Piston Damage? 1994 Car Repair

Hello,

I've been trying to fix the problem with my 1.0L engine for ages. It's knocking and smoking blue.
zkd, ventilschaftabdichtung usw. gemacht. drückt das öl durch beide krümmer am 4. Zylinder.
kw-screw, turbo, oil pressure - all good.

Piston rings defective??

Thank you.


Best regards, Manuel.

Valve stem seals need a certain break-in period.

1) What is the warm-up behavior like?
2) Check the compression of the engine when it is at operating temperature.
3) Post the result!