I have owned my civic going on three years now, since i got it it has a had a ticking in the engine. I had the valves set and many people look at it. I was told that it was a leaking exhuast valve and the headers made the ticking more noticable. I recently bought a replacement motor that i was going to steal the head off of. When i tore down the donor engine the head seems very stiff to turn. How easily should you be able to turn a D16Z6 head? Thanks.