BUKH DV20 refubished cylinder head refitted . Part 2

BUKH DV20 cylinder head overhaul. 1973 model bukh with bosch dynastart for starting and charging . Head refaced, valve seats recut, valves refaced and lapped in, valve guides ok, cleaned out waterways, although not too bad.
I think the original cause of the Bukh DV 20 head gasket failing was due to a major overheat when the thermostat (old type)failed in the closed position which still allows water to bypass to the exhaust so looks as if the Bukh engine is still being cooled. The smell of burning paint was the first I knew of a problem. I shut down and it took over 2 hrs. to cool down enough to be able to touch. I removed the thermostat and restarted to get back to my berth. I then repalced the thermostat.
The Bukh engine ran fine for 2 years. Then 2 months ago I was changing some cooling hoses(will be changing to rubber). When the hose was off I turned the engine over and found gas pressure from the failed gasket was forcing the water out of the open pipework. On removing the rocker cover Ifound traces of emulsified oil on the underside and with no leaks from the water pump, more or less confirmed the head gasket.
This is the second video of the Bukh engine repairs and the fitting of a new head gasket.