfect.
Any ideas what detonation looks like and could it happen to the plug as well as the piston.
It looks like very small marks on the piston as though you have pushed a fork onto the surface and dented it slightly, nothing really major from what I can see through the spark plug gap.
The head will be coming off tomorrow if I manage to compression test it first.
I hope the pics work as i'm using a new uploader