I am putting a new timing chain set in my 88' 4.2. When I tried to put the cover back on the cam was sticking out too far. With a few easy hits the cam slid back in so it was no longer hitting the cover. I replaced the cap on the back side of the cam (looks like a freeze plug). I could see that the cam had been rubbing against it. Is there something that is supposed to keep the cam in position? The manual say it is supposed to have a front bumper or grille. What is this. I am hoping you guys will set me straight on this. Thanks for the help.