79 Granada 4.1 EGR valve clicking after shutting engine off

I've been playing around with my vacuum line configuration. Until today my vacuum advance was connected directly to the manifold vacuum port. It had about 19 or 20 lbs of vacuum at idle and low rpm and the throttle had good response.

Okay today I connected the vacuum advance to the upper two port thermal vacuum switch with vacuum sourced from a ported vacuum port on the carb. No vacuum at idle and no more than maybe 5 lbs under throttle.

I'm pretty sure my thermal vacuum switches operation is questionable. Only God knows how long it's been since it was connected to anything, but that's beside the point of my post.

I understand that limiting the vacuum advance will cause the engine to run hotter and thus warm up faster. Anyhow after my test drive about 5 miles or so I shut it off and noticed a clicking noise almost like the sound of an aluminum engine cooling down. After further inspection and getting out my stethoscope I determined the sound is coming from the EGR valve. I'm not kidding it sounds like a clock ticking, lol. The EGR valve has been disconnected since I bought it.

I am curious if anyone else has any idea about the cause of this noise.

The lack of additional timing has obviously raised the exhaust temp, but I have no Thermactor Pump or a catalytic converter to take advantage of it.

Thanks,
Collins

Inside an EGR valve is always a load of CARBON!

https://www.youtube.com/watch?v=Dw89DHxa5c8

But a spring as well....




Increased heat, and you'll here it click.


See https://www.youtube.com/watch?v=_qB4hPymm6I at 5.26 mins. Lots of show and tell here!

Modern EGR's in the OBDII era are sprung electro magnets, and are quiet and if cleaned, work well.

Thanks, that video was interesting. He was like a kid opening a Christmas present, lol. I believe I will take my EGR valve off and check for carbon build up.

I already know that it won't hold a vacuum, but I have read that if it is a positive back pressure EGR it won't, unless the engine is being revved.

Do you know what years used a positive back pressure EGR? I work at Advance Auto and the parts listed for replacement don't specify.

I advanced the timing and not noticing the noise anymore. I was just wondering if repetitive clicking was an indication of something​ specific aside from the extra heat, like maybe a broken spring, bad diaphragm, or just carbon coated valve components. I'll post thoughts and photos.