The owner who is now the only one touching my car is a MB tech. The lifters are new, are the ball studs part of the lifter? I am stuck because I have spent so much money on this car and the owner really want to make me happy. I'm torn between giving him one more chance to fix it and letting it sit in my drive way until I have the money to take it somewhere else. What all can make this noise that is easy to check? Is there a test to see if the valve guides are bad? I get a little smoke when I first start the car and this did not happen until I replaced the cams and lifters.