Well, after months of waiting due to weather and ill health, it's finally in!!
. I admit I cheated and had my local garage help with installation as I wasn't really fit enough to do it on my own and I don't have the facilities to do it at home anyway.
The new clutch lined up fine and the block and gearbox went together sweet. Connected everything, swapped over a few parts from the L20 engine and topped it up with oil.
We decided to crank it over before filling it with water to make sure everything was fine so made sure there was no possibility of a spark and turned it over without the spark plugs. All seemed well, no large bangs or rattles indicating something shearing or breaking. We compression tested each cylinder and there was good even compression across all so we connected all the ignition bits and turned it over again. It fired up after about 5 turns
All seemed good. Had good oil pressure and it ran smooth with no noises and no oil leaks. There wasn't even any need to tune the carbs but the ignition timing needed a tweak. Then the problems started.
Suddenly the rear carb started spurting fuel out of the overflow like a fountain. Took the float chamber lid off and reset the float level and checked the valve. Put it together - success.
We then decided to fill it with water. Fired it up. Again, good oil pressure and running nicely then I noticed the radiator draining rather rapidly.
I had already expelled all the air from the system and I also noticed the oil pressure dropping sharply. No water on the floor or spurting out of anywhere so we started doing the checks.
It was only when we checked the oil that we realised what the problem was due to the nice creamy texture on the dipstick and the oil filler cap. Immediate thoughts were head gasket but we sort of ruled that out as the compression was still at the same levels and also there was water in the oil but no oil in the water. Normally with a head gasket failure, it would mix in both. Also the failure would not be that quick and catastrophic so as to drain all the water in to the sump. The next thought was a failure in a bore lining but there was no trace of evidence when the spark plugs were removed and again there was no oil in the water.
Finally, I remembered that there was a small crack in the front timing chain cover. I didn't think it was anywhere near a water channel but on closer inspection it was closer to the water pump housing than I thought. I reckon that this has opened up and the water was pumping straight into the cavity around the timing chain and straight into the sump. This sort of makes sense as the level on the dipstick had doubled.
Luckily I have a spare timing cover and will shortly be getting some more gaskets from Mr F so that I can swap it. Hopefully that will cure it otherwise the Head will have to come off to change the gasket unless anyone thinks of another cause.
I'll keep you all posted.