I have a 318 with about 1500 miles on it. It recently started making a clicking noise that gets fairly loud when accelerating. I was unable to determine the source of the clicking until I unplugged the spark plug wire on cylinder #5. When the wire is removed the clicking stops. The Spark plug wire was replaced but made no difference. Any ideas of what it could be? I have my hunch but don't want to go there right now.

 

I would do a compression test before making too many guesses. A cylinder pressure test listening at the carb, exhaust pipe and crank breather can tell condition of intake, exhaust valves and rings.

 

All good advice there! If you have access to an IR laser thermometer, you might also want to check, and compare the exhaust manifold temperature of all the cylinders. What was the condition of the plug, compared to the others?

 

If your compression test is poor on that cylinder, do a wet compression test where you squirt a tablespoon of oil into that cylinder thru the spark plug hole. If the compression goes up then the oil helped seal the rings and you found the issue.

 

Could it be an exhaust manifold leak?

 

Unless you screwed up the rebuild which I doubt I would check exhaust gaskets

 

J -

Before you start going nuts, the two most likely culprits are an exhaust leak or a failed lifter, with the former be most likely. Since you know what cylinder it is, look around the exhaust port, top and bottom for any burn marks.

Archer