[SWAMPRABBIT]

Get a long screw driver or a wooden rod. Start the motor and listen. One end touching motor. The other end put your ear to it. You will hear the noise through the screwdriver or wooden rod. Start at the valve cover and work you way down the side of the motor. The loudest point will be the location area of your knock.

 

[SWAMPRABBIT]

An exhaust leak at the head can sound like a knock sometimes. If you have pulled the exhaust a couple of times. You need to change the copper exhaust rings.

 

[SWAMPRABBIT]

When you put the 100 lbs of air to it it should have pushed the piston to the bottom. Remove the exhaust pipe and listen. Make sure both rockers are loose. Then if you hear any air coming out. You have a bad valve.

 

[SWAMPRABBIT]

While the valve cover is off. Rock the crank back and forth. Watch the cam. See how much you can rock it back and forth before the cam moves. That will give you an idea on timing chain stretch.