My daughter's high mileage 91 Lumina with a 2.5L 4 cylinder broke a timing chain. After taking it apart I noticed when the valves close as I turn the cam with a wrench I can really feel each lobe. I've never noticed a V8 cam having quite the same feel. Is this the nature of a 4 cyl., having more degrees of separation between lobes, or do I have another undiagnosed problem?