could it be little end play, causing the piston to kiss the head,
compression doest look to bad to be honest,
between cylinder 1 and 2 its slightly lower in comparison to 3 and 4, could it be a possible blown head between 1 and 2 on the cylinders, not the water jacket,
in thinking whilst 1 is on its exhaust stroke, 2 is on its compression stroke, its losing compression between cylinders, so knocking/tapping due to pre or post ignition, ( thats if its cyl 1,3,4,2
compression doest look to bad to be honest,
between cylinder 1 and 2 its slightly lower in comparison to 3 and 4, could it be a possible blown head between 1 and 2 on the cylinders, not the water jacket,
in thinking whilst 1 is on its exhaust stroke, 2 is on its compression stroke, its losing compression between cylinders, so knocking/tapping due to pre or post ignition, ( thats if its cyl 1,3,4,2