I set out to change the head, to the one which I robbed from the 820 Si donor vehicle I was given. The Job took 3 days! not through lack of mechanical knowledge, but sheer inexperience in working on this particular car ( I am a vauxhall man personally )
It was put back together, and wouldnt fire up! I tried everything-Changing the ECU's, Coil, Cap etc. I could smell fuel vapour from the exhaust, so it wasnt a fuel problem. The problem was eventually traced back to the crank angle sensor multiplug. At some stage in it's life, it must have suffered from water ingress, as the wires were badly corroded, and had broken off during disconnection, and were behing hidden by the rubber sheathing that covers the connections!
The connections were re made, and this time, it would "catch" but not run. This caused more aggro, in the form of drinking lots of beer, and generally not being nice to the cat , as it was now dark and I couldnt do any more. Besides, I had flattened the battery, and had no Jump Leads or charger!
The next morning, I had the bright idea of reversing the connections on the crank sensor, just to see if they were wrong. I turned the key, and the engine started to turn over, then began to die. Then, Bingo! she ran!
I let her warm up, and the tappets went silent-the only clicking noise to be heard was the injectors rattling away. I looked down in the "Cavern" in the head, where the spark plug tubes are, and could see water. Not to worry, I thought to myself, It has been raining, and I did leave the bonnet up when I ducked inside to avoid the downpour......
Wrong! The head is cracked! If I am not careful, it boils up if I leave it standing too long ticking over!
Which means, I am gonna have to replace the damaged valves, and replace the original head, which is fine.
The only thing I can assume, is that they cooked the engine on the Si when they were thrashing it about the field. I should have been suspicious when I saw the 2 terminals that connect to the radiator fan switch linked by a spade fuse!!
The head change will be done in the near future. Will keep you posted.