Did you do a valve job and valve seats on that engine and does it have the valve stem seals that rotate the valves.
In the video it seems like the noise is actually the exhaust valves closing since the exhaust is off you can hear it very easily. if you put an old head with new valves and didn't do the valve seat grind and lapping, I believe you'll end up with a noise quite like this.
You said you were chasing a vacuum leak, this makes me wonder if something was left inside of the intake. At idle engine vacuum is highest and thus if inside of the intake a bolt or something was in there it would move the most at idle.
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Last but not least. Using a mechanic's stethoscope, listen close to the thermostat, it may be noise from it opening and closing. If that is true you will not hear the noise when it is cold.
Hi Daniel,
Did you do a valve job and valve seats on that engine and does it have the valve stem seals that rotate the valves.
In the video it seems like the noise is actually the exhaust valves closing since the exhaust is off you can hear it very easily. if you put an old head with new valves and didn't do the valve seat grind and lapping, I believe you'll end up with a noise quite like this.
You said you were chasing a vacuum leak, this makes me wonder if something was left inside of the intake. At idle engine vacuum is highest and thus if inside of the intake a bolt or something was in there it would move the most at idle.