Hi mate, it sounds as if you have found the source of you noise, skirt collapse, I’ve not managed to do that in any of my cvh blowups! …. but I did do some thing similar to 1700 cc Kent engine I had in an XR2 some years ago when the water pump pulley broke off of the end of the water pump at high speed on the motor way , the engine suddenly locked up due to over heating! …..,the result was a distorted piston in number 4 , when the engine was running it mate a very strange sound like some one taping a spoon agents a coffee cup?
So hopefully it will not be to long before you are back on the road

Cheers.

Steve.