I started my 68 Mustang up the other day and there was a clicking sound coming from the passenger side of the motor. I took the valve cover off and one of the rocker arms had slipped off. It looks like the bolt had backed off and it was very loose. The car has been sitting for 12 years (garage kept) but I was wondering if anyone would know why or how the rocker arm would do that?

 

There are a variety of reasons including loose bolts, worn out locks, rocker studs that have pulled out slightly, etc.

I recommend you readjust all of the valves and then check them again after 50 miles and periodically after that until you are confident they are staying tight.

 

My bet is on a collapsed lifter. fakesnakes advice is good, follow that.

 

Ok here is my update. We went in and tightened everything up and the engine started right up. After a few minutes of running the clicking sound came back from the same place. We took the rod out and it looked fine. I am waiting for the oil to drain to take the valve cover back off. I would be willing to bet that the rocker arm is loose again. does anyone know what else it could be?

 

Is it press in studs? They have been known to pull out. Otherwise, it could be a lifter as well.

 

Sorry for the delay, after thinking about this problem for a couple of days and remembering that this didn't start till we put a new carb on the engine and the carb was running very rich that it could be a carbon buildup problem. I decided to Seafoam my engine and all sounds have stopped. It looks like Seafoam saved the day.

 

haeh ?