Before you pull the head, do a leakdown test to determine what cylinder has the problem.

This is where you place a piston at TDC / both valves closed then you pump air into cylinder. With a gas motor it is through the spark plug hole, a diesel it is through the injector or glow plug.

Also, don't randomly throw parts at the car, find the actual problem. ( RE installing a starter to cure exhaust smoke. )

Many people don't know much about a car so don't mistake lack of skills for malice.