What could cause high blow by pressure worn turbo broken valve spring burnt valveleaky head gasket?

Excessive blowby means the oil pan is getting pressured up. A burnt valve or broken spring could cause compression to to leak back into the valve train area of the head. Worn piston rings will also do it. A worn turbo' if it's leaking oil past it's bearings and blowing oil into the intake manifold may make it look like excessive blow by when it's actually engine oil in the wrong place. My bet would be valves or rings.