Hello. My '67 is making a rhythmic noise at idle. It's loud, and sounds like metal clanging against metal. It seems to be coming from deep within the head or motor, toward the tranny.

She's an automatic with the 200 motor.

Here's a video with the noise:

I had the head rebuilt. I checked the exhaust system. I replaced the timing chain. There doesn't seem to be play in the crankshaft.

A little help please?

 

If it was a rocker or bearing, the sound would be consistent, rhymatic, same volume. Take a glance at your fan blade to make sure it's not hitting anything like the radiator or fan shroud. Don't stick you fingers in while it running. Turn the car off and manually rotate the fan by hand. Second, check the motor, insure all you spark plugs are screwed all the way down. Last, you can remove the valve cover and start the car briefly, this will allow you to look at the rockers to insure ALL are moving up and down.
Good rule of thumb, if the sound occurs for every single revolution of the crank its a bottom end problem, if it occurs every other turn of the crank its a top end valve train problem.

 

I agree with Groho, sounds like a fan blade, I'd take off all of the belts, should narrow it down.
You can put a long screwdriver handle in your ear and put the other end on the engine to see if's internal. If it's internal you'll know right away, the sound will be much louder and clearer.
Moving the screw drive to different parts of the engine might tell you where it's coming from.
For external noises I use a paper towel tube, put one end in your ear and point the other end to different parts of your engine compartment.

 

Check the flywheel.
(sometimes called the flex plate by ****-retentive types)

It could be cracked, loose torque converter nut, trans spacer plate, dust cover, etc.

Doesn't sound like a valve train noise, or anything internal, to me.
Check all the external rotating stuff. ...like the fan, as mentioned above.





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The noise seems to be coming from the rear of the head. Compression in the #6 cylinder is 45 lbs. Squirting oil in the cylinder only raises the compression by 5 lbs. Pulling the spark plug wire for that cylinder at idle barely changes the idle if at all.

Since the head was just rebuilt by a machine shop, I'm bringing it back there.

 

Was it making that noise before the head work?