hi guys I need bit of advice i had problems with my head a year ago it started tapping, when we took rocker cover off one of the lifters were stuck when we managed get it out it scored the hole, I got a new recon head and new kent cam plus new oil pump, we had trouble getting oil pressure up on first startup , then once running it did about 50 miles tidy driving and same again one of the lifters got stuck scoring the head and fucked the new cam, what would be causing this? I have since had the bottom end rebuilt it wasnt knackerd but wernt preety, the head getting fitted this weekend so im just bit worried it going to happen again, any ideas guys?